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Cinema 4D TrainingIntroducing VRay

A short guide to the settings of VRayForC4D

Stuart Lynch

The C4D Vault presents

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ZIP ARCHIVE PASSWORDSherbetLemon

case sensitive

Project files can be found at http://www.thec4dvault.com/down/vrayguide.zip

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ZIP ARCHIVE PASSWORDSherbetLemon

case sensitive

Project files can be found at http://www.thec4dvault.com/down/vrayguide.zip

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TheC4DVault(.com)

TheC4DVault.com was created by Stuart Lynch and provides Cinema 4D training, resources and sample files for the C4D community. Stuart is a veteran Cinema 4D user with over 10 years of professional expe-rience in the industry and several years providing instructional information to intermediate users. This first in a series of new short instructional pdf ’s is aimed at providing the user with enough informa-tion to digest without becoming overwhelmed. It highlights the backend of VRay and relates the impor-tance of understanding the settings that make VRayForC4D one of the best render engines around. Over the coming months, TheC4DVault pdf booklets will cover a wide variety of topics, providing a free and reliable way to learn Cinema 4D. “I hope you enjoy this first addition and learn a thing or two about VRay in the process. Thanks for reading.”

Stuart Lynch http://www.project1media.com

Please make a minimal donation to keep the resource alive. *See Donate section at www.thec4dvault.com

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TheC4DVault(.com)

TheC4DVault.com was created by Stuart Lynch and provides Cinema 4D training, resources and sample files for the C4D community. Stuart is a veteran Cinema 4D user with over 10 years of professional expe-rience in the industry and several years providing instructional information to intermediate users. This first in a series of new short instructional pdf ’s is aimed at providing the user with enough informa-tion to digest without becoming overwhelmed. It highlights the backend of VRay and relates the impor-tance of understanding the settings that make VRayForC4D one of the best render engines around. Over the coming months, TheC4DVault pdf booklets will cover a wide variety of topics, providing a free and reliable way to learn Cinema 4D. “I hope you enjoy this first addition and learn a thing or two about VRay in the process. Thanks for reading.”

Stuart Lynch http://www.project1media.com

Please make a minimal donation to keep the resource alive. *See Donate section at www.thec4dvault.com

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It’s time to turn our C4D shot into a VRay scene. First activate VRay in the Render Settings - figure 1.4

figure 1.4

You’ll notice now a new VRay Bridge Option figure 1.5 has appeared for VRay on the left hand side

figure 1.5

Clicking the VRayBridge option will reveal the many VRay bridge parameters geared towards the final rendering setup.

Next click on the tab that says IndirectIllumination figure 1.6 and check the first box that says GI ON figure 1.7

figure 1.6

You’ve now successfully activated VRay and and activated GI.

Feel free to test the render.

figure 1.7

figure 1.8

Now that you’ve witnessed the true power of VRay, you might want to take it to the next level. Right click the light object in the Object Manager and scroll down to the VRay tags. From the list, you’ll want to add a VRayLight tag. figure 1.8.

figure 1.9

The information required to manipulate VRay lights specifically is now contained in the VRay light tag for future reference. figure 1.9 You can double click this tag at any time to retrieve this set of parameters.

If you were to search images.google with the term ‘VRay’, one of the first thing you’ll notice is the abundant usage of the Physical Sun/Sky setup. It’s a practical solution for lighting interiors and will serve as our first demonstration of the VRay engine at work.

In figure 1.1 we have the Sun light parameters which allow us to make changes to the Sun’s intensity and it’s physical properties. For this example we’re simply going to acti-vate the Sun/Sky and become familiar with the lighting it provides for the scene.

figure 1.1

In figure 1.2 I’ve created a primitive cube with 2 segments on each side. The geometry has been edited and 2 simple openings have been extruded on the most distant polygons.

The editor camera has been positioned in the center of the screen and I’ve exaggerated the field of view slightly to include both open-ings.

figure 1.2

figure 1.3

To complete this portion of the setup, I’ve added a simple target light figure 1.3.

Chapter 1: Introducing VRay - The Sun and Sky

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It’s time to turn our C4D shot into a VRay scene. First activate VRay in the Render Settings - figure 1.4

figure 1.4

You’ll notice now a new VRay Bridge Option figure 1.5 has appeared for VRay on the left hand side

figure 1.5

Clicking the VRayBridge option will reveal the many VRay bridge parameters geared towards the final rendering setup.

Next click on the tab that says IndirectIllumination figure 1.6 and check the first box that says GI ON figure 1.7

figure 1.6

You’ve now successfully activated VRay and and activated GI.

Feel free to test the render.

figure 1.7

figure 1.8

Now that you’ve witnessed the true power of VRay, you might want to take it to the next level. Right click the light object in the Object Manager and scroll down to the VRay tags. From the list, you’ll want to add a VRayLight tag. figure 1.8.

figure 1.9

The information required to manipulate VRay lights specifically is now contained in the VRay light tag for future reference. figure 1.9 You can double click this tag at any time to retrieve this set of parameters.

If you were to search images.google with the term ‘VRay’, one of the first thing you’ll notice is the abundant usage of the Physical Sun/Sky setup. It’s a practical solution for lighting interiors and will serve as our first demonstration of the VRay engine at work.

In figure 1.1 we have the Sun light parameters which allow us to make changes to the Sun’s intensity and it’s physical properties. For this example we’re simply going to acti-vate the Sun/Sky and become familiar with the lighting it provides for the scene.

figure 1.1

In figure 1.2 I’ve created a primitive cube with 2 segments on each side. The geometry has been edited and 2 simple openings have been extruded on the most distant polygons.

The editor camera has been positioned in the center of the screen and I’ve exaggerated the field of view slightly to include both open-ings.

figure 1.2

figure 1.3

To complete this portion of the setup, I’ve added a simple target light figure 1.3.

Chapter 1: Introducing VRay - The Sun and Sky

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Color mappingTo make a point stick with his students, my college instructor would occasionally use profanity. So let me say that using Color Mapping in your workflow will often save your ASS! There are plenty of headaches to come, trust me, but with this simple workflow you’ll avoid blown out light sources that can make or break a render.

It’s a straight forward concept to understand when illustrated with this amazing set of renders.

In figure 1.13 The area light in this simple room appears to give off the correct light intensity and illuminates the portion of the room closest to camera. But at the source, the light appears ‘nuked’ In figure 1.14 If we dial back the lighting intensity a little, the light at the source appears to have corrected itself, but at the expense of less light reaching the back of the room.

figure 1.15

figure 1.13 figure 1.14

In figure 1.15 the light intensity is restored to the brightness of figure 1.13, color mapping is applied and the light adequately reaches the entire space. Balance is accomplished.

The VRayLight tag contains a lot of impor-tant functionality and we’ll become familiar with all of the options as we progress.

For now, our intention is change the target spotlight to become a Sun light with a PhysicalSky

In the option Light type figure 1.4 Change from a Spot light to an Infinite light.

Also check Enable shadows

figure 1.10The light now is as it suggests, an infinite light and not yet a Sun Light. In order for the light to become a Sun Light we must click the Sun Light tag and make a few adjust-ments

figure 1.11

In figure 1.11 I have checked the boxes Physical Sun and Physical Sky. A test render figure 1.12 will now reveal a room illuminated by the physical qualities of the sun and sky together.

Focussing on the details of the render, it’s possible to notice that there’s a slight flaw in the accuracy of the lighting. The sunlight that enters the room looks overexposed, yet the subsequent light fall-off is too dramatic and occurs too quickly. Meaning, the rest of the room is too dark when compared to the intensity of the sun. Maybe it’s that the scene needs a fill light or perhaps we’ve missed the more GI ‘bounces’ option, after all it’s an interior scene.

Not so fast!

The solution in Color Mapping

figure 1.12

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Color mappingTo make a point stick with his students, my college instructor would occasionally use profanity. So let me say that using Color Mapping in your workflow will often save your ASS! There are plenty of headaches to come, trust me, but with this simple workflow you’ll avoid blown out light sources that can make or break a render.

It’s a straight forward concept to understand when illustrated with this amazing set of renders.

In figure 1.13 The area light in this simple room appears to give off the correct light intensity and illuminates the portion of the room closest to camera. But at the source, the light appears ‘nuked’ In figure 1.14 If we dial back the lighting intensity a little, the light at the source appears to have corrected itself, but at the expense of less light reaching the back of the room.

figure 1.15

figure 1.13 figure 1.14

In figure 1.15 the light intensity is restored to the brightness of figure 1.13, color mapping is applied and the light adequately reaches the entire space. Balance is accomplished.

The VRayLight tag contains a lot of impor-tant functionality and we’ll become familiar with all of the options as we progress.

For now, our intention is change the target spotlight to become a Sun light with a PhysicalSky

In the option Light type figure 1.4 Change from a Spot light to an Infinite light.

Also check Enable shadows

figure 1.10The light now is as it suggests, an infinite light and not yet a Sun Light. In order for the light to become a Sun Light we must click the Sun Light tag and make a few adjust-ments

figure 1.11

In figure 1.11 I have checked the boxes Physical Sun and Physical Sky. A test render figure 1.12 will now reveal a room illuminated by the physical qualities of the sun and sky together.

Focussing on the details of the render, it’s possible to notice that there’s a slight flaw in the accuracy of the lighting. The sunlight that enters the room looks overexposed, yet the subsequent light fall-off is too dramatic and occurs too quickly. Meaning, the rest of the room is too dark when compared to the intensity of the sun. Maybe it’s that the scene needs a fill light or perhaps we’ve missed the more GI ‘bounces’ option, after all it’s an interior scene.

Not so fast!

The solution in Color Mapping

figure 1.12

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It wouldn’t be fair to offer you this solution without some idea of what’s happening behind the scenes. After all, you did buy the book from a desire to learn. So if we apply the ‘Indoor’ settings from the guidelines on the previous page, we can draw comparison to the original Sun/Sky render.

figure 1.17 is the original without color map-ping applied (Gamma 1.0)figure 1.18 in exponential mode with the guide-line values (3.6/1.8/2.0) (Gamma 2.0)

figure 1.17

figure 1.18

In figure 1.17 we have the issue where the sun-light is not illuminating the scene correctly. In figure 1.18 the samples illuminate the shot correctly and the light intensity is well bal-anced. The difference lies in the mode Exponen-tial, this prevents colors from becoming too burned out and bright. It’ll saturate the colors as they reach too high of an intensity.

The darkness multiplier value increase to 3.6 indicates that the original output of grey/blue will have be multiplied by 3.6, giving rise to the additional light and brightness in the scene.

The brightness multiplier is increased to 1.8Which indicates that although the exponen-tial value has reduced overall brightness, it can still be multiplied to compensate for the dip you see in figure 1.19. You can consider it a compromise.

In figure figure 1.19 the brightness multiplier is being left at its default value of 1.0 and the sunlight would be too low in its intensity.

figure 1.19

FOR INDOOR SHOTS. Type: Exponential (some prefer HSV exponential)

Dark Multiplier: 3.6Brightness Multiplier: 1.8Gamma: Between 1.8 - 2.2 LinearWorkFlow - Check to ON

FOR OUTDOOR SCENES. Type: ReinhardMultiplier: 1.5 Burn Value: 0.5 Gamma: Between 1.8 - 2.2 LinearWorkFlow - Check to ON

If you’re not already aware of the implications of using a LWF - See the following PDF http://www.pixsim.co.uk/downloads/The_Beginners_Explanation_of_Gamma_Correction_and_Linear_Workflow.pdf

By default VRay uses the ‘Color Mapping’ type (menu option Type) Linear Multiply with default Dark and Bright Multiplier values set to 1

You will notice several other Types in this drop down menu.

ExponentialHSV ExponentialIntesity Exponential Gamma CorrectionIntesity Gamma Reinhard The most practical color mapping Type for interior rendering is Exponential mode (or HSV Exponential) For exterior shots, it is recommended to use Reinhard

The following settings are a general guideline for what these numbers should look like.

You can use find this function in VRay settings under Color Mapping. figure 1.16

figure 1.16

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It wouldn’t be fair to offer you this solution without some idea of what’s happening behind the scenes. After all, you did buy the book from a desire to learn. So if we apply the ‘Indoor’ settings from the guidelines on the previous page, we can draw comparison to the original Sun/Sky render.

figure 1.17 is the original without color map-ping applied (Gamma 1.0)figure 1.18 in exponential mode with the guide-line values (3.6/1.8/2.0) (Gamma 2.0)

figure 1.17

figure 1.18

In figure 1.17 we have the issue where the sun-light is not illuminating the scene correctly. In figure 1.18 the samples illuminate the shot correctly and the light intensity is well bal-anced. The difference lies in the mode Exponen-tial, this prevents colors from becoming too burned out and bright. It’ll saturate the colors as they reach too high of an intensity.

The darkness multiplier value increase to 3.6 indicates that the original output of grey/blue will have be multiplied by 3.6, giving rise to the additional light and brightness in the scene.

The brightness multiplier is increased to 1.8Which indicates that although the exponen-tial value has reduced overall brightness, it can still be multiplied to compensate for the dip you see in figure 1.19. You can consider it a compromise.

In figure figure 1.19 the brightness multiplier is being left at its default value of 1.0 and the sunlight would be too low in its intensity.

figure 1.19

FOR INDOOR SHOTS. Type: Exponential (some prefer HSV exponential)

Dark Multiplier: 3.6Brightness Multiplier: 1.8Gamma: Between 1.8 - 2.2 LinearWorkFlow - Check to ON

FOR OUTDOOR SCENES. Type: ReinhardMultiplier: 1.5 Burn Value: 0.5 Gamma: Between 1.8 - 2.2 LinearWorkFlow - Check to ON

If you’re not already aware of the implications of using a LWF - See the following PDF http://www.pixsim.co.uk/downloads/The_Beginners_Explanation_of_Gamma_Correction_and_Linear_Workflow.pdf

By default VRay uses the ‘Color Mapping’ type (menu option Type) Linear Multiply with default Dark and Bright Multiplier values set to 1

You will notice several other Types in this drop down menu.

ExponentialHSV ExponentialIntesity Exponential Gamma CorrectionIntesity Gamma Reinhard The most practical color mapping Type for interior rendering is Exponential mode (or HSV Exponential) For exterior shots, it is recommended to use Reinhard

The following settings are a general guideline for what these numbers should look like.

You can use find this function in VRay settings under Color Mapping. figure 1.16

figure 1.16

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Switch to the point tool and from the attributes manager uncheck ‘Only select Vis-ible Elements’

figure 2.5

In the Top viewport select the polygons that make up the front window and rear wall. Drag to the left as in figure 2.6

Repeat the process for the Right window as shown in figure 2.7

figure 2.6

In VRay it’s important to use as accurate a measurements as possible. This basic cube is 500cm x 200cm x 800cmand represents our small bedroom. figure 2.1

Chapter 2: The test sceneIn this chapter we’ll begin with a quick scene and will introduce the Physical Camera.

figure 2.1

In figure 2.2 I’ve added 5 segments to the X side of the model. Edit the model (hotkey C) and move the editor camera inside of the model.

figure 2.2

With the camera inside the model, select all polygons and reverse normals so that they’re facing inwards. (hotkeys U~R)

figure 2.3

Selecting two faces as shown below figure 2.4 Use inner extrude (hotkey I) and extrude (hotkey D) to create two window openings.

Here you could split the glass geometry for later (hotkeys U~S) or simply delete the two polygons.

figure 2.4 figure 2.7

Returning to the editor view, raise the lowest portion of the windows up slightly. figure 2.8

figure 2.8

Select all the polygons on the floor plane and extrude down slightly to create room for a thin moulding feature figure 2.9 Select all ceiling polygons, perform a slight inner extrude and then a regular extrude upwards. figure 2.10

figure 2.9

figure 2.10

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Switch to the point tool and from the attributes manager uncheck ‘Only select Vis-ible Elements’

figure 2.5

In the Top viewport select the polygons that make up the front window and rear wall. Drag to the left as in figure 2.6

Repeat the process for the Right window as shown in figure 2.7

figure 2.6

In VRay it’s important to use as accurate a measurements as possible. This basic cube is 500cm x 200cm x 800cmand represents our small bedroom. figure 2.1

Chapter 2: The test sceneIn this chapter we’ll begin with a quick scene and will introduce the Physical Camera.

figure 2.1

In figure 2.2 I’ve added 5 segments to the X side of the model. Edit the model (hotkey C) and move the editor camera inside of the model.

figure 2.2

With the camera inside the model, select all polygons and reverse normals so that they’re facing inwards. (hotkeys U~R)

figure 2.3

Selecting two faces as shown below figure 2.4 Use inner extrude (hotkey I) and extrude (hotkey D) to create two window openings.

Here you could split the glass geometry for later (hotkeys U~S) or simply delete the two polygons.

figure 2.4 figure 2.7

Returning to the editor view, raise the lowest portion of the windows up slightly. figure 2.8

figure 2.8

Select all the polygons on the floor plane and extrude down slightly to create room for a thin moulding feature figure 2.9 Select all ceiling polygons, perform a slight inner extrude and then a regular extrude upwards. figure 2.10

figure 2.9

figure 2.10

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figure 2.12

In figure 2.12, extrude the ceiling polygons to match the moulding extrusion.

Perform a simple select loop command with the polygon tool (hotkey U~L) figure 2.13 and Extrude slightly at 91°

Don’t be concerned if your shot is nothing like mine. If your scene has two openings I’ll forgive you.

Moving on.

figure 2.14 - ‘Test render for illustration purposes only’

Find a place where you’re happy with the viewport representation of your scene and add a regular Camera.

figure 2.14

‘Roughing out’ the lights

Add a Target Light and position yourself in the top view, try to find a placement for the target light where you would like the Sun to exist. figure 2.15

figure 2.15

Select VRay as your primary render engine in RenderSettings and as in the earlier ex-ample, check GI on in the IndirectIllumina-tion tab.

Add a VRay Light tag to your Target light, check enable shadows, change from spot light to infinite light. In the SunLight tab activate the Physical sun and Physical Sky.

Returning again to the editor view and ensuring you have you camera selected. Run your first render. figure 2.16

figure 2.16

Clearly not enough light entering the room on this angle. This issue of balance is more prominent than in my initial examples.

It’s time to apply Color Mapping to bring the room to life. figure 2.16

figure 2.17

REMINDER FOR INDOOR SHOTS. Type: Exponential (some prefer HSV exponential)Dark Multiplier: 3.6Brightness Multiplier: 1.8Gamma: Between 1.8 - 2.2 LinearWorkFlow - Check to ON

A small improvement.

Select the wall polygons in between the win-dows and extrude. figure 2.11

figure 2.11

figure 2.13

Page 16 Page 17

figure 2.12

In figure 2.12, extrude the ceiling polygons to match the moulding extrusion.

Perform a simple select loop command with the polygon tool (hotkey U~L) figure 2.13 and Extrude slightly at 91°

Don’t be concerned if your shot is nothing like mine. If your scene has two openings I’ll forgive you.

Moving on.

figure 2.14 - ‘Test render for illustration purposes only’

Find a place where you’re happy with the viewport representation of your scene and add a regular Camera.

figure 2.14

‘Roughing out’ the lights

Add a Target Light and position yourself in the top view, try to find a placement for the target light where you would like the Sun to exist. figure 2.15

figure 2.15

Select VRay as your primary render engine in RenderSettings and as in the earlier ex-ample, check GI on in the IndirectIllumina-tion tab.

Add a VRay Light tag to your Target light, check enable shadows, change from spot light to infinite light. In the SunLight tab activate the Physical sun and Physical Sky.

Returning again to the editor view and ensuring you have you camera selected. Run your first render. figure 2.16

figure 2.16

Clearly not enough light entering the room on this angle. This issue of balance is more prominent than in my initial examples.

It’s time to apply Color Mapping to bring the room to life. figure 2.16

figure 2.17

REMINDER FOR INDOOR SHOTS. Type: Exponential (some prefer HSV exponential)Dark Multiplier: 3.6Brightness Multiplier: 1.8Gamma: Between 1.8 - 2.2 LinearWorkFlow - Check to ON

A small improvement.

Select the wall polygons in between the win-dows and extrude. figure 2.11

figure 2.11

figure 2.13

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Bringing the shot to life.

From the Material Manager add a new VRay Advanced Material to the scene. figure 2.18

So far we haven’t included any materials in our scene. VRay responds to color change quite dramatically, as does color in the real world. If we add a tiled wood texture to the floor, the bounced light from the wood and its color values will have an affect on the scene. Let’s explore further......

figure 2.18Assign the new VRay Ad-vanced Material to your cube object in the OM (object manager). figure 2.19

I’ve named my material ‘base’figure 2.19

Double click the Material ‘Wood’ In the Diffuse Layer - Texture map slot. Load a wood tile texture figure 2.21

Create a second VRay Advanced Material and change the name to ‘wood’

Select all floor polygons and drag the ‘wood’ material over the polygon selection figure 2.20

figure 2.20

figure 2.21

In the OM select (click) the wood material tag. In the Attributes Manager, change the projection mode from Spherical to Cubic Using the texture axis tool and the scale tool figure 2.22 Scale the wood texture to fit your scene.

figure 2.22

Running a new test render, notice how the wooden floor is affecting the lighting in the rest of the scene. figure 2.23

figure 2.23

Make a few adjustments to your camera po-sition and to the SunLight and try to balance both lighting direction and composition.

figure 2.24

figure 2.24

In this next phase of scene creation, we’ll start blocking out some objects with simple geometry to get a better feel for composition.

Place Cube primitive objects and position them where the bed, side tables and cabinet would potentially be.

The presence of more white objects has changed the dynamic lighting of the scene once again. figure 2.25

figure 2.25

Adding some additional materials with variations in color (preferably chosen to represent how you imagine your scene) we’re able to improve upon the overall feel of the shot. figure 2.26

figure 2.26

With all of these geometry additions you may have noticed that the light in the room has taken a significant dip in brightness. On the next page we’ll discuss the Physical Camera and how to implement photographic values in order to restore the balance.

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Bringing the shot to life.

From the Material Manager add a new VRay Advanced Material to the scene. figure 2.18

So far we haven’t included any materials in our scene. VRay responds to color change quite dramatically, as does color in the real world. If we add a tiled wood texture to the floor, the bounced light from the wood and its color values will have an affect on the scene. Let’s explore further......

figure 2.18Assign the new VRay Ad-vanced Material to your cube object in the OM (object manager). figure 2.19

I’ve named my material ‘base’figure 2.19

Double click the Material ‘Wood’ In the Diffuse Layer - Texture map slot. Load a wood tile texture figure 2.21

Create a second VRay Advanced Material and change the name to ‘wood’

Select all floor polygons and drag the ‘wood’ material over the polygon selection figure 2.20

figure 2.20

figure 2.21

In the OM select (click) the wood material tag. In the Attributes Manager, change the projection mode from Spherical to Cubic Using the texture axis tool and the scale tool figure 2.22 Scale the wood texture to fit your scene.

figure 2.22

Running a new test render, notice how the wooden floor is affecting the lighting in the rest of the scene. figure 2.23

figure 2.23

Make a few adjustments to your camera po-sition and to the SunLight and try to balance both lighting direction and composition.

figure 2.24

figure 2.24

In this next phase of scene creation, we’ll start blocking out some objects with simple geometry to get a better feel for composition.

Place Cube primitive objects and position them where the bed, side tables and cabinet would potentially be.

The presence of more white objects has changed the dynamic lighting of the scene once again. figure 2.25

figure 2.25

Adding some additional materials with variations in color (preferably chosen to represent how you imagine your scene) we’re able to improve upon the overall feel of the shot. figure 2.26

figure 2.26

With all of these geometry additions you may have noticed that the light in the room has taken a significant dip in brightness. On the next page we’ll discuss the Physical Camera and how to implement photographic values in order to restore the balance.

Page 20 Page 21

Introduction to the Physical cameraThe Physical Camera in VRay allows us to reproduce the parameters of a real world camera. To improve our scene without further adjusting the Color Mapping or the default lighting intensity of the Sun, we’ll implement the Physical Camera and make use of its features such as ISO and FStop.

From the OM select your scene Camera, right click and apply a VRay Physical Cam-era tag from the VRay Bridge Tags submenu. figure 2.27

figure 2.27

If you test a new render you would notice that no significant changes have occurred.

Though the default settings of the VRay Physical camera provide a similar result, they differ greatly from a camera that has no Physical properties.

The proof is in the numbers. In the VRay Light tag under the Sun light parameters you’ll see two separate values. Intensity multiplier for Phys Cam : 1Intensity multiplier for Std Cam: 0.037

The sun intensity is divided by exactly 270 to work at the default value of the standard camera.

It’s good practice to use the Physical camera for all of your scenes.

We’ll look more closely at comparisons in a later chapter, for now we’re occupied with increasing the exposure values of our scene without making any adjustments to light intensity. Click the VRay Physical Camera tagUnder the Tab - Lens parameters.

Scroll down to Film ISO and change the value from 100 to 400

A test render produces this result figure 2.28

figure 2.28

figure 2.26 ‘Old result for comparison’

An increase in Film ISO values from 400 to 1600 figure 2.29 increases the film sensitivity further and subsequently alters the bright-ness of the scene. Changes in F-Stop values can also be made to compensate for brightness. Shutter speed can typically be left alone, although it is an important value when intro-ducing motionblur into your workflow.

figure 2.29

If you’d like to continue with your scene and start placing actual geometry or re-working the blocked out models to become realistic fixtures in the room. Feel free.

figure 2.30

In figure 2.30 I’ve added a new bed and a some subtle blurry reflections (refereed to as Glossiness reflections in VRay) to the wood material. Although I’ll shortly be introducing more detailed information on the VRay Advanced Material, if you want to add this effect to your current scene, I’ll show you the quick way. Activate a Specular layer in your wood mate-rial and input a Glossiness reflection value of 0.8.

figure 2.31

figure 2.32

A couple of tweaks later and some stock models from my collection. figure 2.31

Few renders looks complete without a little post work. figure 2.32

Page 20 Page 21

Introduction to the Physical cameraThe Physical Camera in VRay allows us to reproduce the parameters of a real world camera. To improve our scene without further adjusting the Color Mapping or the default lighting intensity of the Sun, we’ll implement the Physical Camera and make use of its features such as ISO and FStop.

From the OM select your scene Camera, right click and apply a VRay Physical Cam-era tag from the VRay Bridge Tags submenu. figure 2.27

figure 2.27

If you test a new render you would notice that no significant changes have occurred.

Though the default settings of the VRay Physical camera provide a similar result, they differ greatly from a camera that has no Physical properties.

The proof is in the numbers. In the VRay Light tag under the Sun light parameters you’ll see two separate values. Intensity multiplier for Phys Cam : 1Intensity multiplier for Std Cam: 0.037

The sun intensity is divided by exactly 270 to work at the default value of the standard camera.

It’s good practice to use the Physical camera for all of your scenes.

We’ll look more closely at comparisons in a later chapter, for now we’re occupied with increasing the exposure values of our scene without making any adjustments to light intensity. Click the VRay Physical Camera tagUnder the Tab - Lens parameters.

Scroll down to Film ISO and change the value from 100 to 400

A test render produces this result figure 2.28

figure 2.28

figure 2.26 ‘Old result for comparison’

An increase in Film ISO values from 400 to 1600 figure 2.29 increases the film sensitivity further and subsequently alters the bright-ness of the scene. Changes in F-Stop values can also be made to compensate for brightness. Shutter speed can typically be left alone, although it is an important value when intro-ducing motionblur into your workflow.

figure 2.29

If you’d like to continue with your scene and start placing actual geometry or re-working the blocked out models to become realistic fixtures in the room. Feel free.

figure 2.30

In figure 2.30 I’ve added a new bed and a some subtle blurry reflections (refereed to as Glossiness reflections in VRay) to the wood material. Although I’ll shortly be introducing more detailed information on the VRay Advanced Material, if you want to add this effect to your current scene, I’ll show you the quick way. Activate a Specular layer in your wood mate-rial and input a Glossiness reflection value of 0.8.

figure 2.31

figure 2.32

A couple of tweaks later and some stock models from my collection. figure 2.31

Few renders looks complete without a little post work. figure 2.32

Page 22 Page 23

Chapter 3: Introducing VrayBridge render settingsQuality is very important when we think about final renders, but this shouldn’t always come at the cost of lengthy render times. Through exploring VRay’s render settings we’ll learn to tweak the parameters in order to get the best results in an optimal amount of time.

In this section we’ll optimize the VRay Render Settings and then explore the method behind the mad-ness. Open the example bedroom.c4d open from www.thec4dvault.com and lets begin.

figure 3.1

From the Tab Indirect Illumination (GI) select ‘01_IR-LC_very very fast’ from the GI Preset list

IR refers to Irradiance MapLC refers to Light Cache

In the Primary and Secondary bouncesyou can see the two modes being selected. With this setup the Light Cache will be cal-culated first. figure 3.3

figure 3.2

After successful completion of Light Cach-ing, the Engine then begins computation the Irradiance Map.

A simplified explanation of the Irradiance map is to imagine a point cloud that origi-nates from the Camera and projects out-wards into the scene. In figure 3.6 I’m using a VRay resource called IMapViewer.exe. With this we’re able to view the resulting IR map in its raw form. From the camera perspective in the bottom left corner, it’s quite easy to visualize the job of the Irradiance map. There are no samples outside of the Camera view and so we can conclude, it only samples what it needs to see.

figure 3.4 ‘The familiar Light Cache calculation’

figure 3.6

figure 3.5

At these low settings rendering with Light Cache as both a first and second bounces as with figure 3.5 would produce some odd splotchy results. Although with the correct values, this tech-nique is equal to Unbiased rendering. GI Preset 19_LC_LC_PPT_unbiased is set up to render in this way.

The Light Cache is an approximation of the global illumination in the scene. figure 3.4

figure 3.3 figure 3.7

The simple scene below is the resulting figure 3.7 render from the above calculation.

The more refined the Irradiance map settings are, the better it is able to assist in rendering smaller details. This also comes at the cost of render time.

Objects such as walls and floors require very little IR sampling, but a detailed ornament on a table needs more refined samples to reach the tight spaces.

Providing adequate coverage is much less of a struggle than it may seem. VRay comes loaded with presets that provide an excellent starting point in most cases.

figure 3.8

The DMC Sampler figure 3.8 is the VRay control Room. These 4 values basically de-termine how VRay uses its adaptive sampler, which I’ll explain later.

The engine itself uses deterministic Monte Carlo sampling (DMC), which is a high quality approximation GI algorithm. The better the settings, the more reliable and ac-curate that approximation becomes. It’s not imperative that we learn exactly how the backend of VRay works. What’s impor-tant is that we understand how these vast amounts of values will affect our end results.

We’ll need to break them down a little in order to make sense of them.

Page 22 Page 23

Chapter 3: Introducing VrayBridge render settingsQuality is very important when we think about final renders, but this shouldn’t always come at the cost of lengthy render times. Through exploring VRay’s render settings we’ll learn to tweak the parameters in order to get the best results in an optimal amount of time.

In this section we’ll optimize the VRay Render Settings and then explore the method behind the mad-ness. Open the example bedroom.c4d open from www.thec4dvault.com and lets begin.

figure 3.1

From the Tab Indirect Illumination (GI) select ‘01_IR-LC_very very fast’ from the GI Preset list

IR refers to Irradiance MapLC refers to Light Cache

In the Primary and Secondary bouncesyou can see the two modes being selected. With this setup the Light Cache will be cal-culated first. figure 3.3

figure 3.2

After successful completion of Light Cach-ing, the Engine then begins computation the Irradiance Map.

A simplified explanation of the Irradiance map is to imagine a point cloud that origi-nates from the Camera and projects out-wards into the scene. In figure 3.6 I’m using a VRay resource called IMapViewer.exe. With this we’re able to view the resulting IR map in its raw form. From the camera perspective in the bottom left corner, it’s quite easy to visualize the job of the Irradiance map. There are no samples outside of the Camera view and so we can conclude, it only samples what it needs to see.

figure 3.4 ‘The familiar Light Cache calculation’

figure 3.6

figure 3.5

At these low settings rendering with Light Cache as both a first and second bounces as with figure 3.5 would produce some odd splotchy results. Although with the correct values, this tech-nique is equal to Unbiased rendering. GI Preset 19_LC_LC_PPT_unbiased is set up to render in this way.

The Light Cache is an approximation of the global illumination in the scene. figure 3.4

figure 3.3 figure 3.7

The simple scene below is the resulting figure 3.7 render from the above calculation.

The more refined the Irradiance map settings are, the better it is able to assist in rendering smaller details. This also comes at the cost of render time.

Objects such as walls and floors require very little IR sampling, but a detailed ornament on a table needs more refined samples to reach the tight spaces.

Providing adequate coverage is much less of a struggle than it may seem. VRay comes loaded with presets that provide an excellent starting point in most cases.

figure 3.8

The DMC Sampler figure 3.8 is the VRay control Room. These 4 values basically de-termine how VRay uses its adaptive sampler, which I’ll explain later.

The engine itself uses deterministic Monte Carlo sampling (DMC), which is a high quality approximation GI algorithm. The better the settings, the more reliable and ac-curate that approximation becomes. It’s not imperative that we learn exactly how the backend of VRay works. What’s impor-tant is that we understand how these vast amounts of values will affect our end results.

We’ll need to break them down a little in order to make sense of them.

Page 24 Page 25

Back to the DMC sampler, add the values from figure 3.10

figure 3.10Adaptive amount will be left alone.Minimum samples have been reduced from 8 to 4 Noise threshold was in an okay place with 0.01, so we won’t touch that either.Global Subdivs multiplier is set 0.5, down from 1.

In the tab Indirect Illumination (GI) click the Irradiance Map arrow to reveal more set-tings figure 3.11change the Hemispheric SubD

Anti Aliasing (AA) is another important fac-tor in determining final VRay render quality.

The Adaptive DMC Anti Aliasing mode figure 3.9 and the DMC sampler figure 3.8 are tied in very closely, especially when compared to other Anti Aliasing techniques like the Adaptive Subdivision sampler

figure 3.9

figure 3.11

figure 3.12

figure 3.12For Hemispheric SubDivision enter the value: 30 For Interpolated samples enter a value of: 10

We can ignore the other settings for now.

figure 3.13

Still in the tab Indirect Illumination (GI) click the Light Cache arrow figure 3.11

In here we’ll simply be changing the Samples Ratio from 1/2 to 1/16 figure 3.13

Finally under the Options tab un-check the Glossy Effects to prevent any blurry reflec-tions from calculating figure 3.14

figure 3.14Now we can run our first preview quality render at ultra fast speed.

figure 3.15The result is awful, yet it took only 12 sec-onds to render at 1280x720.

This very low setting is a perfect place to start from if you’re blocking out the scene and need to make quick decisions.

We’ve barely scratched the surface of this new information and I have you dialing in numbers that probably make no sense to you whatsoever.

My instructional method is to teach through example. Once you’re familiarized with the process it will start to become second nature.

Yet that is only part of the equation.

It is also important to have a basic under-standing of why each value works the way it does.

In this next section we’ll adjust for a final render a along the way I’ll point out some of the method behind the madness.

figure 3.16If your render happens to look as it does in figure 3.16, it would be because you haven’t yet applied Color Mapping. Not mentioning it this was an intentional test.

Page 24 Page 25

Back to the DMC sampler, add the values from figure 3.10

figure 3.10Adaptive amount will be left alone.Minimum samples have been reduced from 8 to 4 Noise threshold was in an okay place with 0.01, so we won’t touch that either.Global Subdivs multiplier is set 0.5, down from 1.

In the tab Indirect Illumination (GI) click the Irradiance Map arrow to reveal more set-tings figure 3.11change the Hemispheric SubD

Anti Aliasing (AA) is another important fac-tor in determining final VRay render quality.

The Adaptive DMC Anti Aliasing mode figure 3.9 and the DMC sampler figure 3.8 are tied in very closely, especially when compared to other Anti Aliasing techniques like the Adaptive Subdivision sampler

figure 3.9

figure 3.11

figure 3.12

figure 3.12For Hemispheric SubDivision enter the value: 30 For Interpolated samples enter a value of: 10

We can ignore the other settings for now.

figure 3.13

Still in the tab Indirect Illumination (GI) click the Light Cache arrow figure 3.11

In here we’ll simply be changing the Samples Ratio from 1/2 to 1/16 figure 3.13

Finally under the Options tab un-check the Glossy Effects to prevent any blurry reflec-tions from calculating figure 3.14

figure 3.14Now we can run our first preview quality render at ultra fast speed.

figure 3.15The result is awful, yet it took only 12 sec-onds to render at 1280x720.

This very low setting is a perfect place to start from if you’re blocking out the scene and need to make quick decisions.

We’ve barely scratched the surface of this new information and I have you dialing in numbers that probably make no sense to you whatsoever.

My instructional method is to teach through example. Once you’re familiarized with the process it will start to become second nature.

Yet that is only part of the equation.

It is also important to have a basic under-standing of why each value works the way it does.

In this next section we’ll adjust for a final render a along the way I’ll point out some of the method behind the madness.

figure 3.16If your render happens to look as it does in figure 3.16, it would be because you haven’t yet applied Color Mapping. Not mentioning it this was an intentional test.

Page 26 Page 27

Creating a higher quality renderReload the example bedroom.c4d Attempt this without illustration (please)

#1 In the tab Indirect Illumination (GI) se-lect ‘03_IR-LC_medium’ from the GI Preset list and check the box GI On

#2 In the Irradiance Map sub menuMin Rate: -3Max rate: -1Hemispheric SubDivision: 55 Interpolated samples: 15 Leave every other IR setting alone #3 In the Light Cache submenu

Un-check Override LC SubdivisionSubdivision: 1000 Scroll down a little to Reconstruction parameters

Un-check Enable LC retrace

#3 In DMC Sampler tab

Adaptive amount: 0.85Noise threshold: 0.01Minimum samples 8Global Subdiv multiplier: 1 #4 In the Antialiasing tab

Antialiasing type: DMC samplerFilter on: Check Filter type: Catmull-RomMin SubD: 1 Max SubD: 5

#5 Color Mapping tab Type: Exponential (some prefer HSV exponential)

Dark Multiplier: 3.6Brightness Multiplier: 1.8Gamma: Between 1.8 - 2.2 LinearWorkFlow - Check to ON

#6 Time to render.

figure 3.17

My render time at 1280x720 on a 6 core I7-980x (running at 4.4ghz)was 1 min 48 seconds. For a scene with Global illumination that’s not a bad time. But was the result ready to send to a client? Well, aside from the fact that the scene is pretty bad to begin with, I’d still have to go with “no”. There’s artifacting issues in a couple of areas, too much noise in the wood and black glossy metal and it needs a little more. It feels close but it could use a little more to sell it as final.

Indirect Illumination - Irradiance mapTempting as it may appear to ignore this section and rely upon VRay’s preset values, I would recommend against it. Presets only solve half of the equation, they have no affect on AA or the DMC sampler and they’re not intended to provide a complete setup for your scene. Instead see the presets as a good starting point. The Medium quality preset is sufficient for most projects and only requires a few minor adjustments to bring it up to speed.

When rendering a GI shot in VRay, the engine requires two solutions to produce ac-curate GI results. Those are the Primary and Secondary bounces. In figure 3.18 I’ve turned off secondary bounces and left the Primary bounces as: Irradiance map. With only one GI engine actively calculating, a correct GI solution has not been possible.

This is visible as the dark areas in the image.

Each of the approximation methods has its own very specific parameters.

The IR map (IR map - Irradiance map) has many options for the management of correctly calculating samples, sample accuracy and de-tail enhancement. It also has a section used exclusively for animation,. The first two parameters you come across are Min rate and Max rate. These settings relate to the size of the IR map calculation.

The Min value “determines the resolution for the first GI pass”. The Max value determines the resolution for the last GI pass.

A Max value of 0 would imply that the resolution of the last GI pass is equal to the dimension of your scene resolution.

A value of -1 is equal to half the resolution of the dimensions of your scene resolution. A Min value of :-4 and a A Max value of: 0,

....would create 5 passes during the caching process. ( -4, -3. -2, -1 and 0)

The Max value 0 is typically not needed for less complex scenes.

figure 3.18

So far we’ve used only two of the five possible GI engines in these slots. The preset values highlight other combinations, though the IR and LC is our focus for the time be-ing. As Irradiance map is our primary bounce, we’ll introduce its settings first.

Page 26 Page 27

Creating a higher quality renderReload the example bedroom.c4d Attempt this without illustration (please)

#1 In the tab Indirect Illumination (GI) se-lect ‘03_IR-LC_medium’ from the GI Preset list and check the box GI On

#2 In the Irradiance Map sub menuMin Rate: -3Max rate: -1Hemispheric SubDivision: 55 Interpolated samples: 15 Leave every other IR setting alone #3 In the Light Cache submenu

Un-check Override LC SubdivisionSubdivision: 1000 Scroll down a little to Reconstruction parameters

Un-check Enable LC retrace

#3 In DMC Sampler tab

Adaptive amount: 0.85Noise threshold: 0.01Minimum samples 8Global Subdiv multiplier: 1 #4 In the Antialiasing tab

Antialiasing type: DMC samplerFilter on: Check Filter type: Catmull-RomMin SubD: 1 Max SubD: 5

#5 Color Mapping tab Type: Exponential (some prefer HSV exponential)

Dark Multiplier: 3.6Brightness Multiplier: 1.8Gamma: Between 1.8 - 2.2 LinearWorkFlow - Check to ON

#6 Time to render.

figure 3.17

My render time at 1280x720 on a 6 core I7-980x (running at 4.4ghz)was 1 min 48 seconds. For a scene with Global illumination that’s not a bad time. But was the result ready to send to a client? Well, aside from the fact that the scene is pretty bad to begin with, I’d still have to go with “no”. There’s artifacting issues in a couple of areas, too much noise in the wood and black glossy metal and it needs a little more. It feels close but it could use a little more to sell it as final.

Indirect Illumination - Irradiance mapTempting as it may appear to ignore this section and rely upon VRay’s preset values, I would recommend against it. Presets only solve half of the equation, they have no affect on AA or the DMC sampler and they’re not intended to provide a complete setup for your scene. Instead see the presets as a good starting point. The Medium quality preset is sufficient for most projects and only requires a few minor adjustments to bring it up to speed.

When rendering a GI shot in VRay, the engine requires two solutions to produce ac-curate GI results. Those are the Primary and Secondary bounces. In figure 3.18 I’ve turned off secondary bounces and left the Primary bounces as: Irradiance map. With only one GI engine actively calculating, a correct GI solution has not been possible.

This is visible as the dark areas in the image.

Each of the approximation methods has its own very specific parameters.

The IR map (IR map - Irradiance map) has many options for the management of correctly calculating samples, sample accuracy and de-tail enhancement. It also has a section used exclusively for animation,. The first two parameters you come across are Min rate and Max rate. These settings relate to the size of the IR map calculation.

The Min value “determines the resolution for the first GI pass”. The Max value determines the resolution for the last GI pass.

A Max value of 0 would imply that the resolution of the last GI pass is equal to the dimension of your scene resolution.

A value of -1 is equal to half the resolution of the dimensions of your scene resolution. A Min value of :-4 and a A Max value of: 0,

....would create 5 passes during the caching process. ( -4, -3. -2, -1 and 0)

The Max value 0 is typically not needed for less complex scenes.

figure 3.18

So far we’ve used only two of the five possible GI engines in these slots. The preset values highlight other combinations, though the IR and LC is our focus for the time be-ing. As Irradiance map is our primary bounce, we’ll introduce its settings first.

Page 28 Page 29

You could ask why not just have a Min value of -1 and a Max value of -1? Or a fixed value? The smaller values in the Min setting (-4 for example) are important for sampling the bigger details (walls etc). The larger values in Max (-1 or 0) are for sampling the finer details.

You would rarely encounter a need to use a positive value like 1 in the Max setting. If it occurs to you to do so, it would be wise to look elsewhere before concluding that this is the solution to your rendering woes.

Min and Max however, are only part of the solution. In figure 3.19 the low settings I’ve deliberately chosen are creating very obvious splotches. This suggests that are settings are way off the mark and need to be re-worked.

A Hemispheric SubDivision is part of the Ir-radiance map and is used to determine “the quality of individual GI samples”. Relating only to the samples of IR map in this case.

We can look here to improve upon our IR map caching process. A good starting place when attempting a final render is around the 50 mark. Values upwards of 150 are not unheard of for problematic renders, though typically you’ll find that 50-80 is adequate.

Interpolated samples refers to the interpola-tion of the IR map samples. This calculation look towards the range of existing data and attempts to refine that process further. With this setting - Too high a value is likely to blur the solution, Too low and the samples will receive no interpolation. So we can determine that some Interpolated samples are necessary.

To compliment the Hemispheric SubDivi-sion, a value of approximately 15-30 is usu-ally always sufficient.

figure 3.19

In all of the above examples Hemispheric SubDivision has a value of 50

In figure 3.21 the Interpolated samples value is 1, which at close inspection is too few samplesIn figure 3.22 the Interpolated samples value is 100. At this value the samples tend to become blurred. In figure 3.23 the Interpolated samples value is 20. This is practical amount for most renders.

At this scale it is perhaps difficult to see a huge difference. Also any remaining noise issues you’re seeing would then be an issue with the DMC sampler and not the IR Map.

figure 3.21 figure 3.22 figure 3.23

There are clearly other settings in the Irradiance map parameters, yet in the interest of not becoming bogged down with too much input, I’ll only briefly highlight their usage. To the left of the Min/Max rates lie the Intensity Threshold, Normal Threshold and Distance Threshold.

These settings refer to individual sensitivities to light intensity changes, surface normal changes and changes in the distance between surfaces. I would leave these values alone and let the provided preset values guide you until you become more familiar. There are occasions with objects such as ‘thin blinds’ where adjustments to these settings will benefit your render. In the Detail enhancement section are a couple of additional parameters. This function as the name implies creates additional detail (to small detailed objects, not really useful in a typical scene).Utilizing this process will force the GI algorithm to compute with Brute Force GI in places that are dif-ficult for the IR map to reach. When using this function it is often necessary to consider lower overall IR Map settings.With this option checked we’re dependant upon Detail enhancement to enhance our render, the remain-ing settings would therefore only need to made be suitable for coverage of the larger objects. Note: This is because large objects such walls/ceilings typically get adequate coverage from fewer samples. In my professional career I have used the Detail enhancement function no more than 3 times.

Refining the IR map settings is how we prevent splotches and other inaccuracies. It ensures that this approximation method (our primary light bounce) will provide enough samples to assist in a flawless final render. Note: Over estimating the values can cre-ate unnecessarily long render times. Under estimating causes artifacting. (Not to be confused with noise)

figure 3.20

Look to the next page for some comparisons.

Page 28 Page 29

You could ask why not just have a Min value of -1 and a Max value of -1? Or a fixed value? The smaller values in the Min setting (-4 for example) are important for sampling the bigger details (walls etc). The larger values in Max (-1 or 0) are for sampling the finer details.

You would rarely encounter a need to use a positive value like 1 in the Max setting. If it occurs to you to do so, it would be wise to look elsewhere before concluding that this is the solution to your rendering woes.

Min and Max however, are only part of the solution. In figure 3.19 the low settings I’ve deliberately chosen are creating very obvious splotches. This suggests that are settings are way off the mark and need to be re-worked.

A Hemispheric SubDivision is part of the Ir-radiance map and is used to determine “the quality of individual GI samples”. Relating only to the samples of IR map in this case.

We can look here to improve upon our IR map caching process. A good starting place when attempting a final render is around the 50 mark. Values upwards of 150 are not unheard of for problematic renders, though typically you’ll find that 50-80 is adequate.

Interpolated samples refers to the interpola-tion of the IR map samples. This calculation look towards the range of existing data and attempts to refine that process further. With this setting - Too high a value is likely to blur the solution, Too low and the samples will receive no interpolation. So we can determine that some Interpolated samples are necessary.

To compliment the Hemispheric SubDivi-sion, a value of approximately 15-30 is usu-ally always sufficient.

figure 3.19

In all of the above examples Hemispheric SubDivision has a value of 50

In figure 3.21 the Interpolated samples value is 1, which at close inspection is too few samplesIn figure 3.22 the Interpolated samples value is 100. At this value the samples tend to become blurred. In figure 3.23 the Interpolated samples value is 20. This is practical amount for most renders.

At this scale it is perhaps difficult to see a huge difference. Also any remaining noise issues you’re seeing would then be an issue with the DMC sampler and not the IR Map.

figure 3.21 figure 3.22 figure 3.23

There are clearly other settings in the Irradiance map parameters, yet in the interest of not becoming bogged down with too much input, I’ll only briefly highlight their usage. To the left of the Min/Max rates lie the Intensity Threshold, Normal Threshold and Distance Threshold.

These settings refer to individual sensitivities to light intensity changes, surface normal changes and changes in the distance between surfaces. I would leave these values alone and let the provided preset values guide you until you become more familiar. There are occasions with objects such as ‘thin blinds’ where adjustments to these settings will benefit your render. In the Detail enhancement section are a couple of additional parameters. This function as the name implies creates additional detail (to small detailed objects, not really useful in a typical scene).Utilizing this process will force the GI algorithm to compute with Brute Force GI in places that are dif-ficult for the IR map to reach. When using this function it is often necessary to consider lower overall IR Map settings.With this option checked we’re dependant upon Detail enhancement to enhance our render, the remain-ing settings would therefore only need to made be suitable for coverage of the larger objects. Note: This is because large objects such walls/ceilings typically get adequate coverage from fewer samples. In my professional career I have used the Detail enhancement function no more than 3 times.

Refining the IR map settings is how we prevent splotches and other inaccuracies. It ensures that this approximation method (our primary light bounce) will provide enough samples to assist in a flawless final render. Note: Over estimating the values can cre-ate unnecessarily long render times. Under estimating causes artifacting. (Not to be confused with noise)

figure 3.20

Look to the next page for some comparisons.

Page 30 Page 31

Indirect Illumination - The Light Cache.The light cache (once again) is the approximation of global illumination in the scene. Spot3D.com “The light cache is built by tracing many eye paths from the camera.”

figure 3.24

I have to admit the first time I saw this menu, I felt a lot less threatened by it than I did the Irradiance map options.

In our current IR - LC setup we’re depending on the Light Cache portion of this solution to computer the secondary bounces.

In figure 3.24 the Overide LC subdivision box is checked by default. The value inside the samples ratio (drop down menu) and the Subdivision amount (greyed out box) differ only in mathematical approach. They both determine how many paths are traced from the camera. Un-checking this box and manually insert-ing your own value is recommended, espe-cially if the secondary bounces require more attention.

The number of paths traced from the camera is the square of the subdivision value. 1000² equals 1 million paths. 2000² is 4 million and 10,000² is 100 million. The Samples Ratio values are based on the resolution of your scene. In the case of the 1/1 setting in a scene that’s 1280x720, the Light Cache would produce 0.9 million paths.

figure 3.25

In figure 3.25 I used a Sample ratio of 1/1 at 1280x720, implying 921,600 samples. The light cache took 28 seconds to compute

figure 3.26

In figure 3.26 I used a 960 samples in the Subdivision box. 960² = 921,600 samples. It should come as no surprise that the calcula-tion took exactly the same amount of time.

There are some instances where you’ll need to go beyond the 1/1 Samples ratio amount and manually enter Subdivision values. Though 1/2 is quite sufficient in most cases.

It is imperative to use a higher value during animation, but rare to exceed 4000. With scenes outside of the typical Physical Sun/Sky setup, where perhaps we’re using an abundance of light sources . The subdivision values will benefit from a boost.

figure 3.27

We’ve covered the essentials and I’ll provide a very brief explanation for the remaining settings.

Sample size determines the spacing of samples in the light cache. (Leave alone for now) Passes calculates the light cache separately on each thread of your cpu. (Useful for animation)

Store direct light. This option stores and interpolates direct light. This can be useful if you’re using and IR - LC setup. Use camera path. This is for tracing the Light cache along a camera path and is beneficial for animation.

Adaptive tracing. Stores additional infor-mation about incoming light for each light sample.

figure 3.28

Reconstruction parameters. These parameters control how the light cache is used in the final rendering, after it has been calculated.

Prefilter Checked on - Prefilter will be used. Prefilter is applied once the cache is com-puter or loaded from disc. Prefilter samples More prefilter samples equals a more blurry and less noisy cache.

Filter type. This is for tracing the Light cache along a camera path and is beneficial for animation.

Use light cache for glossy rays. If this option is on, the Light Cache is used to compute glossy rays as well normal GI rays. This option can speed up rendering of scene that have blurry reflections by a significant amount. Enable LC retrace. This option assists VRay in preventing light leaks at the expense of slightly increased calculation time in the IR Map.

Retrace threshold. This value can be used in conjunction with ‘use light cache for glossy rays’ to help VRay dynamically decide when and where to use the Light Cache.

Page 30 Page 31

Indirect Illumination - The Light Cache.The light cache (once again) is the approximation of global illumination in the scene. Spot3D.com “The light cache is built by tracing many eye paths from the camera.”

figure 3.24

I have to admit the first time I saw this menu, I felt a lot less threatened by it than I did the Irradiance map options.

In our current IR - LC setup we’re depending on the Light Cache portion of this solution to computer the secondary bounces.

In figure 3.24 the Overide LC subdivision box is checked by default. The value inside the samples ratio (drop down menu) and the Subdivision amount (greyed out box) differ only in mathematical approach. They both determine how many paths are traced from the camera. Un-checking this box and manually insert-ing your own value is recommended, espe-cially if the secondary bounces require more attention.

The number of paths traced from the camera is the square of the subdivision value. 1000² equals 1 million paths. 2000² is 4 million and 10,000² is 100 million. The Samples Ratio values are based on the resolution of your scene. In the case of the 1/1 setting in a scene that’s 1280x720, the Light Cache would produce 0.9 million paths.

figure 3.25

In figure 3.25 I used a Sample ratio of 1/1 at 1280x720, implying 921,600 samples. The light cache took 28 seconds to compute

figure 3.26

In figure 3.26 I used a 960 samples in the Subdivision box. 960² = 921,600 samples. It should come as no surprise that the calcula-tion took exactly the same amount of time.

There are some instances where you’ll need to go beyond the 1/1 Samples ratio amount and manually enter Subdivision values. Though 1/2 is quite sufficient in most cases.

It is imperative to use a higher value during animation, but rare to exceed 4000. With scenes outside of the typical Physical Sun/Sky setup, where perhaps we’re using an abundance of light sources . The subdivision values will benefit from a boost.

figure 3.27

We’ve covered the essentials and I’ll provide a very brief explanation for the remaining settings.

Sample size determines the spacing of samples in the light cache. (Leave alone for now) Passes calculates the light cache separately on each thread of your cpu. (Useful for animation)

Store direct light. This option stores and interpolates direct light. This can be useful if you’re using and IR - LC setup. Use camera path. This is for tracing the Light cache along a camera path and is beneficial for animation.

Adaptive tracing. Stores additional infor-mation about incoming light for each light sample.

figure 3.28

Reconstruction parameters. These parameters control how the light cache is used in the final rendering, after it has been calculated.

Prefilter Checked on - Prefilter will be used. Prefilter is applied once the cache is com-puter or loaded from disc. Prefilter samples More prefilter samples equals a more blurry and less noisy cache.

Filter type. This is for tracing the Light cache along a camera path and is beneficial for animation.

Use light cache for glossy rays. If this option is on, the Light Cache is used to compute glossy rays as well normal GI rays. This option can speed up rendering of scene that have blurry reflections by a significant amount. Enable LC retrace. This option assists VRay in preventing light leaks at the expense of slightly increased calculation time in the IR Map.

Retrace threshold. This value can be used in conjunction with ‘use light cache for glossy rays’ to help VRay dynamically decide when and where to use the Light Cache.

Page 32 Page 33

The DMC Sampler Having covered two of the possible GI engines and how their individual passes contribute towards the quality of the final render, we need to talk about the big guns! The DMC Sampler. You can think of the DMC sampler as a global quality control. This group of 4 settings play a very important role in the rest of the workflow.

figure 3.29

During render time, the DMC sampler is looking out to your scene for additional samples.

These rays are computed in such a way that if the values are too low, they will produce a noisy result. figure 3.30

figure 3.30

Values from almost every part of the render engine are coming in through this channel and being processed here.

Whenever you create a light, a blurry reflec-tion, use Depth of field or Motion Blur (to name a few), you’ve actually been providing the DMC sampler with more samples and infor-mation about the scene.

Looking at an Area light’s parameters (VRay Light tag), it reveals that the DMC sampler will be receiving 8 Subdivision samples from this light source. figure 3.31

The actual amount of samples, is the square of the subdivision value / 8² subdivisions = 64 samples

figure 3.31

The DMC Sampler can look at a series of these samples and determine that it has enough information to not use them all.

This is the role of the Adaptive amount. Let’s imagine the DMC sampler sees 100 samples for the entire scene. If we chose an adaptive amount of 0.8, the DMC sampler will always use 20 of those samples. The other 80% will be considered internally by the engine, but not necessarily used. Control over this function is decided by the “Early Termination Algorithm”

With an Adaptive amount of 1, we hand over control of all of the samples. (Fully adaptive) With an Adaptive amount of 0, All 100 samples will be used without consideration for the “Early Termination Algorithm”. (Not adaptive)

In most cases, the default value of 0.85 for the Adaptive amount is more than sufficient.

At 85% adaptive, this may seem like we’re leaving too much to chance, giving too much control to the DMC sampler. But VRay handles the process very smoothly and it’s not often necessary to go below 70% (0.7)

Noise Threshold. The Adaptive process communicates directly with the Noise Threshold amount. This value determines the amount of noise that is ac-ceptable before it can tun its attention to the next pixel in the calculation.

figure 3.35

figure 3.32 Noise threshold has a value of 0.01 figure 3.33 Noise threshold has a value of 0.1 figure 3.34 Noise threshold has a value of 1 A value between 0.01 and 0.004 is a good range for final renders. When the Noise Threshold is 1, the DMC sampler is satisfied that the desired amount of samples has been met while it’s still pro-ducing a very noisy value. This amounts to an incredibly fast, but noisy render. The DMC sampler frequently needs more samples from the external elements that are difficult to compute. A metal material that has blurry values (Glossiness subdivs) such as Brushed steel will often require more samples to achieve noise reduction and a quality result. Instead of trying to compensate for this in the DMC sampler, we would simply increase the Glossiness Subdivs value in the specular channel of the Vray Advanced material to a value higher than the default 8. figure 3.35

figure 3.32

figure 3.33

figure 3.34

Similarly, a single Area light that clearly stands out from the others as having too much visible noise, would also benefit from sending more samples to the DMC sampler.

Page 32 Page 33

The DMC Sampler Having covered two of the possible GI engines and how their individual passes contribute towards the quality of the final render, we need to talk about the big guns! The DMC Sampler. You can think of the DMC sampler as a global quality control. This group of 4 settings play a very important role in the rest of the workflow.

figure 3.29

During render time, the DMC sampler is looking out to your scene for additional samples.

These rays are computed in such a way that if the values are too low, they will produce a noisy result. figure 3.30

figure 3.30

Values from almost every part of the render engine are coming in through this channel and being processed here.

Whenever you create a light, a blurry reflec-tion, use Depth of field or Motion Blur (to name a few), you’ve actually been providing the DMC sampler with more samples and infor-mation about the scene.

Looking at an Area light’s parameters (VRay Light tag), it reveals that the DMC sampler will be receiving 8 Subdivision samples from this light source. figure 3.31

The actual amount of samples, is the square of the subdivision value / 8² subdivisions = 64 samples

figure 3.31

The DMC Sampler can look at a series of these samples and determine that it has enough information to not use them all.

This is the role of the Adaptive amount. Let’s imagine the DMC sampler sees 100 samples for the entire scene. If we chose an adaptive amount of 0.8, the DMC sampler will always use 20 of those samples. The other 80% will be considered internally by the engine, but not necessarily used. Control over this function is decided by the “Early Termination Algorithm”

With an Adaptive amount of 1, we hand over control of all of the samples. (Fully adaptive) With an Adaptive amount of 0, All 100 samples will be used without consideration for the “Early Termination Algorithm”. (Not adaptive)

In most cases, the default value of 0.85 for the Adaptive amount is more than sufficient.

At 85% adaptive, this may seem like we’re leaving too much to chance, giving too much control to the DMC sampler. But VRay handles the process very smoothly and it’s not often necessary to go below 70% (0.7)

Noise Threshold. The Adaptive process communicates directly with the Noise Threshold amount. This value determines the amount of noise that is ac-ceptable before it can tun its attention to the next pixel in the calculation.

figure 3.35

figure 3.32 Noise threshold has a value of 0.01 figure 3.33 Noise threshold has a value of 0.1 figure 3.34 Noise threshold has a value of 1 A value between 0.01 and 0.004 is a good range for final renders. When the Noise Threshold is 1, the DMC sampler is satisfied that the desired amount of samples has been met while it’s still pro-ducing a very noisy value. This amounts to an incredibly fast, but noisy render. The DMC sampler frequently needs more samples from the external elements that are difficult to compute. A metal material that has blurry values (Glossiness subdivs) such as Brushed steel will often require more samples to achieve noise reduction and a quality result. Instead of trying to compensate for this in the DMC sampler, we would simply increase the Glossiness Subdivs value in the specular channel of the Vray Advanced material to a value higher than the default 8. figure 3.35

figure 3.32

figure 3.33

figure 3.34

Similarly, a single Area light that clearly stands out from the others as having too much visible noise, would also benefit from sending more samples to the DMC sampler.

Page 34 Page 35

When a single object causes an issue, it’s im-portant to look at it’s individual subdivision parameters to resolve.

It would be a shame to spoil a good balanced rendering solution and shoot for an overall increase in quality on account of one prob-lematic object. This wouldn’t be a practical way to work. Looking again at figure 3.29 we have 2 settings remaining to talk about, and both of them at this point should be easy to comprehend.

figure 3.36Minimum Samples

Min samples equals the minimal amount of samples that the DMC sampler will compute before terminating the algorithm.

Note: The default 8 is once again squared to imply 64. It also intentionally matches the default number for all subdivision based parameters.

Global Subdivs multiplier. If an overall quality boost is required for every subdivision based parameter, this is a good place to dial in some numbers. The default value of 1 implies that every value will remain the same as the input value (for example: Glossiness Subdivs: 8) A increase to 1.5 would provide a 150% in-crease to all of these values. (Increasing the: Glossiness Subdivs: to 12)

I’m certain you’re all familiar with the practice of using Antialiasing in your scenes. VRay features 3 types of image samplers (antialiasing methods) and each one differs slightly in approach.

We have the Fixed rate sampler, the Adaptive DMC sampler and the Adaptive Subdivision sampler.

Choosing the right image sampler is determined by the individual scene and there are different consider-ations for each approach.

I’ve introduced you to 2 GI engines so far, the combination of which enables VRay to process your render. The IR + LC method is a popular choice and as an introduction to these practices was worth highlighting them side by side. Some other useful combinations are high-lighted in the presets. I.e; Lightcache +Bruteforce / IRradiance Map + Bruteforce.

Brute force computes every single shaded point separately and independently of other points, (while other approximation methods consider their neighbor in determining calculation). While highly accurate this method can also be very slow. The subdivision parameter here will also talk to the DMC sampler in the same way as discussed earlier.

Ray depth controls the number of bounces that will be computed, but is only available if Brute force is chosen as a secondary GI engine.

Photon maps are occasionally useful for in-teriors scenes, but this is an older method of approximation and I typically avoid it.

Spherical harmonics is not yet properly integrated into VRayForC4D and should be avoided.

Antialiasing Brute force, Photon maps, or Spherical harmonics.

Fixed Rate sampler figure 3.37

With this method, the sampler takes a fixed rate of samples per pixel. The subdivision value is squared as with other subdivision parameters. 1² =1 / 2²=4 / etc A value of 4 would indicate that 16 samples had been taken per pixel.

This sampler is simple and predictable in a broad range of antialiasing tasks, but the na-ture of a fixed sample can equal slow perfor-mance in some cases.

Note: Though not be ignored, I would recom-mend one of the other two choices based on my experiences with Fixed rate sampling.

figure 3.37 Adaptive DMC sampler figure 3.38

This sampler takes a variable number of samples per pixel based on a Min and Max rate.

It can also use the threshold set in the DMC sampler to determine if more samples are needed. (vs manual entry in Threshold amount)

This method is best for scenes that use a lot of blurry effects and is the preferred image sampler for DOF and Motion blur effects. Note: It is rare to have to increase the Min level higher than 1, other than scenes that are problematic.

Using Show Samples is a way to preview the antialiasing setup prior to final render.

figure 3.38

Page 34 Page 35

When a single object causes an issue, it’s im-portant to look at it’s individual subdivision parameters to resolve.

It would be a shame to spoil a good balanced rendering solution and shoot for an overall increase in quality on account of one prob-lematic object. This wouldn’t be a practical way to work. Looking again at figure 3.29 we have 2 settings remaining to talk about, and both of them at this point should be easy to comprehend.

figure 3.36Minimum Samples

Min samples equals the minimal amount of samples that the DMC sampler will compute before terminating the algorithm.

Note: The default 8 is once again squared to imply 64. It also intentionally matches the default number for all subdivision based parameters.

Global Subdivs multiplier. If an overall quality boost is required for every subdivision based parameter, this is a good place to dial in some numbers. The default value of 1 implies that every value will remain the same as the input value (for example: Glossiness Subdivs: 8) A increase to 1.5 would provide a 150% in-crease to all of these values. (Increasing the: Glossiness Subdivs: to 12)

I’m certain you’re all familiar with the practice of using Antialiasing in your scenes. VRay features 3 types of image samplers (antialiasing methods) and each one differs slightly in approach.

We have the Fixed rate sampler, the Adaptive DMC sampler and the Adaptive Subdivision sampler.

Choosing the right image sampler is determined by the individual scene and there are different consider-ations for each approach.

I’ve introduced you to 2 GI engines so far, the combination of which enables VRay to process your render. The IR + LC method is a popular choice and as an introduction to these practices was worth highlighting them side by side. Some other useful combinations are high-lighted in the presets. I.e; Lightcache +Bruteforce / IRradiance Map + Bruteforce.

Brute force computes every single shaded point separately and independently of other points, (while other approximation methods consider their neighbor in determining calculation). While highly accurate this method can also be very slow. The subdivision parameter here will also talk to the DMC sampler in the same way as discussed earlier.

Ray depth controls the number of bounces that will be computed, but is only available if Brute force is chosen as a secondary GI engine.

Photon maps are occasionally useful for in-teriors scenes, but this is an older method of approximation and I typically avoid it.

Spherical harmonics is not yet properly integrated into VRayForC4D and should be avoided.

Antialiasing Brute force, Photon maps, or Spherical harmonics.

Fixed Rate sampler figure 3.37

With this method, the sampler takes a fixed rate of samples per pixel. The subdivision value is squared as with other subdivision parameters. 1² =1 / 2²=4 / etc A value of 4 would indicate that 16 samples had been taken per pixel.

This sampler is simple and predictable in a broad range of antialiasing tasks, but the na-ture of a fixed sample can equal slow perfor-mance in some cases.

Note: Though not be ignored, I would recom-mend one of the other two choices based on my experiences with Fixed rate sampling.

figure 3.37 Adaptive DMC sampler figure 3.38

This sampler takes a variable number of samples per pixel based on a Min and Max rate.

It can also use the threshold set in the DMC sampler to determine if more samples are needed. (vs manual entry in Threshold amount)

This method is best for scenes that use a lot of blurry effects and is the preferred image sampler for DOF and Motion blur effects. Note: It is rare to have to increase the Min level higher than 1, other than scenes that are problematic.

Using Show Samples is a way to preview the antialiasing setup prior to final render.

figure 3.38

Page 36 Page 37

If you want VRay to create high quality images that don’t take forever to render, then we already have one thing in common.

To achieve this, I frequently tell my students that the best starting point is from lower/medium quality presets. From here you’ll be able to discern what part of the render needs your attention the most. Is it splotches on the walls? Then look to the IR map. Or are the walls fine and it’s some nuisance ornament with a bump map giving you grief? Then look to it’s material setting, the nearest light source, or better manage the antialiasing settings.

That may seem like a common sense approach, but if I got a dollar for every time somebody sent me a scene where they’d randomly entered 0.001 in the Noise Threshold to resolve a simple issue, I’d be rich! That value may well have fixed the issue, yet they inadvertently made the rest of the scene more compli-cated than it needed to be. On inspection it’s usually obvious that they were only trying to improve upon a couple of small problems. Similarly there’s a list of preset values known as “Universal VRay 1.5 Settings” that people rave about. You can see the appeal right away, although if you use these settings be open to the possibility of waiting around for a long time.

It’s my hope that I explained this process with relative clarity. If you do have any unresolved questions the VRayForC4D manual offers very precise examples of why each setting performs the way it does.

Wrapping up

figure 3.39

Adaptive Subdivision sampler figure 3.37

Of the 3 methods, this is the only sampler that can undersample (take less than 1 sample per pixel).

In scenes that don’t rely on blurry effects, this is the preferred image sampler for both its speed and reliability. However, in the presence of these effects it can perform worse than the DMC sampler.

See below for comparisons.

figure 3.40 - Using the Adaptive Subdivision sampler

figure 3.41 - Using the Adaptive DMC sampler

In the renders from figure 3.40 and figure 3.41 I’ve zoomed in to 800% to highlight the differ-ences between the Adaptive Subdivision sampler and the Adaptive DMC sampler.

The render times were seconds apart and the Min/Max settings identical (with no under sampling in the Adaptive SubD sampler)

The metallic device has a blurred metal surface and it’s clear that in this round, the Adaptive DMC sampler did a better job.

That’s not to suggest that the DMC sampler is always the clear winner. The reliability of Adaptive Subdivision sampler in the absence of blurry effects can add significant speed increases to your scenes and should not be overlooked. Experimentation is key.

Antialiasing filterIn VRay as with other render engines, Antialiasing filters can be applied. These are methods for sharpening or blurring values dependant on your needs.

These filters are integrated into the sampling process and do have an affect on render time. For example a sharpening filter like Catmull-rom and Mitchell-netravali may cost you a few additional seconds when compared to blurring filter like Box, Area and Gaussian and Area.

Note; These filters are not the same as apply-ing sharpening/blurring filters in post. I would recommend using one based on your needs at all times.

Page 36 Page 37

If you want VRay to create high quality images that don’t take forever to render, then we already have one thing in common.

To achieve this, I frequently tell my students that the best starting point is from lower/medium quality presets. From here you’ll be able to discern what part of the render needs your attention the most. Is it splotches on the walls? Then look to the IR map. Or are the walls fine and it’s some nuisance ornament with a bump map giving you grief? Then look to it’s material setting, the nearest light source, or better manage the antialiasing settings.

That may seem like a common sense approach, but if I got a dollar for every time somebody sent me a scene where they’d randomly entered 0.001 in the Noise Threshold to resolve a simple issue, I’d be rich! That value may well have fixed the issue, yet they inadvertently made the rest of the scene more compli-cated than it needed to be. On inspection it’s usually obvious that they were only trying to improve upon a couple of small problems. Similarly there’s a list of preset values known as “Universal VRay 1.5 Settings” that people rave about. You can see the appeal right away, although if you use these settings be open to the possibility of waiting around for a long time.

It’s my hope that I explained this process with relative clarity. If you do have any unresolved questions the VRayForC4D manual offers very precise examples of why each setting performs the way it does.

Wrapping up

figure 3.39

Adaptive Subdivision sampler figure 3.37

Of the 3 methods, this is the only sampler that can undersample (take less than 1 sample per pixel).

In scenes that don’t rely on blurry effects, this is the preferred image sampler for both its speed and reliability. However, in the presence of these effects it can perform worse than the DMC sampler.

See below for comparisons.

figure 3.40 - Using the Adaptive Subdivision sampler

figure 3.41 - Using the Adaptive DMC sampler

In the renders from figure 3.40 and figure 3.41 I’ve zoomed in to 800% to highlight the differ-ences between the Adaptive Subdivision sampler and the Adaptive DMC sampler.

The render times were seconds apart and the Min/Max settings identical (with no under sampling in the Adaptive SubD sampler)

The metallic device has a blurred metal surface and it’s clear that in this round, the Adaptive DMC sampler did a better job.

That’s not to suggest that the DMC sampler is always the clear winner. The reliability of Adaptive Subdivision sampler in the absence of blurry effects can add significant speed increases to your scenes and should not be overlooked. Experimentation is key.

Antialiasing filterIn VRay as with other render engines, Antialiasing filters can be applied. These are methods for sharpening or blurring values dependant on your needs.

These filters are integrated into the sampling process and do have an affect on render time. For example a sharpening filter like Catmull-rom and Mitchell-netravali may cost you a few additional seconds when compared to blurring filter like Box, Area and Gaussian and Area.

Note; These filters are not the same as apply-ing sharpening/blurring filters in post. I would recommend using one based on your needs at all times.

Page 38 Page 39

Chapter 4: Vray’s materialsWhatever your choice of render engine it’s good practice to have a test scene for trying out materials. In this chapter we’ll work with such an environment and introduce Vray’s BRDF material system.

figure 4.1

Open the scene file test_stage.c4d figure 4.1

figure 4.2

The scene uses three area lights and some basic geometry, it also renders very quickly for fast feedback.

Create from the materials manager, a new VRayBridge - VRay Advanced material

A VRay advanced material has far more options than a standard C4D mat. The vast majority of materials you’ll set up in VRay are relatively straight forward, though with this much flexibility, there’s a lot of room for complexity and creativity.

The material editor features many settings that you’re probably already familiar with Diffuse (color), Bump, Material weight (alpha), Luminosity layer (Luminance) and Specular layers (a mix of C4D’s reflection and secularity settings), Refraction layer (transparency)

There are 5 Specular layers in VRay, this allows for the creation of materials with more than one specular quality, such as varnished woods, car paints and some plastics. These layers contain options for both fake specular highlighting, or in the more physically correct way, which is to calculate specularity with glossy reflec-tions. Note: I’ve introduced you several times to the term Glossy. It simple implies blurry reflections, but is refereed to as ‘reflection glossiness’ in VRay. (See Specular layer parameters) In a Cinema 4D material, specularity and reflection are separate entities. In VRay there is the option to use the Reflection layer, though this is reserved for ob-jects with raw reflection like water and mirrors. It also doesn’t contain an option to include glossy reflections. Instead the Specular layer is where you’ll need to turn for the vast majority of your material reflectivity needs.

This layer contains options for a vast amount of specu-lar properties such as anisotropic surfaces, blurry me-tallic surfaces and precise control with fresnel effects (reflection viewing angle). figure 4.4

figure 4.3

Specular layers

figure 4.5

In figure 4.5

Sphere A, the Vray Material is tracing only the fake specular values.

Sphere B, is tracing both fake specular and blurry reflections.

Sphere C, is tracing blurry reflections only.

Note: In the real world, almost every object contains at least some specularity.

figure 4.4

‘VrayAdvancedMaterial’

Page 38 Page 39

Chapter 4: Vray’s materialsWhatever your choice of render engine it’s good practice to have a test scene for trying out materials. In this chapter we’ll work with such an environment and introduce Vray’s BRDF material system.

figure 4.1

Open the scene file test_stage.c4d figure 4.1

figure 4.2

The scene uses three area lights and some basic geometry, it also renders very quickly for fast feedback.

Create from the materials manager, a new VRayBridge - VRay Advanced material

A VRay advanced material has far more options than a standard C4D mat. The vast majority of materials you’ll set up in VRay are relatively straight forward, though with this much flexibility, there’s a lot of room for complexity and creativity.

The material editor features many settings that you’re probably already familiar with Diffuse (color), Bump, Material weight (alpha), Luminosity layer (Luminance) and Specular layers (a mix of C4D’s reflection and secularity settings), Refraction layer (transparency)

There are 5 Specular layers in VRay, this allows for the creation of materials with more than one specular quality, such as varnished woods, car paints and some plastics. These layers contain options for both fake specular highlighting, or in the more physically correct way, which is to calculate specularity with glossy reflec-tions. Note: I’ve introduced you several times to the term Glossy. It simple implies blurry reflections, but is refereed to as ‘reflection glossiness’ in VRay. (See Specular layer parameters) In a Cinema 4D material, specularity and reflection are separate entities. In VRay there is the option to use the Reflection layer, though this is reserved for ob-jects with raw reflection like water and mirrors. It also doesn’t contain an option to include glossy reflections. Instead the Specular layer is where you’ll need to turn for the vast majority of your material reflectivity needs.

This layer contains options for a vast amount of specu-lar properties such as anisotropic surfaces, blurry me-tallic surfaces and precise control with fresnel effects (reflection viewing angle). figure 4.4

figure 4.3

Specular layers

figure 4.5

In figure 4.5

Sphere A, the Vray Material is tracing only the fake specular values.

Sphere B, is tracing both fake specular and blurry reflections.

Sphere C, is tracing blurry reflections only.

Note: In the real world, almost every object contains at least some specularity.

figure 4.4

‘VrayAdvancedMaterial’

Page 40 Page 41

For our first material, lets activate a single Specular Layer and leave everything as de-fault. Apply the material to the sphere object and perform a quick render test. figure 4.6

figure 4.6

In the setting Specular Layer Transparency, change the amount to 50% and test again.

figure 4.7

The reduction of transparency has allowed for more of the reflection from this layer to show. figure 4.7

For the next stage of this material test, add another Vray advanced material and in the diffuse channel only, add a blue color. Apply this new material to the cube object.

Now returning to the first materials Specular layer. Scroll down to reflection glossiness and add a value of 0.8. figure 4.8

figure 4.8

figure 4.9

A rendered results should now show a metal like material that’s been processed with both fake specularity and glossy reflections. figure 4.9

figure 4.10

At the top of the Specular layer settings is an option for Specular Type. Change this from Phong to Ward. The result should now look like figure 4.10

Each Specular Types computes in a unique way and provides different results. Blinn and Ward are good choices for metallic effects and they also render Anisotropic effects more accurately.

Back in the Specular layer settings change the Anisotropy value to 0.5

figure 4.11

The result figure 4.11 is not quite yet a Brushed metal, but we’re establishing the workflow in ordered to create one.

For the next step, return to the Diffuse layer (remaining within the metal material) and reduce the Diffuse Color - Brightness amount to 20%.

Back to the Specular layer scroll all the way down to the last few settings and Check the Use Fresnel box and input 22 for Fresnel IOR(Index of refraction)

You will now notice that the Specular Layer Transparency option is no longer available. This is because we’re using IOR to determine reflectivity.

In the Specular color at the top, add a Fresnel shader to the texture map slot. figure 4.12 In the shader settings, reduce the black to a light grey. This will prevent the scratched surface from reaching the sphere’s edges.

figure 4.12

Lower the Anisotropy amount back to 0 and in the Texture map slot below load in the texture ‘HT_Brushed.png’ from the textures folder. Repeat this process as illustrated below in figure 4.13 - while also checking the invert box where appropriate.

figure 4.13

Page 40 Page 41

For our first material, lets activate a single Specular Layer and leave everything as de-fault. Apply the material to the sphere object and perform a quick render test. figure 4.6

figure 4.6

In the setting Specular Layer Transparency, change the amount to 50% and test again.

figure 4.7

The reduction of transparency has allowed for more of the reflection from this layer to show. figure 4.7

For the next stage of this material test, add another Vray advanced material and in the diffuse channel only, add a blue color. Apply this new material to the cube object.

Now returning to the first materials Specular layer. Scroll down to reflection glossiness and add a value of 0.8. figure 4.8

figure 4.8

figure 4.9

A rendered results should now show a metal like material that’s been processed with both fake specularity and glossy reflections. figure 4.9

figure 4.10

At the top of the Specular layer settings is an option for Specular Type. Change this from Phong to Ward. The result should now look like figure 4.10

Each Specular Types computes in a unique way and provides different results. Blinn and Ward are good choices for metallic effects and they also render Anisotropic effects more accurately.

Back in the Specular layer settings change the Anisotropy value to 0.5

figure 4.11

The result figure 4.11 is not quite yet a Brushed metal, but we’re establishing the workflow in ordered to create one.

For the next step, return to the Diffuse layer (remaining within the metal material) and reduce the Diffuse Color - Brightness amount to 20%.

Back to the Specular layer scroll all the way down to the last few settings and Check the Use Fresnel box and input 22 for Fresnel IOR(Index of refraction)

You will now notice that the Specular Layer Transparency option is no longer available. This is because we’re using IOR to determine reflectivity.

In the Specular color at the top, add a Fresnel shader to the texture map slot. figure 4.12 In the shader settings, reduce the black to a light grey. This will prevent the scratched surface from reaching the sphere’s edges.

figure 4.12

Lower the Anisotropy amount back to 0 and in the Texture map slot below load in the texture ‘HT_Brushed.png’ from the textures folder. Repeat this process as illustrated below in figure 4.13 - while also checking the invert box where appropriate.

figure 4.13

Page 42 Page 43

We’ve provided VRay with enough informa-tion to produce a semi-realistic scratched metal surface. Work can be done in the bump map channel to bring out extra details and a lot of time can be spent tweaking the values for a perfect result.

Note: The reason behind the inverted texture map in the Glossiness reflection is that in real-ity, the deeper the scratch, the more blurry its reflectivity would become.

The result in figure 4.14 is far from complete, yet you have a good starting point from which to experiment further.

figure 4.14

Using a similar technique in figure 4.15 to cre-ate a Galvanized metal, the differences in blurry values vs more reflective values are obvious.

figure 4.15

The Diffuse layer You may have noticed that in the Specular settings I increased the Glossiness SubDivi-sion amount up to 30.

As discussed in the section on VRay’s DMC sampler, this is an example of where the material needs to send out more samples in order to be computed with less noise. Keep in mind that these sorts of materials are usually quite render intensive.

There are two Diffuse layers in the Vray advanced material, these are useful for mixing diffuse (color/tex-ture) effects without resorting to separate materials.

VRay Dirt is also accessible through the Diffuse layer. By applying Ambient occlusion at the material level this option creates the appearance of dirt on the surface details of an object.

The Diffuse layer Transparency option serves two functions, it is first required to let the underlying layer show (Diffuse layer 2) and is also required to use the Fast SSS shader option (see page 57)

figure 4.16 ‘VRay Goldman’

In both figure 4.16 and figure 4.17 you can see the vast amount of flexibility available to you in the Specular layer channel.

figure 4.17 “The Weasley’s’ figure 4.18

Open example file scene test_stage2.c4dCreate a new Vray advanced material and apply to the sphere object.

In Diffuse layer 1 check from the Diffuse op-tions - Use VRayDirt.

The menu layout will now change to the VRayDirt workflow.

Add a black Color channel to the Occluded color slot (from the drop down menu)

Add an 80% white Color channel to the Occluded color slot (from the drop down menu)

figure 4.19

In figure 4.18 the result has been intentionally enhanced to show the overall effect.

Any color combination can be used to achieve the desired look. In figure 4.20, I’m using a wood texture as the Unoccluded color and Red for the Occluded color (Dirt effect).

figure 4.20

‘VrayAdvancedMaterial’

Page 42 Page 43

We’ve provided VRay with enough informa-tion to produce a semi-realistic scratched metal surface. Work can be done in the bump map channel to bring out extra details and a lot of time can be spent tweaking the values for a perfect result.

Note: The reason behind the inverted texture map in the Glossiness reflection is that in real-ity, the deeper the scratch, the more blurry its reflectivity would become.

The result in figure 4.14 is far from complete, yet you have a good starting point from which to experiment further.

figure 4.14

Using a similar technique in figure 4.15 to cre-ate a Galvanized metal, the differences in blurry values vs more reflective values are obvious.

figure 4.15

The Diffuse layer You may have noticed that in the Specular settings I increased the Glossiness SubDivi-sion amount up to 30.

As discussed in the section on VRay’s DMC sampler, this is an example of where the material needs to send out more samples in order to be computed with less noise. Keep in mind that these sorts of materials are usually quite render intensive.

There are two Diffuse layers in the Vray advanced material, these are useful for mixing diffuse (color/tex-ture) effects without resorting to separate materials.

VRay Dirt is also accessible through the Diffuse layer. By applying Ambient occlusion at the material level this option creates the appearance of dirt on the surface details of an object.

The Diffuse layer Transparency option serves two functions, it is first required to let the underlying layer show (Diffuse layer 2) and is also required to use the Fast SSS shader option (see page 57)

figure 4.16 ‘VRay Goldman’

In both figure 4.16 and figure 4.17 you can see the vast amount of flexibility available to you in the Specular layer channel.

figure 4.17 “The Weasley’s’ figure 4.18

Open example file scene test_stage2.c4dCreate a new Vray advanced material and apply to the sphere object.

In Diffuse layer 1 check from the Diffuse op-tions - Use VRayDirt.

The menu layout will now change to the VRayDirt workflow.

Add a black Color channel to the Occluded color slot (from the drop down menu)

Add an 80% white Color channel to the Occluded color slot (from the drop down menu)

figure 4.19

In figure 4.18 the result has been intentionally enhanced to show the overall effect.

Any color combination can be used to achieve the desired look. In figure 4.20, I’m using a wood texture as the Unoccluded color and Red for the Occluded color (Dirt effect).

figure 4.20

‘VrayAdvancedMaterial’

Page 44 Page 45

Refraction Layer

The Refraction layer is for the creation of optically transparent materials.

This layer can assist in the creation of standard glass, gems, fluids, complex translucent effects, frosted glass and much more. It’s parameters contain options for the accurate calculation of Absorption, Blurry effects, Dispersion and Sub Surface Scattering.

figure 4.12 - Color enhanced

Open example file test_stage_glass.c4d

Create a new Vray advanced material and apply to the glass object.

Deactivate the Diffuse layer and activate a Refraction layer. Check Specular layer 1 without making any changes. Render

Without any changes to the default settings, the Refraction layer provides us with a glass material with an IOR (index of refraction) of 1.6

Adding a Specular layer to a glass material is common practice, as glass always includes some amount of reflectivity.

In the Refraction layer look towards the Volume Fog parameters and check Enable Volume.

Leave the Emission color as default black and chose a very light orange/yellow for the Volume Color. Finally increase the amount to 0.3 and render.

figure 4.13

figure 4.14 - Color enhanced

This effect has added absorption properties to the glass and it now has the appearance of greater volume.

To simulate frosted glass, we would enter a Glossiness value (0.6 in this example) in the Refraction layer. As shown in figure 4.15 Variation in the frosted amount can be achieved by using the Glossiness Texture map slot.

figure 4.15 - Color enhanced

Note: These effects can add significantly to your render time and often require additional subdivision values to render accurately.

The images below contain different examples of Glossiness effects in the Refraction layer.

figure 4.16 ‘Visa’ product shot

figure 4.17 ‘Go Beyond’

It is also possible to use the SSS parameters from the Refraction layer to simulate the translucent properties of hard wax, honey, plastics and other surfaces that depend more on refraction for accurate results.

The example from figure 4.19 uses the follow-ing setup. figure 4.18

figure 4.19

figure 4.18

Note; To speed up the SSS calculation check ‘Environment fog’ in the SSS parameters. This stores the light directly in the volume.

‘VrayAdvancedMaterial’

Page 44 Page 45

Refraction Layer

The Refraction layer is for the creation of optically transparent materials.

This layer can assist in the creation of standard glass, gems, fluids, complex translucent effects, frosted glass and much more. It’s parameters contain options for the accurate calculation of Absorption, Blurry effects, Dispersion and Sub Surface Scattering.

figure 4.12 - Color enhanced

Open example file test_stage_glass.c4d

Create a new Vray advanced material and apply to the glass object.

Deactivate the Diffuse layer and activate a Refraction layer. Check Specular layer 1 without making any changes. Render

Without any changes to the default settings, the Refraction layer provides us with a glass material with an IOR (index of refraction) of 1.6

Adding a Specular layer to a glass material is common practice, as glass always includes some amount of reflectivity.

In the Refraction layer look towards the Volume Fog parameters and check Enable Volume.

Leave the Emission color as default black and chose a very light orange/yellow for the Volume Color. Finally increase the amount to 0.3 and render.

figure 4.13

figure 4.14 - Color enhanced

This effect has added absorption properties to the glass and it now has the appearance of greater volume.

To simulate frosted glass, we would enter a Glossiness value (0.6 in this example) in the Refraction layer. As shown in figure 4.15 Variation in the frosted amount can be achieved by using the Glossiness Texture map slot.

figure 4.15 - Color enhanced

Note: These effects can add significantly to your render time and often require additional subdivision values to render accurately.

The images below contain different examples of Glossiness effects in the Refraction layer.

figure 4.16 ‘Visa’ product shot

figure 4.17 ‘Go Beyond’

It is also possible to use the SSS parameters from the Refraction layer to simulate the translucent properties of hard wax, honey, plastics and other surfaces that depend more on refraction for accurate results.

The example from figure 4.19 uses the follow-ing setup. figure 4.18

figure 4.19

figure 4.18

Note; To speed up the SSS calculation check ‘Environment fog’ in the SSS parameters. This stores the light directly in the volume.

‘VrayAdvancedMaterial’

Page 46 Page 47

SSS calculated as part of the refraction layer (as shown on page 45) is an accurate representation of a real world translucent effect. While it can produce stunning results, it can also be notoriously slow to render. A much faster approach is to use a VRayFastSSS2 material. The parameters of which are available as an extension of the standard VRay Advanced material and as a standalone material called the VRayFastSSS2 material.

It’s also possible to cheat translucent effects using the Vray2Sided material. (which we’ll cover on page 48)

The majority of your translucent material needs should be met by the Fast SSS option.

Sub Surface Scattering

figure 4.20

Open example file test_stage_candle.c4d

In this scene I’ve simply added a VRay-FastSSS material to the cylinder shape, made a couple of adjustment to color and added a texture map.

The result figure 4.20 shows a subtle hint of translucency.

In the VRayFastSSS material settings, scroll down to options and change the Single Scat-ter parameter from to Simple to Raytraced-refractive. figure 4.21

figure 4.21

figure 4.22

The rendered result is now noticeably differ-ent. figure 4.22

The original Simple mode approximated translucency from the surface lighting alone. The Raytraced-Refractive mode traces the refraction amount based on the provided IOR.

Also notice that when VRay is computing Fast SSS, it’s also adding an additional dark pass that appears to isolate the translucent effects. This is a special pass called the Illumination map. It can be controlled in the prepass rate which is set to -1 by default. For higher res images, a value of 0 is occasionally needed.

This time we’ll use the SSS layer in the VRay Advanced material to make a semi accurate portrayal of a marble floor.

Open example file test_stage_marble.c4d

The scene is setup with a marble texture map and contains only a Diffuse layer.

In the Diffuse Layer change the Diffuse Layer Transparency to 40%. This will allow underlying effects such as the SSS layer to mix with the Diffuse Layer at the inputted value.

At 100% transparency, this Diffuse layer would no longer render at all.

Activate the SSS Layer and try to match the three shades of green from figure 4.24

figure 4.23

figure 4.24

Change the Single Scatter parameter from to Simple to Raytraced-Solid. figure 4.21

The Raytraced-Solid mode will calculate/es-timate the Volume inside the object.

The material is starting to look a little better, but it’s missing glossy reflections and a bump map.

Activate a Specular Layer , check Use Fresnel and input a value of 1.6 for the Fresnel IOR amount. Next, input a Reflection Glossiness value of .095

Activate Bump and copy the Diffuse Layer texture into this channel.

With no real bump information, you can increase the value to 3. Though this is not a practical approach for most materials.

The result is far from perfect, but suffice to say it created the desired affect. figure 4.25

figure 4.25

figure 4.26

‘VrayAdvancedMaterial’ and ‘VRayFastSSS2 Material’

Page 46 Page 47

SSS calculated as part of the refraction layer (as shown on page 45) is an accurate representation of a real world translucent effect. While it can produce stunning results, it can also be notoriously slow to render. A much faster approach is to use a VRayFastSSS2 material. The parameters of which are available as an extension of the standard VRay Advanced material and as a standalone material called the VRayFastSSS2 material.

It’s also possible to cheat translucent effects using the Vray2Sided material. (which we’ll cover on page 48)

The majority of your translucent material needs should be met by the Fast SSS option.

Sub Surface Scattering

figure 4.20

Open example file test_stage_candle.c4d

In this scene I’ve simply added a VRay-FastSSS material to the cylinder shape, made a couple of adjustment to color and added a texture map.

The result figure 4.20 shows a subtle hint of translucency.

In the VRayFastSSS material settings, scroll down to options and change the Single Scat-ter parameter from to Simple to Raytraced-refractive. figure 4.21

figure 4.21

figure 4.22

The rendered result is now noticeably differ-ent. figure 4.22

The original Simple mode approximated translucency from the surface lighting alone. The Raytraced-Refractive mode traces the refraction amount based on the provided IOR.

Also notice that when VRay is computing Fast SSS, it’s also adding an additional dark pass that appears to isolate the translucent effects. This is a special pass called the Illumination map. It can be controlled in the prepass rate which is set to -1 by default. For higher res images, a value of 0 is occasionally needed.

This time we’ll use the SSS layer in the VRay Advanced material to make a semi accurate portrayal of a marble floor.

Open example file test_stage_marble.c4d

The scene is setup with a marble texture map and contains only a Diffuse layer.

In the Diffuse Layer change the Diffuse Layer Transparency to 40%. This will allow underlying effects such as the SSS layer to mix with the Diffuse Layer at the inputted value.

At 100% transparency, this Diffuse layer would no longer render at all.

Activate the SSS Layer and try to match the three shades of green from figure 4.24

figure 4.23

figure 4.24

Change the Single Scatter parameter from to Simple to Raytraced-Solid. figure 4.21

The Raytraced-Solid mode will calculate/es-timate the Volume inside the object.

The material is starting to look a little better, but it’s missing glossy reflections and a bump map.

Activate a Specular Layer , check Use Fresnel and input a value of 1.6 for the Fresnel IOR amount. Next, input a Reflection Glossiness value of .095

Activate Bump and copy the Diffuse Layer texture into this channel.

With no real bump information, you can increase the value to 3. Though this is not a practical approach for most materials.

The result is far from perfect, but suffice to say it created the desired affect. figure 4.25

figure 4.25

figure 4.26

‘VrayAdvancedMaterial’ and ‘VRayFastSSS2 Material’

Page 48 Page 49

VRay2Sided Material Making a ‘lamp shade’ with the bulb obscured behind a layer of fabric (as in figure 4.27) used to be a dif-ficult task to accomplish. Fully opaque materials simply weren’t designed to transmit light through their surface in this way. Adding Diffuse layer transparency (or alpha in C4D) didn’t help matters either, as a percentage of the light would simply pass through the volume.

The VRay2Sided material solves this old limitation by allowing us to have a ‘diffuser’ in VRay. A diffuser softens light as it passes through a surface, essentially making it what we call translucent. This material was created to address the need for thin translucent objects like paper, leaves, fabrics, dif-fusers etc, but its application can be much more experimental.

In figure 4.27 ‘the lamp shade’ object highlights an example of how this material was intended to work. Illumination from within the object passes through the material via translucency and displays the result on the front facing normals.

The VRay2Sided material is controlled by two standard diffuse materials (VRayAdvanced material) for the front/back facing normals and a Translucency color to determine how much of the effect should come through.

The VRay2Sided material in figure 4.28 features reflective properties on its front side. A separate object with a colored pattern light has been placed within the dragon model (via the Luminosity layer) and the result creates a glowing translucent effect. This behavior looks closer to a refractive SSS solution, but is actually cheated as the light is emitted from the inside only. Of course cheating in 3D is never a bad thing.

In figure 4.29 I’m using the same approach but on a much bigger scale. This time I’ve placed uniquely col-ored light objects within each skyscraper. The Luminosity layer casts its rays outwards and are intended to fake the lighting that would have otherwise come from a traditional lighting solution. This was a test scene, but also a very practical solution for visualizing cities at a distance.

figure 4.31

Open example file scene 2_sided_user.c4d

This simple setup has an area light, a thin plane object, a couple of props and currently no materials. figure 4.30

figure 4.30

If we the render the shot directly, you’ll see that the plane object is obscuring the light.figure 4.31

Add a VRay2Sided material and apply it to the plane without any additional changes, and it will now render a simple diffuser. figure 4.32

figure 4.32

The light has now penetrated the object as determined by the parameters in the VRay-2Sided material.

Leaving the front and back side options of the VRay2Sided material free of supporting materials was a deliberate move. It illustrates that in the absence of a material channel, the VRay2Sided material will use a standard grey diffuse VRayAdvanced material by default. Additional control is provided by the Trans-lucency color setting. By default it is set to 50% grey which would allow an equal amount of the front and back to show (depen-dent upon illumination values). To let more of the Back side material show through, push the color closer to white. To retain more of the Front side material, bring it closer to black.

You can also use color or a Translucency texture for experimenting with different translucent effects.

In the example file scene 2_sided_spherelamp.c4dyou’ll find the following example figure 4.33 and other experiments from my collection.

figure 4.33

Note: In order for the Front side material to show at all, it must be illuminated from the front. It’s a com-mon mistake to light only from the rear and expect the front side to show.figure 4.27 figure 4.28 figure 4.29

Standalone material

Page 48 Page 49

VRay2Sided Material Making a ‘lamp shade’ with the bulb obscured behind a layer of fabric (as in figure 4.27) used to be a dif-ficult task to accomplish. Fully opaque materials simply weren’t designed to transmit light through their surface in this way. Adding Diffuse layer transparency (or alpha in C4D) didn’t help matters either, as a percentage of the light would simply pass through the volume.

The VRay2Sided material solves this old limitation by allowing us to have a ‘diffuser’ in VRay. A diffuser softens light as it passes through a surface, essentially making it what we call translucent. This material was created to address the need for thin translucent objects like paper, leaves, fabrics, dif-fusers etc, but its application can be much more experimental.

In figure 4.27 ‘the lamp shade’ object highlights an example of how this material was intended to work. Illumination from within the object passes through the material via translucency and displays the result on the front facing normals.

The VRay2Sided material is controlled by two standard diffuse materials (VRayAdvanced material) for the front/back facing normals and a Translucency color to determine how much of the effect should come through.

The VRay2Sided material in figure 4.28 features reflective properties on its front side. A separate object with a colored pattern light has been placed within the dragon model (via the Luminosity layer) and the result creates a glowing translucent effect. This behavior looks closer to a refractive SSS solution, but is actually cheated as the light is emitted from the inside only. Of course cheating in 3D is never a bad thing.

In figure 4.29 I’m using the same approach but on a much bigger scale. This time I’ve placed uniquely col-ored light objects within each skyscraper. The Luminosity layer casts its rays outwards and are intended to fake the lighting that would have otherwise come from a traditional lighting solution. This was a test scene, but also a very practical solution for visualizing cities at a distance.

figure 4.31

Open example file scene 2_sided_user.c4d

This simple setup has an area light, a thin plane object, a couple of props and currently no materials. figure 4.30

figure 4.30

If we the render the shot directly, you’ll see that the plane object is obscuring the light.figure 4.31

Add a VRay2Sided material and apply it to the plane without any additional changes, and it will now render a simple diffuser. figure 4.32

figure 4.32

The light has now penetrated the object as determined by the parameters in the VRay-2Sided material.

Leaving the front and back side options of the VRay2Sided material free of supporting materials was a deliberate move. It illustrates that in the absence of a material channel, the VRay2Sided material will use a standard grey diffuse VRayAdvanced material by default. Additional control is provided by the Trans-lucency color setting. By default it is set to 50% grey which would allow an equal amount of the front and back to show (depen-dent upon illumination values). To let more of the Back side material show through, push the color closer to white. To retain more of the Front side material, bring it closer to black.

You can also use color or a Translucency texture for experimenting with different translucent effects.

In the example file scene 2_sided_spherelamp.c4dyou’ll find the following example figure 4.33 and other experiments from my collection.

figure 4.33

Note: In order for the Front side material to show at all, it must be illuminated from the front. It’s a com-mon mistake to light only from the rear and expect the front side to show.figure 4.27 figure 4.28 figure 4.29

Standalone material

Page 50 Page 51

In this short tutorial, I’ll guide you through the workflow needed to make the fake SSS effect used on the Dragon figure 4.28 (on Page 48) Open example file 2_sided_buddha.c4d

figure 4.34

The scene figure 4.34 has a the Buddha figure and three primitive objects tucked neatly inside his body. Create a VRayAdvanced material and add a Luminosity layer. Apply a blue Luminos-ity color, leave at 100% for brightness and add a value of 10 in the second box labeled Amount In Luminosity Layer parameters check Compensate exposure. Note: We’ll be covering Luminosity on the next page.

figure 4.35

Name this material ‘backlight’ and apply it to the Null object called ‘Internal’ - We now have an internal lighting solution for the Buddha figure.

Create a new VRayAdvanced material and name it ‘Outside’ In Diffuse Layer 1 check Use VRayDirt

Add dark blue for the Occluded color via a color channel. (See page 43 for help)

Add a light blue for the Unoccluded color via a color channel. (See page 43 for help)

Finally add Specular layer 1 and make no ad-ditional changes.

Next, create a VRay2Sided material and add the material called ‘Outside’ to the front side material option of the VRay2Sided material. figure 4.36

Finally apply the VRay2Sided material to the ‘Buddha’ figure and Render. figure 4.37

This backlit fake SSS effect has countless uses and of course, it looks kinda cool!

figure 4.36

figure 4.37

VRayBlendMaterial

The VRayBlendMaterial allows you to stack materials - It works in almost exactly the same way as manu-ally stacking them in the object manager, but allows for better management in some cases.

The process starts off with a base layer such a brick map for example, then additional materials are ap-plied as a coat material, this could be useful for peeling paint of a layer of broken concrete. Various mapping techniques that have some Material weight (alpha) or Diffuse Layer transparency are useful in determining to what degree the underlying material is seen.

Below are some examples of materials that have been layered with this technique. In figure 4.38 an underlying rock material is coated with a slightly translucent coating of snow.

In figure 4.39 glass is affected by a fiery layer and covered with a dusting of sand.

In figure 4.28 an organic rock is coated with a glow based effect based off a vertex map selection.

All very straight forward, but with amazing amounts of potential.

figure 4.38 figure 4.39 figure 4.40

Layering shader - Standalone

Note: These files are all available in the VrayBlendMaterial folder.

Page 50 Page 51

In this short tutorial, I’ll guide you through the workflow needed to make the fake SSS effect used on the Dragon figure 4.28 (on Page 48) Open example file 2_sided_buddha.c4d

figure 4.34

The scene figure 4.34 has a the Buddha figure and three primitive objects tucked neatly inside his body. Create a VRayAdvanced material and add a Luminosity layer. Apply a blue Luminos-ity color, leave at 100% for brightness and add a value of 10 in the second box labeled Amount In Luminosity Layer parameters check Compensate exposure. Note: We’ll be covering Luminosity on the next page.

figure 4.35

Name this material ‘backlight’ and apply it to the Null object called ‘Internal’ - We now have an internal lighting solution for the Buddha figure.

Create a new VRayAdvanced material and name it ‘Outside’ In Diffuse Layer 1 check Use VRayDirt

Add dark blue for the Occluded color via a color channel. (See page 43 for help)

Add a light blue for the Unoccluded color via a color channel. (See page 43 for help)

Finally add Specular layer 1 and make no ad-ditional changes.

Next, create a VRay2Sided material and add the material called ‘Outside’ to the front side material option of the VRay2Sided material. figure 4.36

Finally apply the VRay2Sided material to the ‘Buddha’ figure and Render. figure 4.37

This backlit fake SSS effect has countless uses and of course, it looks kinda cool!

figure 4.36

figure 4.37

VRayBlendMaterial

The VRayBlendMaterial allows you to stack materials - It works in almost exactly the same way as manu-ally stacking them in the object manager, but allows for better management in some cases.

The process starts off with a base layer such a brick map for example, then additional materials are ap-plied as a coat material, this could be useful for peeling paint of a layer of broken concrete. Various mapping techniques that have some Material weight (alpha) or Diffuse Layer transparency are useful in determining to what degree the underlying material is seen.

Below are some examples of materials that have been layered with this technique. In figure 4.38 an underlying rock material is coated with a slightly translucent coating of snow.

In figure 4.39 glass is affected by a fiery layer and covered with a dusting of sand.

In figure 4.28 an organic rock is coated with a glow based effect based off a vertex map selection.

All very straight forward, but with amazing amounts of potential.

figure 4.38 figure 4.39 figure 4.40

Layering shader - Standalone

Note: These files are all available in the VrayBlendMaterial folder.

Page 52 Page 53

VRayDisplaceMaterial The VRayDisplaceMaterial allows the usage of Displacement maps in VRay.

It’s possible to mix this material with a standard VRayAdvancedMaterial by stacking it to the right of the standard material and choosing ‘Mix textures’ from the texture tag. Let’s quickly explore.

The following example uses the Displacement type: 3D Mapping, which is suited to procedural effects.

Open example file displacement_user.c4d

figure 4.38

Create a standard VRayAdvanced material and apply it to the cube. Create a VRayDisplaceMaterial and also apply to the cube object (after the first mate-rial)

Select the VRayDisplaceMaterial tag from the object manager and check Mix Textures figure 4.39

figure 4.39

In the VRayDisplaceMaterial’s texture path, add a noise channel from the drop down menu. Click the noise channel and change the type to ‘Cel noise’, finally increase the Global scale value to 250%. In the VRayDisplaceMaterial’s parameterschange the amount to 10cm and check the box Keep contunity. Render. figure 4.40

figure 4.40

In figure 4.41 I’ve copied the ‘Cel noise’ to the VRayAdvancedMaterial’s diffuse channel, created a couple of layers with some noise variation and have used VRayDirt (page 43) See file displacement_example .c4d

figure 4.40

Use Cubic projection (for both)

Check Mix textures

Select VrayDisplacement material.

The Displacement type: 2D Mapping, is used when an image based displacement map is available. With this workflow, you can maintain a low polygon count and depend on the displacement map to give the appearance of millions of polygons at a sub polygon level.

In examples figure 4.31 - figure 4.32 the rendered results shows that although the original model only had 68,000 polygons, they’ve been effectively turned to 3.4 million poly-gons with a displacement map.

figure 4.31 ‘Octopus’

Parameters.

The amount value (in both the 3D and 2D options) control the maximum height of the displace-ment map. The shift value specifies a constant amount that the polygons will be shifted relative to their normal position.

While Use default parameters is checked, the resolution for 3D displacement is controlled via the VRayBridge settings under Displace-ment.

The default amount can be set too high for certain tasks and should be experimented with for optimal results.

For more in depth features relating to your displacement needs, please refer to the VRay manual. Note: It’s still possible to add a VRayDisplace-ment Tag from the object manager, although this is the old workflow and only remains available for Legacy reasons (to support older files).

figure 4.42 (zoomed in)

figure 4.43 (zoomed in)

figure 4.33 -is the 16 bit tif image used to create the displacement.

Page 52 Page 53

VRayDisplaceMaterial The VRayDisplaceMaterial allows the usage of Displacement maps in VRay.

It’s possible to mix this material with a standard VRayAdvancedMaterial by stacking it to the right of the standard material and choosing ‘Mix textures’ from the texture tag. Let’s quickly explore.

The following example uses the Displacement type: 3D Mapping, which is suited to procedural effects.

Open example file displacement_user.c4d

figure 4.38

Create a standard VRayAdvanced material and apply it to the cube. Create a VRayDisplaceMaterial and also apply to the cube object (after the first mate-rial)

Select the VRayDisplaceMaterial tag from the object manager and check Mix Textures figure 4.39

figure 4.39

In the VRayDisplaceMaterial’s texture path, add a noise channel from the drop down menu. Click the noise channel and change the type to ‘Cel noise’, finally increase the Global scale value to 250%. In the VRayDisplaceMaterial’s parameterschange the amount to 10cm and check the box Keep contunity. Render. figure 4.40

figure 4.40

In figure 4.41 I’ve copied the ‘Cel noise’ to the VRayAdvancedMaterial’s diffuse channel, created a couple of layers with some noise variation and have used VRayDirt (page 43) See file displacement_example .c4d

figure 4.40

Use Cubic projection (for both)

Check Mix textures

Select VrayDisplacement material.

The Displacement type: 2D Mapping, is used when an image based displacement map is available. With this workflow, you can maintain a low polygon count and depend on the displacement map to give the appearance of millions of polygons at a sub polygon level.

In examples figure 4.31 - figure 4.32 the rendered results shows that although the original model only had 68,000 polygons, they’ve been effectively turned to 3.4 million poly-gons with a displacement map.

figure 4.31 ‘Octopus’

Parameters.

The amount value (in both the 3D and 2D options) control the maximum height of the displace-ment map. The shift value specifies a constant amount that the polygons will be shifted relative to their normal position.

While Use default parameters is checked, the resolution for 3D displacement is controlled via the VRayBridge settings under Displace-ment.

The default amount can be set too high for certain tasks and should be experimented with for optimal results.

For more in depth features relating to your displacement needs, please refer to the VRay manual. Note: It’s still possible to add a VRayDisplace-ment Tag from the object manager, although this is the old workflow and only remains available for Legacy reasons (to support older files).

figure 4.42 (zoomed in)

figure 4.43 (zoomed in)

figure 4.33 -is the 16 bit tif image used to create the displacement.

Page 54 Page 55

Luminosity Layer ‘VrayAdvancedMaterial’

The Luminosity layer (from the standard VRayAdvancedMaterial) provides light via self illumination.

You can use self-illuminated materials on objects to represent lights that don’t need an actual light source. An example would be the LCD display on the front of a DVD player, or the backlight for a PDA device.

In VRay, the Luminosity layer also has an option to turn the effect from a standard self illuminated mate-rial into a full fledged light source via the Direct Illumination option. Let’s take a look.

Open example file self_illumination.c4d

The render figure 4.44 has 2 self illuminated objects and a white Environment light. Using the luminosity layer in this manner does not provide adequate shadow density to be considered a viable lighting solution.

figure 4.44 (8 second render)

If you add a Physical Camera tag to the avail-able camera, there’s a drastic dip in exposure. figure 4.45

figure 4.45

To make the luminosity brightness adapt to the physical values of the camera check Compensate exposure. figure 4.46 Note: This is easier than guessing a new intensity amount each time we make a change in exposure via the Physical camera parameters.

figure 4.46Check the box Direct Illumination. This turns the material from a self illumi-nated source to a physical light source.

Enter an Intensity value of 200 for Direct Il-lumination parameters. Also in the Environment tag from the Vray-bridge settings, increase the Background En-vironment brightness to 50 to compensate.

figure 4.47 (Zoomed in)

An increase in Subdivision amount from the Direct illumination parameters can eliminate any unwanted noise. This process is sending samples to the DMC sampler as discussed on page 32. The Direct illumination method is sending out light from all of its surface normals and can be quite slow to compute, however to speed things up it’s possible to check Store with irradiance map and have the light source compute during the IR Map cache process.

Using this approach requires a slightly longer waiting time during IR map creation, but shorter overall render time. It also comes at a cost of a slightly decreased shadow density.

When the Direct illumination option is checked the material now features light-ing properties almost identical to those of a VRay Area light. The Luminosity color channel and texture map slots remain effective for colorization of the light source, but the other channels such a diffuse and specular would be no longer available.

The result of the render should now look like it does in figure 4.48

figure 4.48 (40 second render)

figure 4.49 (22 second render)

Direct illumination does not work with selec-tion tags, instead the system will manually override and use standard self illumination properties. In the case of a single object with geometry you wish to use for light (i.e a lamp and bulb as one object), it is necessary to double click the selection tag (or manually select the polygons) and separate the geometry via the split com-mand. Cinema 4D lacks a split and delete function, so you would also be required to remove the remaining geometry from the original object.

This Direct illumination method can be highly beneficial to your workflow, but it is my recommendation to use it sparingly and only in situations where a physical light source cannot accomplish the same task.

In figure 4.49 the IR Map was responsible for the light source. A full render reveals a slightly softer result when compared to the more grainy direct sampling method.

Page 54 Page 55

Luminosity Layer ‘VrayAdvancedMaterial’

The Luminosity layer (from the standard VRayAdvancedMaterial) provides light via self illumination.

You can use self-illuminated materials on objects to represent lights that don’t need an actual light source. An example would be the LCD display on the front of a DVD player, or the backlight for a PDA device.

In VRay, the Luminosity layer also has an option to turn the effect from a standard self illuminated mate-rial into a full fledged light source via the Direct Illumination option. Let’s take a look.

Open example file self_illumination.c4d

The render figure 4.44 has 2 self illuminated objects and a white Environment light. Using the luminosity layer in this manner does not provide adequate shadow density to be considered a viable lighting solution.

figure 4.44 (8 second render)

If you add a Physical Camera tag to the avail-able camera, there’s a drastic dip in exposure. figure 4.45

figure 4.45

To make the luminosity brightness adapt to the physical values of the camera check Compensate exposure. figure 4.46 Note: This is easier than guessing a new intensity amount each time we make a change in exposure via the Physical camera parameters.

figure 4.46Check the box Direct Illumination. This turns the material from a self illumi-nated source to a physical light source.

Enter an Intensity value of 200 for Direct Il-lumination parameters. Also in the Environment tag from the Vray-bridge settings, increase the Background En-vironment brightness to 50 to compensate.

figure 4.47 (Zoomed in)

An increase in Subdivision amount from the Direct illumination parameters can eliminate any unwanted noise. This process is sending samples to the DMC sampler as discussed on page 32. The Direct illumination method is sending out light from all of its surface normals and can be quite slow to compute, however to speed things up it’s possible to check Store with irradiance map and have the light source compute during the IR Map cache process.

Using this approach requires a slightly longer waiting time during IR map creation, but shorter overall render time. It also comes at a cost of a slightly decreased shadow density.

When the Direct illumination option is checked the material now features light-ing properties almost identical to those of a VRay Area light. The Luminosity color channel and texture map slots remain effective for colorization of the light source, but the other channels such a diffuse and specular would be no longer available.

The result of the render should now look like it does in figure 4.48

figure 4.48 (40 second render)

figure 4.49 (22 second render)

Direct illumination does not work with selec-tion tags, instead the system will manually override and use standard self illumination properties. In the case of a single object with geometry you wish to use for light (i.e a lamp and bulb as one object), it is necessary to double click the selection tag (or manually select the polygons) and separate the geometry via the split com-mand. Cinema 4D lacks a split and delete function, so you would also be required to remove the remaining geometry from the original object.

This Direct illumination method can be highly beneficial to your workflow, but it is my recommendation to use it sparingly and only in situations where a physical light source cannot accomplish the same task.

In figure 4.49 the IR Map was responsible for the light source. A full render reveals a slightly softer result when compared to the more grainy direct sampling method.

Page 56 Page 57

Chapter 5: Vray lightsVRay lights are dependant on scale, when designing a shot with realism in mind it’s important to respect the process and work roughly at the real world size of the object in question. Does this always involve getting out a calculator and pre-planning? No, but the closer you are, the more likely your lights are to behave as expected. Vray lights also have physical parameters for accurate measurement of light.

Lighting actual scenes isn’t a topic we’ll be discussing at length in this short book, but we’ll cover the ba-sics and get you up and running with a few small example scenes.

A standard C4D light with shadow param-eters enabled will provide VRay with enough information to render with a with the stan-dard Omni light option.

The result is an underwhelming effect that’s typical of Omni lights when compared to the shadow density of an Area light. figure 5.01

figure 5.01 (from example file VrayStudioOmni.c4d )

Adding a VRayLight tag to the pair of lights and turning the default Omni light to Area light, a few tweaks later things are starting to look up. figure 5.02

figure 5.02 (from example file VrayStudioArea.c4d )

figure 5.03 (from example file VrayStudioOmni.c4d )

figure 5.04 (from example file VrayStudioOmni.c4d )

Accomplishing this wasn’t a simple case of turning on Area lights, if you note in figure 5.04 that the Default (image) intensity had to be cranked all the way up to 200.

The reason for this is because we’re still us-ing Cinema 4D’s units, which really don’t represent any real world values. Instead if we switch the Intensity units to Radiance (W/m/m/sr), we get a much more accurate representation of their actual brightness. In this case, the area lights are 100 watts.

Note: Always remember to ‘enable shadows’ when working with VRayLights. (This parameter can be found in the VRay Light - Common tab.)

In the VRay manual...

Quote from “http://vrayc4d.com/manuals/vrayforc4d-manual/common-tab” - VrayC4D Group. All right reserved. (c) 2008-2010

“Radiant power (W) - total emitted visible light power mea-sured in watts. When using this setting, the intensity of the light does not depend on its size. Keep in mind that this is not the same as the electric power consumed by a light bulb for example. A typical 100W light bulb only emits between 2 and 3 watts as visible light.

Radiance (W/m²/sr) - visible light surface power measured in watts per square meter per steradian. When this setting is used, the intensity of the light depends on its size.”

....the units are explained in a common sense way.

In the previous scene, the illumination strength for the light is heavily compensated by the exposure settings of physical camera. Without the physical camera in place, the scene would have been massively overbright.

In example file watt_the_hell.c4d I have a very small area light in close proximity to the sphere with the physical camera tag re-moved. I’ve done this to view the lights in their ‘raw’ default intensity state.

This small area light has a Radiance (W/m²/sr) value of 20 and a Radiant power (W) value of 5.97.

figure 5.05 (from example file watt_the_hell.c4d )

Increasing the size of the light figure 5.06, the Radiance (W/m²/sr) value remains at 20 but the Radiant power (W) value has now increased to 41.7

Notice also that with the size change comes a dramatic shift in shadow density. This is a real world phenomenon of course and quite easy to understand why this would happen. Larger area lights typically require more samples to render accurately.

figure 5.06 (from example file watt_the_hell.c4d )

figure 5.07

figure 5.08

In figure 5.08 I’ve changed the Area type to Sphere. We’ll want to scale this down to rep-resent a bulb.

Page 56 Page 57

Chapter 5: Vray lightsVRay lights are dependant on scale, when designing a shot with realism in mind it’s important to respect the process and work roughly at the real world size of the object in question. Does this always involve getting out a calculator and pre-planning? No, but the closer you are, the more likely your lights are to behave as expected. Vray lights also have physical parameters for accurate measurement of light.

Lighting actual scenes isn’t a topic we’ll be discussing at length in this short book, but we’ll cover the ba-sics and get you up and running with a few small example scenes.

A standard C4D light with shadow param-eters enabled will provide VRay with enough information to render with a with the stan-dard Omni light option.

The result is an underwhelming effect that’s typical of Omni lights when compared to the shadow density of an Area light. figure 5.01

figure 5.01 (from example file VrayStudioOmni.c4d )

Adding a VRayLight tag to the pair of lights and turning the default Omni light to Area light, a few tweaks later things are starting to look up. figure 5.02

figure 5.02 (from example file VrayStudioArea.c4d )

figure 5.03 (from example file VrayStudioOmni.c4d )

figure 5.04 (from example file VrayStudioOmni.c4d )

Accomplishing this wasn’t a simple case of turning on Area lights, if you note in figure 5.04 that the Default (image) intensity had to be cranked all the way up to 200.

The reason for this is because we’re still us-ing Cinema 4D’s units, which really don’t represent any real world values. Instead if we switch the Intensity units to Radiance (W/m/m/sr), we get a much more accurate representation of their actual brightness. In this case, the area lights are 100 watts.

Note: Always remember to ‘enable shadows’ when working with VRayLights. (This parameter can be found in the VRay Light - Common tab.)

In the VRay manual...

Quote from “http://vrayc4d.com/manuals/vrayforc4d-manual/common-tab” - VrayC4D Group. All right reserved. (c) 2008-2010

“Radiant power (W) - total emitted visible light power mea-sured in watts. When using this setting, the intensity of the light does not depend on its size. Keep in mind that this is not the same as the electric power consumed by a light bulb for example. A typical 100W light bulb only emits between 2 and 3 watts as visible light.

Radiance (W/m²/sr) - visible light surface power measured in watts per square meter per steradian. When this setting is used, the intensity of the light depends on its size.”

....the units are explained in a common sense way.

In the previous scene, the illumination strength for the light is heavily compensated by the exposure settings of physical camera. Without the physical camera in place, the scene would have been massively overbright.

In example file watt_the_hell.c4d I have a very small area light in close proximity to the sphere with the physical camera tag re-moved. I’ve done this to view the lights in their ‘raw’ default intensity state.

This small area light has a Radiance (W/m²/sr) value of 20 and a Radiant power (W) value of 5.97.

figure 5.05 (from example file watt_the_hell.c4d )

Increasing the size of the light figure 5.06, the Radiance (W/m²/sr) value remains at 20 but the Radiant power (W) value has now increased to 41.7

Notice also that with the size change comes a dramatic shift in shadow density. This is a real world phenomenon of course and quite easy to understand why this would happen. Larger area lights typically require more samples to render accurately.

figure 5.06 (from example file watt_the_hell.c4d )

figure 5.07

figure 5.08

In figure 5.08 I’ve changed the Area type to Sphere. We’ll want to scale this down to rep-resent a bulb.

Page 58 Page 59

As I decrease the Spherical Area light radius to approximately 5cm, you’ll notice that the editor view becomes distracting and overbright. This is a common nuisance that requires only a simple logical understanding to remedy.

figure 5.09

figure 5.10

VRay lights don’t have falloff parameters as they do in Cinema 4D. They’re physi-cal based and won’t respond to falloff size change. So to remedy this overbright state simply manually drag the larger spheres handles and close them down to approxi-mately the size of your light radius.

With this you’re controlling the falloff dis-tance and editor visibility/brightness of said light and not anything related to the actual render. You can manually do this in the standard C4D light setting by clicking the light and not the VRayLight tag. figure 5.11

figure 5.11

figure 5.11 (from example file a_bulb_of_sorts.c4d )

Another quick render figure 5.11, Radiance (W/m²/sr) value of 401 and a Radiant power (W) value of 41 So you get the picture.

Personally I stick with the native Cinema 4D units for lighting, they don’t represent any-thing but I’m comfortable with that work-flow. It’s not imperative to learn about watt-age and luminous power etc, unless you’re in a position to light based on pre-existing data. It’s all about personal preference.

figure 5.12 Is one better than the other?

The choice to use Rectangular lights vs Spherical figure 5.12 one is a question of “what’s right for the job” - They have uniquely differ-ent ways of casting shadows/light and should represent the kind of light you’re looking to cast into the scene. Though I find the spherical light to be highly versatile in a lot of cases, the rectangular shape is good for a whole range of lighting situations.

Area Light - Light portalsWe’ve taken a quick look at Area light settings, now we’ll dig a little deeper

figure 5.13

In figure 5.13 we have a typical Sun/Sky setup with a very small opening. This is allowing a little light to enter the room, but not enough samples are reaching the interior for a qual-ity result. The first idea would be to totally max out the IR map, DMC sampler settings etc, but there’s a simpler way to approach this with a Light Portal.

Open scene Small_Hole.c4d and if you’d like to render to the picture render for comparison.

First thing to notice in the scene is an Area Light that has been turned off. Opening the light parameters via the Vray light tag reveals what looks to be only a standard area light, however the property ‘Light portal’ has been switched from Normal to Portal Light.

Checking the light to on in the OM and re-rendering will now show a much clearer and less splotchy render. figure 5.14

figure 5.14

The light portal setting has effectively turned this light source into a sort of directional guide for the samples.

In my crap illustration below figure 5.15 you can see that without the Light Portal, the red samples miss the mark and don’t make it into the scene. With the Light Portal activated, the samples have assistance in their intended direction .

figure 5.15

The other solution is the Simple Light Portal which ignores any lights/objects behind the portal and takes only the environment color into consideration. This can speed up the workflow slightly. Light Portals can be helpful but are rarely used in latest versions of Vray as the GI algo-rithm has become more refined. Though in situations like this, they can be used to your advantage.

Page 58 Page 59

As I decrease the Spherical Area light radius to approximately 5cm, you’ll notice that the editor view becomes distracting and overbright. This is a common nuisance that requires only a simple logical understanding to remedy.

figure 5.09

figure 5.10

VRay lights don’t have falloff parameters as they do in Cinema 4D. They’re physi-cal based and won’t respond to falloff size change. So to remedy this overbright state simply manually drag the larger spheres handles and close them down to approxi-mately the size of your light radius.

With this you’re controlling the falloff dis-tance and editor visibility/brightness of said light and not anything related to the actual render. You can manually do this in the standard C4D light setting by clicking the light and not the VRayLight tag. figure 5.11

figure 5.11

figure 5.11 (from example file a_bulb_of_sorts.c4d )

Another quick render figure 5.11, Radiance (W/m²/sr) value of 401 and a Radiant power (W) value of 41 So you get the picture.

Personally I stick with the native Cinema 4D units for lighting, they don’t represent any-thing but I’m comfortable with that work-flow. It’s not imperative to learn about watt-age and luminous power etc, unless you’re in a position to light based on pre-existing data. It’s all about personal preference.

figure 5.12 Is one better than the other?

The choice to use Rectangular lights vs Spherical figure 5.12 one is a question of “what’s right for the job” - They have uniquely differ-ent ways of casting shadows/light and should represent the kind of light you’re looking to cast into the scene. Though I find the spherical light to be highly versatile in a lot of cases, the rectangular shape is good for a whole range of lighting situations.

Area Light - Light portalsWe’ve taken a quick look at Area light settings, now we’ll dig a little deeper

figure 5.13

In figure 5.13 we have a typical Sun/Sky setup with a very small opening. This is allowing a little light to enter the room, but not enough samples are reaching the interior for a qual-ity result. The first idea would be to totally max out the IR map, DMC sampler settings etc, but there’s a simpler way to approach this with a Light Portal.

Open scene Small_Hole.c4d and if you’d like to render to the picture render for comparison.

First thing to notice in the scene is an Area Light that has been turned off. Opening the light parameters via the Vray light tag reveals what looks to be only a standard area light, however the property ‘Light portal’ has been switched from Normal to Portal Light.

Checking the light to on in the OM and re-rendering will now show a much clearer and less splotchy render. figure 5.14

figure 5.14

The light portal setting has effectively turned this light source into a sort of directional guide for the samples.

In my crap illustration below figure 5.15 you can see that without the Light Portal, the red samples miss the mark and don’t make it into the scene. With the Light Portal activated, the samples have assistance in their intended direction .

figure 5.15

The other solution is the Simple Light Portal which ignores any lights/objects behind the portal and takes only the environment color into consideration. This can speed up the workflow slightly. Light Portals can be helpful but are rarely used in latest versions of Vray as the GI algo-rithm has become more refined. Though in situations like this, they can be used to your advantage.

Page 60 Page 61

Area Light - DomeThe Area light type - Dome is a similar to using a color or hdr effect as the Environment background color, but uses direct sampling to provide a much more accurate result.

figure 5.16 (Environment from VRay Settings)

figure 5.17 (Environment slot VRay Settings)

In figures 5.16 & 5.17 I’ve loaded a *.hdr image into the texture slot of the Environment background and have a standard GI setup ready to render.

The resulting render figure 5.18 has been processed much like a standard luminance material. Light is being cast into the scene but the sampling method is not direct.

While this is suitable for most tasks (espe-cially with an accompanying light setup), if you want some extra bang for your buck, the Area light Dome is more powerful.

figure 5.18

figure 5.19

figure 5.16 (Environment tab from VRay Settings)

figure 5.20

Controlling this light source is straight for-ward. Position of the light in your scene is irrelevant, however rotation values will affect the orientation of an image based map. A color/texture/material effect is loaded into the slot (in this case ennis.hdr) and the result figure 5.20 is a directly sampled dome light.

Samples can be adjusted according.

Area Light - MeshUsing a Mesh as a light source is one way to cast light from geometry. Though this effect does not differ and is easier to setup using Direct Illumination in a luminance channel.

figure 5.21

In the simple scene Vray_Mesh.c4d the light on the upper left figure 5.21 is utilizing the Vray Light type - Mesh and has the cube object loaded into the empty geometry slot figure 5.22

figure 5.22

The object on the right has a VRay material with a Luminance material applied and the direct illumination option switched on.

figure 5.23

As you can see figure 5.23 there’s no difference the two workflows, other than ease of setup.

A practical usage of this method is to cre-ate customized light shapes such as a curved plane or to match the shape and size of a pre-existing light fixture. Though I wouldn’t recommend lighting exclusively with this technique in mind, it can be perfect to add the finishing touches to an interior scene.

Prior to the creation of the Direct illumina-tion method in the luminance channel, it was not possible to pick and chose work flows. In the scene from figure 5.24 Mesh lights were used throughout the piece to light areas that needed to match the shape of the open-ing.

figure 5.24 “Inspire city”

Page 60 Page 61

Area Light - DomeThe Area light type - Dome is a similar to using a color or hdr effect as the Environment background color, but uses direct sampling to provide a much more accurate result.

figure 5.16 (Environment from VRay Settings)

figure 5.17 (Environment slot VRay Settings)

In figures 5.16 & 5.17 I’ve loaded a *.hdr image into the texture slot of the Environment background and have a standard GI setup ready to render.

The resulting render figure 5.18 has been processed much like a standard luminance material. Light is being cast into the scene but the sampling method is not direct.

While this is suitable for most tasks (espe-cially with an accompanying light setup), if you want some extra bang for your buck, the Area light Dome is more powerful.

figure 5.18

figure 5.19

figure 5.16 (Environment tab from VRay Settings)

figure 5.20

Controlling this light source is straight for-ward. Position of the light in your scene is irrelevant, however rotation values will affect the orientation of an image based map. A color/texture/material effect is loaded into the slot (in this case ennis.hdr) and the result figure 5.20 is a directly sampled dome light.

Samples can be adjusted according.

Area Light - MeshUsing a Mesh as a light source is one way to cast light from geometry. Though this effect does not differ and is easier to setup using Direct Illumination in a luminance channel.

figure 5.21

In the simple scene Vray_Mesh.c4d the light on the upper left figure 5.21 is utilizing the Vray Light type - Mesh and has the cube object loaded into the empty geometry slot figure 5.22

figure 5.22

The object on the right has a VRay material with a Luminance material applied and the direct illumination option switched on.

figure 5.23

As you can see figure 5.23 there’s no difference the two workflows, other than ease of setup.

A practical usage of this method is to cre-ate customized light shapes such as a curved plane or to match the shape and size of a pre-existing light fixture. Though I wouldn’t recommend lighting exclusively with this technique in mind, it can be perfect to add the finishing touches to an interior scene.

Prior to the creation of the Direct illumina-tion method in the luminance channel, it was not possible to pick and chose work flows. In the scene from figure 5.24 Mesh lights were used throughout the piece to light areas that needed to match the shape of the open-ing.

figure 5.24 “Inspire city”

Page 62 Page 63

Area Light - Remaining settingsWe’ll take a brief at the remaining settings from the Area light tab.

Affect Reflections: With this option unchecked, the brightness of the light will be ignored by the material reflectivity.

Invisible: All light sources are visible unless otherwise indicated. Unchecking this option will provide a light source, thought the origin of the light will not be visible.

No Decay: All lights in VRay have decay (falloff) based on real world calculations. Enabling No Decay will essentially create a light source with no falloff at all. This is not recommended when trying to realisti-cally light a scene, but can be useful in product shots if you require an infinite light source. Double sided: A rectangular area light emits light from the Z+ direction only, enabling Double Sided enables the light to illuminate from both surface normals. *CHECK

Samples: As discussed on Page 32, the amount of samples used determines the quality of the light source. Lights producing undesirable noise benefit from additional samples.

Store with Irradiance map Using this option, the light calculated from the Area map is processed and stored during the Irradiance map calculation. Discussed on Page 55.

IES lights IES data is taken from existing real world lighting fixtures and is made available for users in varying professions to download and utilize in their projects.

figure 5.25

An IES represents the shape of the lights fall-off, but not the falloff amount. In figure 5.25 it’s easy to recognize the differences in how each light reacts to the IES data.

Open example file IES_scene.c4d

The first thing you’ll notice in this scene if using Cinema 4D version 12 or higher, is that the visual reference of the IES light is incorrectly oriented figure 5.26.

figure 5.26

This is the standard rotational value of the default light. To fix it, rotate the p axis (the blue handle) to -90°. Note: Targets will always utilize the P axis.

Omni is the light type indicated to use when working with IES files. Creating a standard light and enabling shadows, you can then quickly move over the IES tab and load your desired IES file.Open example file IES_scene2.c4d

figure 5.27In this scene figure 5.27 the light is unchanged and retains the default brightness as con-tained in the IES data. To increase brightness you can enter a Lumens value for an increase in intensity, this value would typically be quite high. I’m going to increase to 10,000. Enabling Soft shadows does as you would ex-pect, it softens the shadow density, which is occasionally desirable and only slightly more time consuming to render. A hint of color in the filter color will tint the IES light to the desired value. Rarely are lights 100% white, making a tint a worth-while change. figure 5.28

figure 5.28

Page 62 Page 63

Area Light - Remaining settingsWe’ll take a brief at the remaining settings from the Area light tab.

Affect Reflections: With this option unchecked, the brightness of the light will be ignored by the material reflectivity.

Invisible: All light sources are visible unless otherwise indicated. Unchecking this option will provide a light source, thought the origin of the light will not be visible.

No Decay: All lights in VRay have decay (falloff) based on real world calculations. Enabling No Decay will essentially create a light source with no falloff at all. This is not recommended when trying to realisti-cally light a scene, but can be useful in product shots if you require an infinite light source. Double sided: A rectangular area light emits light from the Z+ direction only, enabling Double Sided enables the light to illuminate from both surface normals. *CHECK

Samples: As discussed on Page 32, the amount of samples used determines the quality of the light source. Lights producing undesirable noise benefit from additional samples.

Store with Irradiance map Using this option, the light calculated from the Area map is processed and stored during the Irradiance map calculation. Discussed on Page 55.

IES lights IES data is taken from existing real world lighting fixtures and is made available for users in varying professions to download and utilize in their projects.

figure 5.25

An IES represents the shape of the lights fall-off, but not the falloff amount. In figure 5.25 it’s easy to recognize the differences in how each light reacts to the IES data.

Open example file IES_scene.c4d

The first thing you’ll notice in this scene if using Cinema 4D version 12 or higher, is that the visual reference of the IES light is incorrectly oriented figure 5.26.

figure 5.26

This is the standard rotational value of the default light. To fix it, rotate the p axis (the blue handle) to -90°. Note: Targets will always utilize the P axis.

Omni is the light type indicated to use when working with IES files. Creating a standard light and enabling shadows, you can then quickly move over the IES tab and load your desired IES file.Open example file IES_scene2.c4d

figure 5.27In this scene figure 5.27 the light is unchanged and retains the default brightness as con-tained in the IES data. To increase brightness you can enter a Lumens value for an increase in intensity, this value would typically be quite high. I’m going to increase to 10,000. Enabling Soft shadows does as you would ex-pect, it softens the shadow density, which is occasionally desirable and only slightly more time consuming to render. A hint of color in the filter color will tint the IES light to the desired value. Rarely are lights 100% white, making a tint a worth-while change. figure 5.28

figure 5.28

Page 64 Page 65

Final notes on lightingThe remaining light sources are Spot, Infinite and Parallel. I won’t cover these in detail because their pa-rameters are logical and require no special attention.

In future PDF instructional manuals we’ll take a closer look at lighting individual scenes.

Lighting in VRay is a unique process, one that can be as simple as the Physical Sun/Sky setup or as com-plex as lighting a city. My advice is to stay away from the simplest work flow and push the boundaries of what can be done with lighting and composition. Before tackling a project that involves a lighting rig, try to think of the balance you want to strike before-hand. In a night time shot for example - Would it be wise to create the overall environment light first, fills etc and then work your way down to the lighting fixtures? I would say not. My approach is to always start small, lighting fixtures first, achieve a sense of balance with the smaller details and when you’ve refined and refined some more, only then would it be time to look towards the bigger lights. Lighting can be a tedious part of the process if you make it so, continuously rendering the same shot time and time again. This is why I recommend a base test setting, where the results of your scene lights can be visualized in a matter of seconds vs waiting 10 minutes every time you make a change. Get used to switching out between crap settings and medium ones to ensure you get overall sense for your scene and to ensure that with better settings, the lights will withstand scrutiny. When you arrive to a point where the correct values flow, lighting is perhaps the most interesting part of the project, after all this process is what brings your work to life. It makes or breaks your work, so pay careful attention to what the masters do and try to replicate the best rigs without settling for mediocrity.

Chapter 6: Environment FogPrior to there being a working fog solution in VRay, there were definite limitations when using the render engine for environment design and landscapes. Eventually ChaosGroup introduced the Environment fog, which is a unique and physically accurate calculation of scene fog. The concept may seem quite limiting, “how often do I want fog?” Yet the implementation opens up a world of creativity. Let’s first take a quick look at what it can do in terms of finished projects.

figure 6.1 ‘Sunday’ figure 6.2 ‘Fall’ figure 6.3 Modern fog test

The scene ‘Sunday’ figure 6.1 is initially setup with only a physical sun/sky, but due to the Environment fog and the enabled Scatter GI parameter, the sun light is able to illuminate the fog. The result as in real life is that the fog itself becomes a source of illumination for the scene and the actual sun light and it’s potential shadow casting has diminished to such a degree that it’s almost completely invisible. An increase in expo-sure and an adequate interior lighting rig restores the balance. The scene ‘Fall’ figure 6.2 is setup with Proxy objects and consists of around 2 billion polygons. Fog with GI scattering is enabled and is indicated to reach a height of 4 meters at a distance of 50 meters. This clears the way for sun to still have a visible affect on the scene, but creates a sense of depth that would otherwise not be possible.

The scene ‘Modern fog test’ figure 6.3 was the first real test where I used the Environment fog parameters. Given my lack of understanding at the time it’s easy to for me to critique the work. The fog height is es-sentially infinite, which under such heavy fog cover doesn’t allow any light penetration from the Sun. Given an opportunity to re-work this piece, I would have chosen more fitting parameters.

So let’s do that, let’s figure out what works best by creating a fog lit scene.

Page 64 Page 65

Final notes on lightingThe remaining light sources are Spot, Infinite and Parallel. I won’t cover these in detail because their pa-rameters are logical and require no special attention.

In future PDF instructional manuals we’ll take a closer look at lighting individual scenes.

Lighting in VRay is a unique process, one that can be as simple as the Physical Sun/Sky setup or as com-plex as lighting a city. My advice is to stay away from the simplest work flow and push the boundaries of what can be done with lighting and composition. Before tackling a project that involves a lighting rig, try to think of the balance you want to strike before-hand. In a night time shot for example - Would it be wise to create the overall environment light first, fills etc and then work your way down to the lighting fixtures? I would say not. My approach is to always start small, lighting fixtures first, achieve a sense of balance with the smaller details and when you’ve refined and refined some more, only then would it be time to look towards the bigger lights. Lighting can be a tedious part of the process if you make it so, continuously rendering the same shot time and time again. This is why I recommend a base test setting, where the results of your scene lights can be visualized in a matter of seconds vs waiting 10 minutes every time you make a change. Get used to switching out between crap settings and medium ones to ensure you get overall sense for your scene and to ensure that with better settings, the lights will withstand scrutiny. When you arrive to a point where the correct values flow, lighting is perhaps the most interesting part of the project, after all this process is what brings your work to life. It makes or breaks your work, so pay careful attention to what the masters do and try to replicate the best rigs without settling for mediocrity.

Chapter 6: Environment FogPrior to there being a working fog solution in VRay, there were definite limitations when using the render engine for environment design and landscapes. Eventually ChaosGroup introduced the Environment fog, which is a unique and physically accurate calculation of scene fog. The concept may seem quite limiting, “how often do I want fog?” Yet the implementation opens up a world of creativity. Let’s first take a quick look at what it can do in terms of finished projects.

figure 6.1 ‘Sunday’ figure 6.2 ‘Fall’ figure 6.3 Modern fog test

The scene ‘Sunday’ figure 6.1 is initially setup with only a physical sun/sky, but due to the Environment fog and the enabled Scatter GI parameter, the sun light is able to illuminate the fog. The result as in real life is that the fog itself becomes a source of illumination for the scene and the actual sun light and it’s potential shadow casting has diminished to such a degree that it’s almost completely invisible. An increase in expo-sure and an adequate interior lighting rig restores the balance. The scene ‘Fall’ figure 6.2 is setup with Proxy objects and consists of around 2 billion polygons. Fog with GI scattering is enabled and is indicated to reach a height of 4 meters at a distance of 50 meters. This clears the way for sun to still have a visible affect on the scene, but creates a sense of depth that would otherwise not be possible.

The scene ‘Modern fog test’ figure 6.3 was the first real test where I used the Environment fog parameters. Given my lack of understanding at the time it’s easy to for me to critique the work. The fog height is es-sentially infinite, which under such heavy fog cover doesn’t allow any light penetration from the Sun. Given an opportunity to re-work this piece, I would have chosen more fitting parameters.

So let’s do that, let’s figure out what works best by creating a fog lit scene.

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figure 6.4

Open example file Home_fog.c4dHere figure 6.4 we have another typical Sun/Sky setup, pretty standard scene. We’re going to spice things up with a little fog.

First, let’s go to the editor camera and create a primitive cube figure 6.5.

figure 6.5

Manipulate the cube to extend the outside of the building, without penetrating the the window & building layer figure 6.6. We’re keep-ing the fog strictly outside.

figure 6.5 - Cube has Xray effect for illustration only.

In the VRay settings rollout for Environmentwe’re going to activate Environment Fog.

figure 6.6

If you’d like to run a test render, you’ll see the results are almost completely black. Add the Cube object to the open slot for Gizmos and add the Sun object to the open slot for Lights. Another render reveals a shot almost identi-cal to the original, minus the slightest hint of haze figure 6.7.

figure 6.7

We’ll want to check the Scatter GI box.

This tells VRay to look at the Fog as a vol-ume and calculate its light solution based on the density of that matter. The scattering will both illuminate the fog and determine how much light can escape the solution.

Another render would still resemble that of the original.

To finally see a result of using the Environ-ment Fog, we’ll want to manipulate the Fog Distance parameter, bringing that numerical value down from 1000 to around 100.

The change in distance affects the density, visible fog at closer proximity is now thicker, allowing less light to penetrate. Your result may look slightly different than mine figure 6.8 based on the exact shape of your Gizmo geometry.

figure 6.8

The Gizmo object (setting geometry as the fog) is the preferred workflow as this gives us more control over the density of the fog. Without a gizmo we’re using infinite fog depth and using the Fog height parameter which can be more difficult to control. Sunlight is still able to penetrate the scene, but has become obscured by the fog element. Subtle compensation with exposure or an interior lighting rig would be the next step.

It’s possible to use any shapes as a Gizmo object no matter how irregular, allowing you to experiment with just about any geometry imaginable. It’s also possible to use as many light as required in order to scatter light through the fog density.

In figure 6.9 I’ve added two makeshift security lights outside the building and included those additions in the Environment fog Light slot.

figure 6.9

You can see that this simple addition had added to the fog illumination, which in turn casts more unique light into the scene. A couple of interior lights to compliment the outside, a little furniture, materiality and you have an interesting setup. Certainly some-thing outside of the boring Physical sky look.

figure 6.10By adding some outside features, you’ll give life and more depth to the exterior. In figure 6.11 the eye is drawn to the passers by, which creates more interest.

figure 6.11

Page 66 Page 67

figure 6.4

Open example file Home_fog.c4dHere figure 6.4 we have another typical Sun/Sky setup, pretty standard scene. We’re going to spice things up with a little fog.

First, let’s go to the editor camera and create a primitive cube figure 6.5.

figure 6.5

Manipulate the cube to extend the outside of the building, without penetrating the the window & building layer figure 6.6. We’re keep-ing the fog strictly outside.

figure 6.5 - Cube has Xray effect for illustration only.

In the VRay settings rollout for Environmentwe’re going to activate Environment Fog.

figure 6.6

If you’d like to run a test render, you’ll see the results are almost completely black. Add the Cube object to the open slot for Gizmos and add the Sun object to the open slot for Lights. Another render reveals a shot almost identi-cal to the original, minus the slightest hint of haze figure 6.7.

figure 6.7

We’ll want to check the Scatter GI box.

This tells VRay to look at the Fog as a vol-ume and calculate its light solution based on the density of that matter. The scattering will both illuminate the fog and determine how much light can escape the solution.

Another render would still resemble that of the original.

To finally see a result of using the Environ-ment Fog, we’ll want to manipulate the Fog Distance parameter, bringing that numerical value down from 1000 to around 100.

The change in distance affects the density, visible fog at closer proximity is now thicker, allowing less light to penetrate. Your result may look slightly different than mine figure 6.8 based on the exact shape of your Gizmo geometry.

figure 6.8

The Gizmo object (setting geometry as the fog) is the preferred workflow as this gives us more control over the density of the fog. Without a gizmo we’re using infinite fog depth and using the Fog height parameter which can be more difficult to control. Sunlight is still able to penetrate the scene, but has become obscured by the fog element. Subtle compensation with exposure or an interior lighting rig would be the next step.

It’s possible to use any shapes as a Gizmo object no matter how irregular, allowing you to experiment with just about any geometry imaginable. It’s also possible to use as many light as required in order to scatter light through the fog density.

In figure 6.9 I’ve added two makeshift security lights outside the building and included those additions in the Environment fog Light slot.

figure 6.9

You can see that this simple addition had added to the fog illumination, which in turn casts more unique light into the scene. A couple of interior lights to compliment the outside, a little furniture, materiality and you have an interesting setup. Certainly some-thing outside of the boring Physical sky look.

figure 6.10By adding some outside features, you’ll give life and more depth to the exterior. In figure 6.11 the eye is drawn to the passers by, which creates more interest.

figure 6.11

Page 68 Page 69

That’s a wrapI hope your experiences with this booklet have been positive.

If you have any additional question for clarification please contact me at

thec4dvault@hotmail.com

Join me again in the near future.

LinksI’d have spent some time teaching VRay for animation, but upon review there is little more I can say than what has already been clearly spelled out on the VRay message board by ‘STRAT’

These step by step guides will get you through both ‘GI object animation’ and ‘GI camera animation’Though if you have any remaining questions, please feel free to email me @ thec4dvault@hotmail.com

http://forum.vrayforc4d.com/showthread.php?t=7727&highlight=object+animationhttp://forum.vrayforc4d.com/showthread.php?t=7728

Even with knowledge of VRayForC4D, I still refer to these tutorials as a step by step checklist.

For Clarification and further reading on any of the subjects covered here, the VRay manual is an excellent resources with up to date information.

http://vrayc4d.com/manuals/booktree

Here’s a couple of older tutorials I created with regard to illumination skyscarpes. You may or may not find these useful.

http://vrayc4d.com/manuals/vrayc4d-tutorials/skyscraper-lighting-inthecityhttp://vrayc4d.com/manuals/vrayc4d-tutorials/city-illumination-inthecity

For Free models

http://archive3d.net/

And the best collection of textures available online

http://www.cgtextures.com/

And finally - Exclusively VRay based materials

http://www.vrayforc4d.com/portal/materials/

Page 68 Page 69

That’s a wrapI hope your experiences with this booklet have been positive.

If you have any additional question for clarification please contact me at

thec4dvault@hotmail.com

Join me again in the near future.

LinksI’d have spent some time teaching VRay for animation, but upon review there is little more I can say than what has already been clearly spelled out on the VRay message board by ‘STRAT’

These step by step guides will get you through both ‘GI object animation’ and ‘GI camera animation’Though if you have any remaining questions, please feel free to email me @ thec4dvault@hotmail.com

http://forum.vrayforc4d.com/showthread.php?t=7727&highlight=object+animationhttp://forum.vrayforc4d.com/showthread.php?t=7728

Even with knowledge of VRayForC4D, I still refer to these tutorials as a step by step checklist.

For Clarification and further reading on any of the subjects covered here, the VRay manual is an excellent resources with up to date information.

http://vrayc4d.com/manuals/booktree

Here’s a couple of older tutorials I created with regard to illumination skyscarpes. You may or may not find these useful.

http://vrayc4d.com/manuals/vrayc4d-tutorials/skyscraper-lighting-inthecityhttp://vrayc4d.com/manuals/vrayc4d-tutorials/city-illumination-inthecity

For Free models

http://archive3d.net/

And the best collection of textures available online

http://www.cgtextures.com/

And finally - Exclusively VRay based materials

http://www.vrayforc4d.com/portal/materials/