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Geometry To Maya Hair 2 Quick Start Guide

BY PHUNG DINH DZUNG

GMH 2 GMH Hair Style

Rendering Tutorial

1 CONTENT

2 Overview............................................................................................................................................................................................................................ 2

3 Edit Hair Width and Hairs Per Clump ............................................................................................................................................................................. 2

4 Edit Hair Width Scale. ....................................................................................................................................................................................................... 3

5 Edit Sub Clumping , Noise & Rand Value ..................................................................................................................................................................... 3

6 Edit Hair Shader ................................................................................................................................................................................................................ 4

7 Adding secondary Style System:.................................................................................................................................................................................... 5

8 Apply Vray Material to GMH2 Hair Style System.......................................................................................................................................................... 8

9 Working with Dynamic: .................................................................................................................................................................................................... 8

10 Other settings .................................................................................................................................................................................................................... 8

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Geometry To Maya Hair 2 Quick Start Guide

BY PHUNG DINH DZUNG

2 Overview

In this tutorial, we will cover workflows to tweak GMH2 Style system settings and render GMH2 Maya hair.

We will be using the popular render engine that come with Maya - Mental Ray, same workflow can be applied to any other engines that

can render Maya Hair.

Before working with GMH Style System or Maya Hair system, if you are not familiar with one of those please take a look at the structures of

how Maya Hair organize its hair system.

3 Edit Hair Width and Hairs Per Clump

Open up the file : GMH2.6_tutorialFile005_lightingSetup.ma . You will have a

completed hair model converted to GMH Surfaces.

There were already some spots lights set up in the scene. Do a test render using

Mental Ray you should get this image.

The width of individual hair strand is too big so we need to reduce the thickness of

hair strand by lowering the value "GMHHair Width" to 0.02

Increase Mental Ray render quality so we can see small hair strand better. Now the

hair strand appear smaller causing the all the hair clumps losing its volume/ thickness.

To reserve hair volume we need to increase number of Hairs Per Clump while

decrease the hair width.

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Geometry To Maya Hair 2 Quick Start Guide

BY PHUNG DINH DZUNG

Increase the hairs per clump to 30 and do a render again, you will see that the Hair model now have its column back with much smoother

look due to smaller hair strands. Increase Hairs Per Clump also make render time longer, so you would need to find a balance ratio

between Hairs Per Clump and Hair Width depend on the scene you are rendering.

Note: there might be a warning " Warning: RedHair_pfxHair was only partially drawn (for hints see doc for Paint Effects:

maxDrawSegments)." because of too many hair strands are being displayed on viewport, this doesnt affect the render result, Maya just

need to hide part of the hair in the viewport to save memory, you can lower Display Quality to view the hair model in fewer strands.

4 Edit Hair Width Scale.

Do a close up render of the hair root. There is a sharp border between hair clumps roots which is very unnatural. This is because while

the hair Clump is smaller at the root , but the hair strand width is the same - mean more density. We can improve this by widen then width

of hair clumps' roots a little while decrease the width of hair strand 's roots.

Initial settings

Widen the hair clumps root width

Then thinning the hair strand root width.

Root of hair clumps will make much softer.

5 Edit Sub Clumping , Noise & Rand Value

Now we have much softer and smooth looking hair model, but it still not good enough because of the uniform perfection of all the hair

strands. We need to put some randomize element into it by adding sub clumping, noise and rand value of hair shader.

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Geometry To Maya Hair 2 Quick Start Guide

BY PHUNG DINH DZUNG

6 Edit Hair Shader

Next step is to tweak the hair shader.

Change the Hair color and specular

Adding random value to Color and specular

The setting in GMH Style System let you change the shader for the all GMH surfaces, but you can also select individual GMH Surface and

assign override hair color via Surface Edit Tab on GMH2 window.

Select GMH Surface to override setting

Apply Override settings to selected

Surfaces in GMH Surface tab

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Geometry To Maya Hair 2 Quick Start Guide

BY PHUNG DINH DZUNG

Open file GMH2.6_tutorialFile006_renderTweak.ma for final hair model.

7 Adding secondary Style System:

Now that you have a good base to edit and adding further detail onto your hair model. Below are some of GMH2 functions to help you

adding details to your hair model

Looking at picture below, we can split the hair style into 3 main types with distinctive characteristics from each other :

- The main Hair Clumps that make up most of the hair volume .

- The second hair clumps that were spitted into smaller clusters/ sub-clump groups that add randomize and natural looking to the hair.

- The third one - the floating small and thin hair strands that floating around the main clump that has lighter color and catch light better

which would make our hair model look much more realistic.

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Geometry To Maya Hair 2 Quick Start Guide

BY PHUNG DINH DZUNG

GMH2 allow us to apply more than one style system of the same kind ( Hair

style system or Poly style system ) onto same GMH Surface.

We will create an additional GMH Hair style system to add

on top of our base "RedHair" style system. Click "Create

GMH Style" to create new hair style system and name it

"RedHair_2nd".

Set the new RedHair_2nd style system as current style system, select one of GMH Surface and click " Apply 2nd GMHStyle" to apply

additional style System on selected GMH Surfaces.

You will see there is a few brow hair strands were added on top of the red hair.

Tweak the "RedHair_2nd" style system to look like "RedHair" style system but with more sub clumping value and bigger clump width to make

it floating ontop of the main style system.

You can save the base "RedHair" syle system as a preset and apply it to the 2nd style to save time .

Setting of the 2nd hair style

Before - after comparison when adding 2nd style system

onto GMH Surface, the hair look more complex and detail.

Select a few important GMH

Surfaces to apply 2nd style

system

Carry on the same workflow for 3rd hair style to add small floating hair strands to the hair model.

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Geometry To Maya Hair 2 Quick Start Guide

BY PHUNG DINH DZUNG

You can find the GMH preset files for 3 of these Style System in tutorial_files folder or open the file

" GMH2.6_tutorialFile007_applySecondaryHairStyle.ma" for final hair style with 3 style systems setup.

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Geometry To Maya Hair 2 Quick Start Guide

BY PHUNG DINH DZUNG

8 Apply Vray Material to GMH2 Hair Style System

Because GMH2 output Maya Hair system so the workflow to apply Vray Material or any other renders are the same when working wi th

traditional Maya Hair System node.

For Vray , Set the GMH Style system as current Style,

click on Edit Maya Hair to select the Maya Hair system

Node under GMH Style System container, in Attribute

editor go to Attribute -> Vray -> Hair Shader

9 Working with Dynamic:

By selecting this Maya Hair System node you can also assign an Nucleus solver to the Maya Hair system node and access to N-cache .

10 Other settings

There are many other attributes to work with hair styling inside GMH

Hair Style System Node, this tutorial will only cover some of the most

important settings that are essential to style the hair .

If you want to know more about these settings please take a look at

Autodesk Maya Hair System Node:

http://help.autodesk.com/view/MAYAUL/2015/ENU/?guid=Hair_Nodes_hairSystemShape

Autodesk PFX Brush :

http://knowledge.autodesk.com/support/maya/learn-explore/caas/CloudHelp/cloudhelp/2015/ENU/Maya/files/Paint-Effects-and-3D-

Paint-Windows-and-Editors-Paint-Effects-Brush-Settings-htm.html