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Desktop Radiance 2.0 BETA TutorialThis tutorial is intended to familiarize the beginninguser with the Desktop Radiance user interface. Itdescribes a typical process for creating a simple roomwith one window, placing a desk and luminaire, settingup a camera and starting a simple interactive rendering.Before beginning, you must install AutoCAD, DesktopRadiance and Optics5 as described in the InstallationInstructions. For more detailed and in-depthinformation about Desktop Radiance, you may refer tothe online help manual, the Desktop Radiance websiteat http://radsite.lbl.gov, and the Desktop Radiance emailand web-based support group athttp://groups.yahoo.com/group/DesktopRadiance.This Tutorial is written for both AutoCAD r14 andAutoCAD 2000. Some steps may appear differentlythan shown, depending on your set up and system.

Legend:The ↵ symbol is used for “carriage return” or “enter”and in AutoCAD is often interchangeable with a“space”.Boldface text in Helvetica is used for commands to betyped into the AutoCAD command prompt.The “ ’ “ (single quote in bold) is used for feet and the ““ “ (double-quote in bold) for inches.Boldface text between “<“ and “>“ brackets in Timesfont is used for actions to be performed in theAutoCAD graphics window.Menu commands are indicated with: MenuÅSubmenu

1. Launch Desktop Radiance by selecting the DesktopRadiance 2.0 icon from the StartÅProgramsÅDesktop Radiance 2.0 menu group.

2. Depending upon your AutoCAD setup, you may bepresented with the Startup Wizard (Figure 1). If so,click the “Start from Scratch” button, then OK to anew drawing in English units.

Figure 1. AutoCAD Startup Screen.

3. You will then see the Desktop Radiance Preferencesdialog box (Figure 2). Set the drawing units toInches to agree with English units selected earlier inthe Startup Wizard. Then click OK to return to thedrawing. If you are not familiar with how to setupyour drawing or units, see AutoCAD’s User Guide

“Chapter 2 – Organizing Your Project –UsingOther Setup Methods –Setting Units Style” in theAutoCAD help system.

Figure 2. The Desktop Radiance Preference dialog box

4. Type ddunits and select “architectural” to changethe display to the English feet and inches format.1

5. Draw a box to represent the walls, floor and ceilingof the room. box ↵ 0,0,0 ↵ 10’,10’,10’ ↵

6. Explode the box so that you can operate onindividual surfaces: explode ↵ <select box> 2

7. Change the view to axonometric with ViewÅ3DViewpointÅTripod. Move your cursor to theposition indicated by the small “+” mark near thecenter of the cross-hairs in Figure 3. <positioncursor near the cross-hairs between the originand outer circle at 8 O’Clock> click the leftmouse button.

Figure 3. The AutoCAD “tripod” showing theapproximate desired position of the cursor within cross-hairs.

8. What you see now should be similar to Figure 4.

1 It is AutoCAD convention that the units display formatof “architectural” corresponds to inches as the unit ofmeasure for the drawing. Selecting a different unit inthe Desktop Radiance preferences dialog whenAutoCAD is set as “Architectural” will giveunpredictable results.2 Desktop Radiance 2.0 BETA currently does notsupport complex ACIS solids such as objects that resultfrom the “subtract”, “intersect”, or “union” commands.

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Figure 4. After changing the view using the tripodcommand.

9. Attach a dark floor material: RadianceÅMaterialsÅAttach Material… < click on floorpolygon>↵

AutoCAD Tip: If you have difficulty selecting a surfacewhich is co-planer with another, AutoCAD provides a“cycling” feature which highlights one co-planer entity ata time. For example, if you ctrl+left click once on theedge where a wall meets the ceiling, AutoCAD will showat the prompt: “<CYCLE ON>”. Then if you left click(without the control key) on the edge, either the wall orthe ceiling will be highlighted. If you left click again, theother will be highlighted. For more information on how to select/deselect entities,see “Chapter 7 -- Editing Methods” in the AutoCAD helpsystem.

Figure 5. The Materials Library dialog box.

10. The “Materials Library” dialog box appears(Figure 5). Select blue-gray material by using theFind command. Type blue-gray in the search box.When the material is found and highlighted, clickATTACH .

11. Select wall surfaces to attach material: RadianceÅMaterialsÅAttach Material…select all wallpolygons , ↵

12. The “Materials Library” dialog appears. Select“yellowish paint” material by using the Findcommand as before, then click ATTACH

13. Select ceiling surfaces to attach material:RadianceÅMaterialsÅAttach Material…select ceiling polygon ↵

14. The “Materials Library” dialog appears. Select“off-white” material by using the Find command asbefore, then click ATTACH

Notes: You will not see the attached Desktop Radiancematerials in AutoCAD entities. They will only bevisible (rendered) in a Desktop Radiance simulation.To see if you have successfully attached materials to theceiling and walls, use RadianceÅMaterialsÅShowall attached materials. This will highlight all thesurfaces which have attachments. For morecomplicated drawings, the RadianceÅToolsÅShowAll Unattached maybe a more suitable tool.A surface in Desktop Radiance is considered infinitelythin and can have only one material attached to it. Itcannot have two different materials, one on the frontand one on the back. Therefore surface normal foropaque surfaces is irrelevant.

Creating a wall with a window opening15. Delete the far right wall to make way for a wall

with a window: erase <select the east wall> ↵(See note above on “cycling” if you have troubleselecting a particular wall surface).

16. Set the height of the sill for our window: thickness↵ 3’ ↵

17. Draw the portion of the wall below the window sill:line <select far end corner (A) of floor> <selectnear corner (B) of floor> ↵. The line that isdrawn will be the 3' high (thickness in AutoCAD)sill. See Figure 6 and Figure 7.

Figure 6. The room before drawing in 3' sill.

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Figure 7. The room after drawing 3’ sill.

18. Set the height of the window: thickness 5’ ↵19. Draw the wall on either side of the sill: line ↵ end ↵

<select the far vertex on top of the wall portioncreated earlier (C)> near ↵ <select a point a fewfeet from the corner (D) > ↵

20. Repeat the above step for the opposite side, drawingthe wall from vertex (F) to (E) and you will havesomething resembling Figure 8.

Figure 8. The room with two side walls.

21. Set the height of the window “head”: thickness 2’ ↵22. Draw the wall header: line ↵ end <select vertex

(G)> end <select vertex (J)>. Now in your drawingall the wall surfaces should be modeled and looksimilar to Figure 9.

Figure 9. Room with all wall surfaces modeled.

23. Attach a material to these wall pieces:RadianceÅMaterialsÅAttach Material…<select the wall pieces created above> ↵

24. The “Materials Library” dialog box appears.Select “beige” (or any other color), then clickATTACH

Creating a glazing surface Now that you have created a wall with an opening, youwill place a properly oriented surface inside thisopening to represent a pane of glass, then attach aDesktop Radiance glazing to characterize the glassproperties. All Desktop Radiance glazings are idealizedas a single surface even if the glazing is made ofmultiple “panes” of glass. The “right-hand rule” is usedto determine the order in which the vertices of theglazing polygon should be created in order to properlyorient the surface normal.3

25. Create the glazing surface: 3DFACE, <select thefour vertices of the glazing using the “righthand rule”: (E) (I) (H) and (D). > ↵. See Figure10.

3 Imagine placing your right hand against the wall withyou thumb pointing into the space (the direction that thelight travels). Your four other fingers now curl in thedirection that the vertices should be created to obtain aproperly oriented surface.

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Figure 10. The room with glazing.

26. If you are not sure the surface normal is oriented inthe direction you intended, use:RadianceÅToolsÅAdjust Surface Normal<select the glazing surface created above>.The surface normal will then be displayed as a redarrow originating from the centroid of the 3DFACE.A properly oriented glazing surface will have itssurface normal pointing INTO the room, in thedirection that light travels from the brighter side tothe dimmer side of the glazing. To flip the surfacenormal, type “Yes” at the command prompt and hitRETURN.

27. Attach a glazing to this glazing surface:RadianceÅGlazingsÅAttach Glazing…<select the glazing surface created above> ↵

Figure 11. The Glazings Library dialog box.

The “Glazings Library” dialog box appears (Figure 11).Select “clear glass” (or any other glazing) then clickATTACH. The glazing is now attached to the surface.4

4 For glazings, the surface normal is important when theglazing is treated “as a light source” for the rendering.A glazing in Desktop Radiance is always modeled as asingle surface. Having two panes of glass close togetherdoes not efficiently simulate a double-pane glazing.Having a box (3Dsolid) to model glazing with thickness

Placing Furnishings28. Switch back to a plan view for inserting objects

into your drawing. Place a desk in the room:RadianceÅFurnishingsÅPlaceFurnishing…

Figure 12. The Furnishings Library dialog box.

29. The “Furnishings Library ” dialog box appears

(Figure 12). Scroll or use FIND to Select the“desk” object and click ATTACH Upon returning to the AutoCAD Graphic Editor thedesk should be shown next to the cursor, movingalong with it. Find a convenient location for thedesk and click the left mouse button (Figure 13).You may need to rotate the desk to be oriented inthe correct position. You can select a scaling factorif desired. Furnishings can be rotated and mirroredarbitrarily using the corresponding AutoCADcommands.

Figure 13. Room with desk.

is also incorrect. All glazings in the Desktop Radiancelibrary are designed to be attached to infinitely thin,single paned surfaces, regardless of their real-lifecounterparts.

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Placing luminaires30. Place a luminaire in the room:

RadianceÅLuminairesÅPlace Luminaire…

Figure 14. The Luminaires Library dialog box.

31. The “Luminaires Library ” dialog box appears(Figure 14). Select “pendant cone reflector” andclick ATTACH. Upon returning to the AutoCAD Graphic Editor theluminaire should be shown next to the cursor,moving along with it. Find a convenient location forthe luminaire and click the mouse. You may rotateand/or scale the luminaire if desired. The “rotationangle” specifies the orientation of the outputluminance pattern relative to the luminaire housing.You may need to move the luminaire to a moreconvenient location using the “ortho” mode, afterfirst placing the luminaire at the correct height. Ifyou have trouble with the AutoCAD Move commandor if you fail to mount the luminaire onto the ceilingplane, refer to the AutoCAD help system.Luminaires can also be rotated and mirrored with theusual AutoCAD commands. Rotating the luminaireblock will cause the luminaire aiming to change.You can inspect the aiming withRadianceÅLuminaireÅShow Luminaire Aiming<select the luminaire>. A red arrow will bedisplayed showing the direction of the luminaireaiming.

Figure 15. Room with desk, luminaire, and luminaireaiming arrow.

Setting up a camera32. Return to a plan view to make camera placement

easier: plan ↵ ↵33. Define the camera position:

RadianceÅAnalysisÅDefine CameraPosition (Figure 16)

Figure 16. The Camera Properties dialog box

34. Enter the name of this camera such as“V1”. Set the elevation (height) of the camera as5’, and a lens length of “20” mm is recommendedfor interior views. AutoCAD camera names arealways in UPPERCASE and may not have anyspaces. Then click OK.

35. Upon returning to the AutoCAD Graphic Editor thecamera should be shown next to the cursor, movingalong with it. Find a convenient location for thecamera, click the left mouse button, and then rotatethe mouse to adjust the rotation of the camera.When you are happy with where the camera ispointing, left click the mouse button again (Figure17).

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Figure 17. Room with camera inserted.

36. Make the camera we just created the current view:view R <V1>↵. The display should now change toa view from the inside of the camera looking in thespecified direction (Figure 18). The “ring” you seeis an approximation of the lens of the camera.5

Figure 18. The view through the “V1” camera.

Starting an interactive rendering Now that all surfaces in your drawing have materialsattached to them and you have a camera/view defined,you can start a Radiance simulation to produce arendering. At this point you should save your drawing.37. Save your AutoCAD drawing, naming it

Tutorial.dwg or equivalent. The default projectdirectory will be inside of the Desktop Radianceinstall directory.6

38. Select the surfaces to be included in the simulationand begin the geometry export:RadianceÅSimulationÅCamera (Figure 19).Click “Use the Current View” if the view inAutoCAD is currently that of view V1. If the view inAutoCAD is currently not that of V1, click “Select acamera” and then either use the pull down combobox to select your camera name or click on the “<“box to return to AutoCAD and select the camera.

5 You can use the standard “dview” commands to alterthe view if desired. If changes to this view are made, theyneed to be saved back to the view definition using thefollowing two commands: Save the view: ddview<click on “new” button> V1 <click on “saveview” button>, <click “yes” to overwrite>.6 The project directory is where the Radiance geometry,materials, cameras, and simulations are placed during the“synchronization” process. For more information, see theUser Manual.

Then select to export “All exportable entities inthe current drawing” then click OK.

Figure 19. The Camera Simulation dialog box.

39. Next you will need to give this particular scenario aunique name in the Define Scenario dialog box(Figure 20). Click Ok after defining the scenariowill start the export process.

Figure 20. The Define Scenario dialog box.

40. In the background, Desktop Radiance has created a

project directory with the same name as yourdrawing. Scene, geometry, and view informationyou have selected to export will be exported fromAutoCAD into files useable by Desktop Radiance.The AutoCAD text window scrolls by with variousmessages, and the Simulation Setup dialog boxappears (Figure 21).

Figure 21. The Camera Simulation Setup dialog box.

41. The scenario name at the top of the window showsthe name you provided for this scenario. Becausethis name is used as the base name for Radiance

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simulations, the name may only containalphanumeric and the underscore “_” character.Each time you initiate a simulation, you will be askedto provide a new, unique scenario name. Thescenario keeps track of all the settings and used foreach simulation.

42. Select the camera from the list of names. If in yourdrawing you have more than one camera, you can usethe pull-down menu to select another view. The“current” is what you see displayed in yourAutoCAD drawing at the time of the simulation.7

43. The “Accuracy” setting only contains a “medium”setting for this version. However, you can adjust therendering parameters under the “Advanced” buttonon the Simulation Setup dialog box to get a highquality rendering. The help document and onlineDesktop Radiance FAQs have more information onsetting up the parameters.

44. Select one of the pre-defined sky conditions, CIEClear, CIE Overcast, CIE Intermediate, or CIEuniform.

45. The Location combo box lists a few predefinedlocations. You can define your own locations byselecting “New…” from the bottom of the pull-downlist. In the “location” dialog box, specify the city andstate name, longitude, latitude and altitude from sealevel. Click “OK” to save this location. The newlocation is then available for later simulation in thisproject and others.

46. In the “Add New Location” dialog box (Figure 22),specify a city name. Then input the latitude andlongitude of the location you want to simulate andpick a corresponding time zone from the pull downmenu. Be aware of whether your time zone isobserving Daylight Saving Time. If not listed, pick“other” from the list and then enter the StandardMeridian for that location. See the DesktopRadiance User Manual for more information. If youdo not know the turbidity factor for your location,input 2.0, the value for a clear (non-polluted) sky.Click OK to return to the Simulation Setup dialogbox.

7 You can create “plan” and other orthographic viewtypes by using the “current” view.

Figure 22. The Add New Location dialog box.

47. Select the Month, Day, and Time for the simulationin the Simulation Setup dialog box.

48. Select the desired Simulation Quantity (luminanceor illuminance8) and select “interactive” as theSimulation Mode

49. Click the “start” button to begin the simulation.This initiates the synchronization of your projectfiles with the contents of the drawing.

50. The Simulation Manager dialog box (Figure 23)should appear momentarily. Wait for the interactiverenderer to appear. This can take a few seconds forsmall scenes or up ten minutes for very complexscenes.

Figure 23. The Simulation Manager dialog box.

51. A window called “winrview”9 should appear andbegin to refine an image over a period of less than aminute. If you have many glazings, light sources,

8 In simple terms, “luminance” refers to the lightreflected off a surface towards a specific direction,while “illuminance” refers to the light arriving at asurface from all directions.9 Winview is an interactive rendering tool suitable forpreviewing and validating your model, but not forgenerating high quality renderings. For high qualityrenderings select “batch” as the Simulation Mode in theCamera Simulation Setup dialog box (Figure 21). Formore information on Batch rendering, see the “Startinga batch rendering” section of this tutorial or theDesktop Radiance User Manual.

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or a very complex scene, this could take a bit longer.52. After tracing the first several dozen rays, the image

will be automatically adjusted to the averageexposure for this view (Figure 24). Your renderingwill appear slightly different from the one shownbelow depending on the time of day, location, sky,etc.

Figure 24. The Winrview interactive window.

53. The status (on/off) and placement of the toolbars iscontrolled with the “view” menu. Different views ofyour scene can be created by manipulating thevarious toolbar widgets. F/B, L/R, and U/D stand forFront/Back, Left/Right, and Up/Down positiondisplacements of the viewpoint. If the toolbars arenot visible, go to the view menu and toggle thetoolbar status.

54. You can move around in the interactive renderer byusing the different slider buttons, or by clicking onthe “V” button near the top of the window and thenproviding the view parameters numerically. Formore detailed help on using the view parametersdialog box, see the help topic in Desktop RadianceUser Manual.

55. To save the new view definition for use bysubsequent renderings based upon the same scenario,use the FileÅAppend View to RIF File command.“Append to the RIF file” makes a reference to thisview definition in the RIF file and creates a view filecontaining the view information. This will beexplained in more detail in subsequent steps.

56. You should now be at an “open file” browser dialogcalled “Append View to Rif File” (Figure 25).Select the file “<scenarioname>.rif” where thescenarioname is the unique scenario name youprovided when you started this interactive rendering(Figure 20). Click Save.

Figure 25. The Append View to Rif File browser.

57. A dialog box is opened and you need to enter analphanumeric name for this new view (Figure 26).Click OK when finished.

Figure 26. View name dialog box, input your new viewname here.

58. You should now be at another open dialog boxcalled Append View to View File (Figure 27).Here you have the option of overwriting theoriginal view or saving the new view file definitionwith a different name.

Figure 27. The Append View to View File browser.

59. Enter an alphanumeric name for the view and giveit the .vf extension. An appropriate file namewould be the name you entered in Figure 26 plusthe extension. Click Save when finished. A viewsaved this way is equal to that of a camera viewsaved in AutoCAD.

60. After clicking Save, you will return back toWinrview. You can save the interactively renderedimage by using the FileÅSave menu command.Note the naming convention for images is“Scenarioname_viewname.pic.” You can savethe image with a different name, but theDisplay/Analyze button of the Simulation Managerwill be unable to automatically find and display theimage. (You will need to open the Winimage

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program, select FileÅOpen yourself, and navigate tofind the name of your image).

61. To close winrview and exit, user either FileÅExit orclick the “close button” (x). Winrview will alwaysprompt you to save the image when closing even ifthe image has already been saved before. This isbecause the rendering does not stop once you savethe image but continues to refine until it is eitherfinished (status bar near bottom of screen reads“ready”) or the Winrview application is closed.

62. You will now return to AutoCAD and the SimulationManager dialog box. The scenario will be indicatedas “finished” under the “% Finished” column.

Starting a batch renderingThe following section will cover how to start a batchrendering. A batch rendering will yield higher qualityimages, is faster than an interactive rendering, and moreefficiently uses your computer’s resources. For this batchrendering, you will use the view file that was savedduring the Winrview interactive session.63. On the Simulation Setup dialog box, make sure the

previous scenario name is highlighted, then click theDuplicate button. This brings up another DefineScenario dialog box (Figure 20).

64. Enter a new unique scenario name in the box, clickOK.

65. The Camera Simulation Setup dialog box will appearagain (Figure 21). Here you can make changes tothe settings while the geometry remains the same.

66. Next to the Camera Name is the “available viewnames” pull-down field. Pull down and select thenewly saved view name. It should be the last one inthe list.

67. For Simulation Mode, select the radio button forBatch.

68. Click the Start button to begin the simulation.69. The Simulation Manager dialog box (Figure 23)

should appear momentarily. At this point a DOSwindow (Figure 28) will be visible on your Windowstaskbar. The batch rendering is running in a DOSwindow that is minimized on the window’s taskbar.

Figure 28. Dos window showing Radiance commands(minimized in the background unless you maximize it,disappears when the rendering is finished)

70. When the rendering finishes, the DOS window willdisappear. Click on Display/Analyze on theSimulation Manager to display your image with theImage Analyzer (Figure 29).

Image Analyzer (Winimage)The Image Analyzer is a stand-alone program that canbe run separately from the rest of the Desktop RadianceAutoCAD plug-ins. It is accessible throughRadianceÅToolsÅ Image Analyzer, or by goingthrough Window’s Start Å Programs Å ImageAnalyzer.

Figure 29. The Image Analyzer (winimage) applicationallows you to display and post-process Radianceimages.

71. You should now be inside the Image Analyzer andlooking at an image of your room (Figure 29).Note the naming convention isscenarioname_viewname.pic; Your room imagewill appear slightly different from the one shownand have a different name.

72. To adjust the exposure of the image to the averagefor the overall image, use the Image ÅExposure Å Image command. This will createan exposure that approximates the dynamic range

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of a printed photographic image (Figure 30).10 Notethe naming convention of the exposure adjustedimage is scenarioname_viewname_avg.pic.

73. This latter image is automatically created and saved.You can close it now by clicking on the (x) in theupper right hand corner.

Figure 30. Image with Exposure adjustment.

74. To generate an Iso-Lux or Iso-Candela plot of image

illuminance or luminance values, use the AnalysisÅ Falsecolor … command. This will bring up theFalsecolor dialog box (Figure 31).

10 There are two basic types of Radiance images (bothwith the .pic extension): ones that contain “real world”luminance values (also known as “raw” images) and thosewhose dynamic range has been compressed for displaypurposes. The “raw” images which come straight fromthe rendering engine contain the predicted “real-world”luminance or illuminance values as would be measuredwith a luminance or illuminance meter. These images canbe altered in ways that either preserve or lose theunderlying luminance values. All of the commands inWinimage under the “Image” menu preserve the originalsimulated lighting values in the image file and can befurther adjusted or analyzed in Winimage. A “flat” imageresults from operations in the “Analysis” menu. Theimage loses its “real-world” values and no longer containthe full dynamic range of the original “raw” image.

Figure 31. The Falsecolor dialog box.

75. You can display units in either Metric or Englishfor every image. However, an image renderedusing Simulation Quantity of Luminance shouldonly be displayed in Luminance, and an imagerendered using Simulation Quantity of Illuminanceshould only be displayed in Illuminance. Thechoice between rendering in Luminance orIlluminance was decided back at the CameraSimulation Setup dialog box (Figure 21).

76. The “Number of Divisions” and “Maximum Value”fields default to 8 and 1000, respectively.Depending on the time of day, view, and renderingparameters you had selected for your simulation,these may need to be adjusted accordingly.

77. “Show Pixel Extrema” set to Yes means thebrightest and dimmest spots will be noted in yourfalsecolor image. For this first falsecolor of yourroom, use the defaults and click OK.

78. In a few moments you will return to the ImageAnalyzer and the falsecolor image will appear(Figure 32). Note the naming convention for afalsecolor image isscenarioname_viewname_fls.pic.

Figure 32. The first falsecolor luminance image

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79. Excluding what is seen through the window, if yourfalsecolor is not showing a wide range of colors(from blue to red) then you should run falsecoloragain, this time adjusting the Maximum Value toreflect the conditions of your room. In Figure 32, wecan assume the Luminance value for most surfaces inthe room is between 6 and 300 Nits (Candela/meter2)because most of the surfaces are blue and light greenon the scale.11

80. For the second falsecolor attempt in this case, theMaximum Value will be lowered to 300.

81. Close the first falsecolor image and operate on theoriginal untouched image. It is incorrect to runfalsecolor on top of a falsecolor! You should neveruse commands under the “Analysis” menu on animage twice. With Maximum Value changed to 300,the result shows a wider range of colors (Figure 33).

Figure 33. Second falsecolor Luminance image withMaximum value set to 300.

82. When you are comfortable with this process, closethe falsecolor images, leave the original untouchedimage open, and go to Analysis Å Iso Contour.

83. The same dialog box (Figure 31) will appear. Editthe options if you wish then click OK. Theuntouched image you started with is now overlaid bycolored iso-contour lines (Figure 34). Note thenaming convention for an iso-contour image isscenarioname_viewname_iso.pic.

11 Nits is another name for the SI unit of measure forluminance and is equivalent to watts/steradian/meter2, orcandela/meter2. Obviously we use the name “Nits”because it fits nicely into the falsecolor and iso-contourimage legend.

Figure 34. Iso Contour image with “maximum value”set to 300 and “show pixel extrema” turned off.

84. As with the Falsecolor image, It is incorrect torun iso-contour on top of any image that hasbeen altered with the commands under the“analysis” menu. You should not run iso-contouron a falsecolor image and vice versa. When youare satisfied with your iso-contour image, close itand return to the original untouched image.

85. To generate a representation of how the image willappear considering the sensitivity and adaptation ofthe human eye, you can use the Analysis ÅHuman Sensitivity Å Image command. Theresulting image will show loss of visual acuity andloss of color saturation at low light levels, and willshow veiling glare around bright windows. It willalso adjust the overall image according to a humancontrast sensitivity function to more closely mimicthe human visual perception (Figure 35). Note thenaming convention for an image with HumanSensitivity applied isscenarioname_viewname_pcd.pic.

Figure 35. Image with Human Sensitivity applied.

86. Compare Figure 30 with Figure 35. An imagewith only an exposure adjustment (Figure 30)shows the ground plane and sky outside of thewindow as very bright and washed out. An imagewith human sensitivity applied (Figure 35) shows

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the ground and sky much more like how the humaneye would perceive them.12

87. If you would like to save the Radiance images in toother formats, use the FileÅSave as… AnyRadiance image, raw or analyzed, can be saved to.GIF, .BMP, .PICT (Macintosh), .EPS (gray-scale),or .TIFF file formats for printing. The menu itemprovides you with the usual browser dialog box toperform these operations.

88. These are the basic tools and commands of DesktopRadiance. For more on the advanced topics, pleaseconsult the Desktop Radiance User Manual.

89. Thank you for taking the time to learn DesktopRadiance.

12 The human sensitivity functions of the Image Analyzerare documented in the paper by Greg Ward called “AVisibility Matching Tone Reproduction Operator forHigh Dynamic Range Scenes” which can be viewedonline at http://radsite.lbl.gov/radiance/papers/index.html.While highly useful for generating an impression of whata human would experience, the algorithms have not beenrigorously validated and should be used with caution.