Creating custom dome geometry in Maya (The following procedure assumes a working knowledge of Maya)

Transcription

1 Creating custom dome geometry in Maya (The following procedure assumes a working knowledge of Maya) You may want to create custom environment geometry to match specific HDR images. An example of this is the Exhibit Hall environment. It uses a rectangular geometry instead of the usual hemisphere. This reduces the distortion which can be seen in the final result. Load the apf plug-in To create custom geometry in Maya, the Autodesk packet file plug-in must be loaded. In Maya version 7 and up: 1. Go to Window > Settings and Preferences > Plug-in manager 2. Click the Load button. 3. Browse to the appropriate Plug-in folder, located in C:\Program Files\Autodesk\Showcase2008\maya\ (There is a separate folder for each version of Maya which contains the Plug-In). Create geometry domes 1. Create a polygon object in the desired shape of the environment (for example, sphere with flattened bottom, cube with arched roof etc ). 2. Make the polygon object in two pieces: Dome and Ground, and name them accordingly. Note that Showcase relies on the naming of the Ground object to cast ground shadows. The average size of a Showcase environment is 2000cm (for automotive) 2. Group the Ground and Dome together as Room. Figure 18: Required naming convention of geometry for use as Showcase environment. Figure 19: Examples of some useful shapes for environments 3. Center the pivot point of the Room group to the center of the Ground object. 4. Center the Room at the origin:

2 Figure 20: Room is at the origin and its pivot point is centered on the Ground. 5. Modify > Freeze transformations on all the objects. 6. Export the Room objects as an apf file. 7. Flip all normals so that they face inward. To preview this in Maya, turn OFF double sided in the objects attribute editor (uncheck Attribute Editor > Render > Double Sided) The object representing the floor should be centered at the origin. 8. The geometry must have an orderly UV layout, that is, no overlapping UVs. Figure 21: Orderly, non-overlapping UV layout is required for the projected Surface Shader workflow Place the background image (The following workflow assumes that you have already used the built-in tools to create the IBL maps and background image.)

3 There are several ways to change the position of the background image as it appears on the dome: Edit the Dome s UVs Edit the Dome s material in Showcase Edit the background image placed on the dome The third method is described here: 1. A projected Surface Shader can be created in Maya to quickly provide a new background image which will fit perfectly onto the new geometry. In this case, the shading map is used to place the image, and mental ray is used to render a new version of the image which will fit the UVs of the model. 2. Assign a Surface Shader to all the surfaces in the geometry dome. a. Map the Surface Shader s Out Color to a file texture: select the As Projection option when doing so. b. Browse to the background image (in latitude longitude format) and use it as the file texture for the out color. c. In Maya, press the 6 hotkey (texture shading ON) to see the placement of the image on the geometry interactively. If the resolution of the image is not clear enough, increase it by switching to High Quality Rendering in the panel view options: Figure 22: Maya High Quality Rendering in the main view d. Use the Surface Shader s place3dtexture s handle to rotate and translate the image and align it correctly with the geometry.

4 Figure 23: The Shading Map s outcolor is positioned with the place3dtexture handle Bake the new background image using mental ray 1. Select all the dome geometry and then: a. Right-click on the dome geometry and select Baking > Edit attributes > texture. This opens the Bake Set window. Set the attributes as shown below:

5 Figure 24: Mental Ray Bake Set attributes. Note: The resulting image, named baked will be saved to \projects\default\renderdata\mentalray\lightmap b. To render the new image, select Lighting/Shading > Batch Bake > Mental Ray. This displays the Bake Set overrides. c. Click the Convert and Close button.

6 Figure 25: rendering the new background image via Lighting/Shading>BatchBake (Mental ray) d. Copy the image from \projects\default\renderdata\mentalray\lightmap to the new environment folder. Figure 26: Original image and the newly rendered layout to support the custom geometry

7 Undocumented Maya export to apf tip When exporting an apf file from Maya, note the following: The apf file has materials imbedded in it. Any images associated with this file will be found and displayed parametrically, if the images are in the same directory as the apf file. If a Shading Map effect is desired on the apf file, do the following: 1. In Maya, assign a Phong material. 2. Make all of its values the lowest possible values: (0 black, or move the slider to the left). 3. Map an image to incandescence. The result will be an apf file which will automatically have the equivalent of: Shading map in Maya Image Map in Showcase Figure 27: This set up of a Phong will be interpreted by Showcase as an Image Map material.

8 Appendix A: Hand editing the a3e file Prerequisites: This portion of the workflow assumes that the user has: Some experience editing xml, or other scripting language. A basic environment as created by Showcase s built in tools. This environment is named MyEnviro (for example). A custom geometry dome built in Maya A new background image rendered out of Maya which matches the custom geometry s UV layout. Note: Showcase scene files have an.a3s extension. Showcase environments have an.a3e extension. Edit the MyEnviro a3e file (which is xml format text) so that it references the new geometry. To do this, a sample file is useful for copying model and material statements from. Create a sample file with the new model and materials: 1. Create a new Showcase scene. 2. Import the custom dome geometry into the scene. 3. Press the M key to display material library. 4. Select the Ground object and assign an Image Map to it : a. Select Materials > Miscellaneous > Image Map. b. Source the new background image (previously rendered in Maya) and use it for the material s color. c. Rename the material Floor. 5. Select the Dome object and assign an Image Map to it. a. Source the new background image (rendered in Maya) and use it for the material s color. b. Rename the material Walls. 6. Save the scene. For example, name it TestEnviro. 7. Open both TestEnviro.a3s and MyEnviro.a3e in WordPad and compare the models section at the top. Note: The MyEnviro.a3e file has an additional light statement in the models section (highlighted in red below, the models are highlighted in blue). Do not overwrite the lighting statement in the next step. Copy the models from the test file to the environment file The simplified syntax of the models section of the a3e file looks something like this: <models> <import group <light type=" </light> </models> 1. Here is the full version of the Testenviro.a3s models section (has no lighting statement). Note that the <models> section can be very long in the case of custom geometry with many polygon objects. <models> <import group_based_names="1" src="generic.apf" original="c:\temp\generic.apf" name="generic.apf">

9 <child node="generic.apf:fileroot"> </import> <group urto="1" name="generic.apf:fileroot"> <child node="generic.apf:room"> </group> <group urto="1" name="generic.apf:room"> <child node="generic.apf:ground"> <child node="generic.apf:dome"> </group> <group urto="1" name="generic.apf:ground"> <child node="generic.apf:ground-mesh"> </group> <lod_group urto="1" name="generic.apf:ground-mesh"> </lod_group> <group urto="1" name="generic.apf:dome"> <child node="generic.apf:dome-mesh"> </group> <lod_group urto="1" name="generic.apf:dome-mesh"> </lod_group> </models> a. Compare this to the MyEnviro.a3e models section: <models> <import group_based_names="1" src="env.apf" original="env.apf" name="env.apf"> <child node="env.apf:fileroot"> </import> <group urto="1" name="env.apf:fileroot"> <child node="env.apf:env"> </group> <group urto="1" name="env.apf:env"> <child node="env.apf:ground"> <child node="env.apf:dome"> </group> <group urto="1" name="env.apf:ground"> <child node="env.apf:ground-mesh"> </group> <lod_group urto="1" name="env.apf:ground-mesh"> </lod_group> <group urto="1" name="env.apf:dome"> <child node="env.apf:dome-mesh"> </group> <lod_group urto="1" name="env.apf:dome-mesh"> </lod_group> <light type="directional" name="exhibition_2light"> <parameter type="string" name="castsshadows" value="true">

10 <parameter type="string" name="explicitlighttype" value="directional"> <parameter type="double3" name="lightcolor" value=" "> <parameter type="double3" name="lightcolor" value=" "> <parameter type="double4" name="lightdirection" value=" "> <parameter type="double4" name="lightposition" value=" "> </light> </models> 3. Paste the models section from the TestEnviro.a3s (marked in blue) into MyEnviro.a3e. 4. Save the edit s to myenviro.a3e and test that the environment still loads in Showcase (the materials assignments will be lost at this point). Copy the materials and material assignments from the test file to the environment file 1. Here is an example of a materials section of an a3s file. <materials name="miscellaneous"> <material type="a3s::unlit" name="image Map[0]" label="floor"> <parameter type="string" name="diffuseibl" value="none"> <parameter type="string" name="diffuselight" value="none"> <parameter type="string" name="diffusesource" value="texture"> <parameter type="string" name="specularibl" value="none"> <parameter type="string" name="specularlight" value="none"> <parameter type="string" name="specularsource" value="none"> </material> <material type="a3s::unlit" name="image Map" label="walls"> <parameter type="string" name="diffuseibl" value="none"> <parameter type="string" name="diffuselight" value="none"> <parameter type="string" name="diffusesource" value="texture"> <parameter type="string" name="specularibl" value="none"> <parameter type="string" name="specularlight" value="none"> <parameter type="string" name="specularsource" value="none"> </material> </materials>

11 2. Copy paste the entire materials section from the test file and use it to overwrite the materials section in the MyEnviro.a3e file. 3. Do the same for the material assignments: <material_assignments> <material_assignment visible="" material="miscellaneous::image Map" target="drive.apf:dome-mesh"> </material_assignment> <material_assignment visible="" material="miscellaneous::image Map[0]" target="drive.apf:ground-mesh"> </material_assignment> </material_assignments> Note that the material is assigned to the dome using its name, not its label; the label is what you would see as the material name within Showcase, but the under the hood name of the material is Miscellaneous::Image Map in this case. Its label is Walls. 4. Save the edits to MyEnviro.a3e, and load the file into a new Showcase session to preview MyEnviro. 5. Align the environment IBL to the custom geometry dome. 6. In the process of creating and exporting a custom dome Set the default light direction for the new environment Showcase environments and materials can be affected by an environment light. When this control is ON, the light and shadow direction is read from the environment (unless you have specifically overridden it for your scene by changing the value in the aforementioned control). To get the appropriate positional values for the light in the MyEnviro.a3e file, you must: 1. Create a new Showcase scene. 2. Switch to MyEnviro. 3. Import an object into the scene and assign a reflective material to it. (Materials > Miscellaneous > IBL Reflection Effect) 4. Switch on scene shadows. (Scene > Environment Lights and Shadows > Illuminates and Casts Shadows) 5. Position the light so that it matches the direction of your IBL images. 6. Move the shadow until it looks right. 7. Alternate method: a. Face the reflective object. b. Find the reflection of the sun in the object. (That is, position the camera so that the environment light is behind you.) c. Ctl-click to place the highlight. 8. Avoid making the light very close to the horizon, and thereby casting excessively long shadows. 9. Save the scene as MyEnviro_lightPosition.a3s. 10. Open the MyEnviro_lightPosition.a3s file in WordPad and look for the lightposition statement (at the top of the file, at the end of the models section).

12 a. Copy the following positional information (highlighted in red): <light type="directional" name="genericlight"> <parameter type="string" name="castsshadows" value="true"> <parameter type="string" name="explicitlighttype" value="directional"> <parameter type="double4" name="lightcolor" value=" "> <parameter type="double4" name="lightdirection" value=" "> <parameter type="double4" name="lightposition" value=" "> </light> b. Paste this positional information from MyEnviro_lightPosition.a3s into the same respective location in MyEnviro.a3e. c. Save the file and test it in Showcase on a new scene. Turn on scene shadows and import an object to confirm that the shadows appear in the correct location for MyEnviro. Appendix B: Supplementary workflows Hand editing a copy of an existing environment One of the simplest ways to customize an environment is to start with a copy of another environment. This copy can be made from within Showcase by right-clicking on an environment and then selecting Save to Environment Library. For this example, assume that the generic environment was copied, and the IBL maps were also copied from the common folder. Alternately, the folder itself can be manually copied from an explorer window. In this latter case, the copied environment will need the following edits: 1. Rename the environment folder: TestEnviro 2. Rename the environment.a3e file inside this folder: TestEnviro.a3e 3. Edit the TestEnviro.a3e file in WordPad and change the header name : Before: <?xml version="1.0" encoding="utf-8"?> <environment_description name="generic" image="generic.tif"> After: <?xml version="1.0" encoding="utf-8"?> <environment_description name="testenviro" image="generic.tif">

13 Figure28: Generic environment s folder contents. Note that the IBL maps for this environment are not located here. For this example, it is necessary to copy the IBL maps from the support\environments\common folder. Figure29: Typical contents of an environment folder (Night Plaza shown) Note that the.mayaswatches folder contains pre-rendered material swatches. It is optional to include this or not. Changing the environment s icon In Showcase you can set image for any custom environment. This is the simplest way to create a new icon. You may opt to edit the environment s icon, in this case Generic.tif, in Photoshop (to add text or a logo). Be careful not to remove the icon s transparency: 1. Ctl-click the icon s layer to select it. 2. Open another image which represents the new environment (for example, a saved image of a sphere in the environment). 3. Select the image and copy it to the clipboard. 4. Ctl-Shift-V to paste the image into the Generic.tif. 5. Ctl-T to transform the pasted image into place (make it smaller). 6. Ctl-E to merge the pasted layer down. 7. Save the image and rename it TestIcon.tif Editing the a3e file to source the new icon 1. Open the testenviro.a3e file in WordPad. Before: <?xml version="1.0" encoding="utf-8"?> <environment_description name="testenviro" image="generic.tif"> After: <?xml version="1.0" encoding="utf-8"?> <environment_description name="testenviro" image="testicon.tif"> 2. Launch Showcase and verify that the copied environment can be displayed, and appears with its new name and icon. Changing the IBL maps At this point, the images that make up the environment can be safely edited.

14 These images are HDR (High Dynamic Range). It is common to encounter HDR images in the following formats:.hdr,.tiff,.exr. Showcase supports: a..hdr, both reading and writing b. and.exr, just reading c..tiff (32-bit per channel) is unsupported A common edit is to switch all the IBL maps with new ones. These new maps may have been created by Showcase, HDRShop, Photoshop, or ATI s CubeMapGen. Refer to the help documentation for the specifics on optimal resolutions for these images. For the purposes of this example, assume that there are four new maps which are to replace the existing ones: NewTest_background.png This is a latitude longitude normal image such as a.jpeg. tiff (8-bit/channel) or.png Reflect_new.hdr vertical cross Diffuse_new.hdr vertical cross Specular_new.hdr vertical cross The IBL maps are in the Library environments are currently in.exr format to save on disk space. If the new replacement maps are in a different format, the testenviro.a3e will need to be edited accordingly: 1. Scroll to the bottom of the.a3e file and look for: <lighting type="ibl" name="genericibl"> <cube_map name="reflect"> <image name="cube" src="../common/reflectcommon1.exr"/> </cube_map> <cube_map name="diffuse"> <image name="cube" src="../common/diffusecommon1.exr"/> </cube_map> <cube_map name="specular"> <image name="cube" src="../common/specularcommon1.exr"/> </cube_map> </lighting> 2. Change to: <lighting type="ibl" name="genericibl"> <cube_map name="reflect"> <image name="cube" src="reflect_new.hdr"/> </cube_map> <cube_map name="diffuse"> <image name="cube" src="diffuse_new.hdr"/> </cube_map> <cube_map name="specular"> <image name="cube" src="specular_new.hdr"/> </cube_map> </lighting> Note: The../Common/ was edited out. This is because the IBL maps were copied from the common folder to their current location with the TestEnviro folder. 3. Test that the new files are showing up in Showcase.

15 Changing the background image 1. To change the background image, it is necessary to edit the material which is assigned to the dome geometry. Look for the materials section (at the bottom, just above the lighting) : <material name="backdrop" type="unlit"> <parameter name="diffusesource" type="string" value="texture"/> <parameter name="diffusetonemap" type="string" value="value"/> <parameter name="ibltone" type="string" value="global"/> <parameter name="diffusetexture" type="string" value="generic.png"/> <parameter name="minfilter" type="string" value="linear"/> <parameter name="magfilter" type="string" value="linear"/> <parameter name="sided" type="string" value="single"/> </material> And change it to (overlook the line wrap below): <material name="backdrop" type="unlit"> <parameter name="diffusesource" type="string" value="texture"/> <parameter name="diffusetonemap" type="string" value="value"/> <parameter name="ibltone" type="string" value="global"/> <parameter name="diffusetexture" type="string" value="newtest_background.png"/> <parameter name="minfilter" type="string" value="linear"/> <parameter name="magfilter" type="string" value="linear"/> <parameter name="sided" type="string" value="single"/> </material> 2. Test that the new background is showing up in Showcase by switching to another enviro and then back. Appendix C: Troubleshooting It is important to test any changes to a hand edited environment every step of the way: a single syntax error will break the file. Showcase saves explicit paths to images and apf files. If you are planning to share your new environment with another user, you may want to edit out these explicit paths. Showcase will look in the current environment folder for any images/files regardless. In Showcase, make sure that the IBL reflections are aligned with the visible background: 1. Import a sphere and assign an IBL Reflection Effect material. 2. Press the Home key to get to the home view. This is the initial view seen when the environment is first seen. 3. Rotate the environment geometry to get the best possible view. (Most Showcase environments are rotated so that the main light source appears to be just over (and slightly behind) the users right shoulder.) 4. Save the changes to the environment. 5. Switch to a bird s eye view of the sphere. Rotate the Environment IBL to match the dome geometry s rotations (if any). 6. When previewing edits as they re made: a. Switch to another environment. b. Save any image edits done in Photoshop etc

16 c. Reload the environment. Editing the a3e files may require a restart of Showcase for changes to be seen. Editing the dome geometry requires a restart of Showcase for changes to be seen. Be aware of the operating system s tendency for one application to put a lock on files so that another application may not overwrite it. In this case, error messages are not always apparent.