Category: mental ray > Lightmap
Related Softimage shader: Sub-Surface Lightmap Write
This shader is the lightmapping shader that is used to create lightmaps for fast subsurface scattering effects. This shader creates a lightmap and stores the front and back surfaces, their depth, and irradiant light intensities in one or more specially formatted lightmaps.
You must manually generate the lightmap image for fast subsurface scattering effects created using the misss component shaders. For more information, see Generating Lightmaps for the misss Component Shaders.
| Name |
The name of the shader node displayed in the render tree. Enter any name you like, or leave the default. |
| lightmap |
Specifies a writable color texture. |
| depthmap |
Specifies a depthmap. |
| lightmap_group |
The name of the "scatter group" created with automatic lightmap generation. All objects and materials that use the same scatter group will scatter light into each other. |
| lightmap_size |
Specifies the size of the lightmap, expressed as a percentage of the final rendered image resolution. Normally, this value should not need to be higher than 50%. However, should the rendered image still contain artifacts, you can set it higher than this. |
| write_lightmap |
Not implemented -- reserved for future use. |
| scatter_bias |
Adjusts the light in the lightmap to favor back scattering (light from behind the camera scatters back towards the camera) when using negative values and forward scattering when using positive values. The technical range is -1 to 1, but generally only small values (-0.2 to 0.2) make visual sense. |
| input |
Pick the shader that actually samples the lighting in the model for the lightmap. Generally misss_lambert_gamma is used, but any illumination shader can be used, for example mib_illum_lambert or even experiment with mib_illum_phong and scattering of specular reflections. |
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