Geometry shaders allow you to create geometry in the mental ray renderer at render time. All that’s stored in your scene is a simple placeholder that defines the position of the geometry — represented by a randomized wireframe cube.
Geometry shaders are ideal for things like feathers that involve many instances of identical geometry.
By using geometry shaders, Softimage keeps track of only the placeholder objects, reducing the complexity and memory requirements of the scene.
Where Do Geometry Shaders Come From?
Typically, you write custom geometry shaders for the specific needs of your production: feathers, leaves, scales, and so on. For more information about writing mental ray shaders, see the mental ray documentation (available in the Doc\mental_ray subfolder of the directory where Softimage is installed).
One geometry shader is provided as an example: Geo_Cube.Preset in the Data\DSPresets\Shaders\Geometry subfolder of the directory where Softimage is installed. As its name suggests, it creates a simple cube.
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Geometry shaders are good solution when you need many identical copies of simple geometry. However, if you use a geometry shader to create complex geometry, it can take a long time to render. This is because the geometry must be flushed and regenerated for each frame. This extra processing time is more noticeable when the geometry is complex. |
Autodesk Softimage v.7.5