The Mesh Geometry Type setting is found on the shape node for all meshes and geometry within a Maya scene. This setting determines how Octane handles the geometry on each frame of the render. The four types are Global, Scatter, Moveable Proxy, and Reshapable Proxy.
Setting the correct geometry type is essential for optimizing the render and in some cases an inappropriate setting can cause the scene to render incorrectly or crash. When preparing a scene to render, it is important to go through the geometry and make sure this is set correctly. The setting is found in the Attribute Editor as well as in the Channel box for the geometry (figure 1)
Figure 1: The Geometry type settings found in the Channel box (left) and the Attribute Editor (right) for a mesh object.
In determining which mesh type setting to use for each piece of geometry consider what the geometry does in the scene:
- Global should be used for static geometry that does not move and is not deformed
- Scatter should be used for geometry that is instanced to particles
- Moveable Proxy should be used for geometry that is translated/rotated/ or scaled in the scene but not deformed
- Reshapable Proxy should be used for geometry that is deformed
Moveable and Reshapable geometry types are loaded for each frame of the animation as it is rendered by Octane. However Octane only takes the transformational information of Moveable Proxies into account as it renders subsequent frames, thus reducing computational overhead. Global geometry types are loaded only once which saves memory as Octane processes the scene.
Example: you have an animated scene with a furnished room, in which a skinned (deformable) character moves a chair from one point to another.
- What setting should be on the chair?
- What setting should be on the skinned (deformable) character?
- What setting should be on the rest of the static objects in the scene?
For Octane scene inside Maya, this example would look like the following:
- The moving chair geometry should be set to “Movable proxies“.
- All room furniture (except the moving chair) should be set to “Global“. This will produce static non-movable geometry which will be loaded only on the first frame and just reused in all subsequent frames. This geometry will take more time during the translation stage (but only in the first frame), however it will be rendered faster (samples per second speed will be higher).
- If particle instances are used to make the fibers of the carpet then the original geometry that is instanced to the carpet fibers should be set to “Scatter”.
- The chair geometry should be set to “Movable proxy“. In this case – the mesh will only be loaded in the first frame of animation sequence, and only the transform will be reloaded on all the other frames.
- The character mesh should be set to “Reshapable proxy“. In this case both the character’s transform and the geometry will be reloaded and re-evaluated every frame.