Camera Projections are the lens through which RenderMan views the digital scene. RenderMan comes with some built-in camera projections: perspective, orthographic, sphere, cylinder, and torus. Additionally, you can create custom projection plugins using C++. Both types of projections are available in RenderMan for Katana.
Built-in Camera Projections
Built-in camera projection plugins are available via PrmanGlobalStatements:
The default projection type will use the projection specified either in the CameraCreate node or the Alembic_In camera.
Projection modifiers can change one or more aspects of the camera projection. For example, PxrRollingShutter modifies the time samples on the camera rays, without adjusting the ray origin or direction. Projection modifiers can only be used with a default projection - perspective or orthographic.
Custom Projection Plugins
Custom Projection plugins, such as PxrCamera, are created with a Material or PrmanShadingNode and assigned to
/root with a MaterialAssign node. Just like projection modifiers, only one custom projection plugin can be used at a time in conjunction with a default projection.