For procedural primitives, RenderMan for Blender supports both procedural primitive DSOs and RunProgram. For more information on how to write/compile these types of procedural primitives see this section in the Developer's Guide.

Adding

You can add either type of procedural primitive from the Add menu.

RunProgram

To pass arguments to your RunProgram look in the object properties , under the RenderMan Geometry panel; there should be a RunProgram subpanel.

DSO

To pass arguments to your RunProgram look in the object properties , under the RenderMan Geometry panel; there should be a Dynamic Load DSO subpanel.