Interactive rendering (or "IPR", also sometimes called "re-rendering") in PRMan's RIS mode is the next step in the evolution of progressive refinement path-traced rendering via the raytrace hider, introduced in PRMan 18. It is, fundamentally, the same as rendering, but all manner of interactive, real-time edits are possible during an IPR session.
During an interactive rendering session in the RIS mode of PRMan, you can:
- Move the camera and change its parameters
- Add and delete lights
- Change light linking
- Change material bindings and edit material and pattern parameters
- Change integrator and projection bindings and parameters
- Edit geometry attributes
The major restriction is geometry. Geometry cannot be added, deleted, or moved during interactive renders, yet.