Interactive rendering (or "IPR", also called "re-rendering" or "live rendering") uses the progressive refinement mode of path-traced rendering to continually update a render as aspects of a scene are changed. It is, fundamentally, the same as rendering, but all manner of interactive, real-time edits are possible during an IPR session. Rendering of the image is restarted after each edit (returning to a noisy image again), but the renderer keeps the scene loaded and ready to render.

During an interactive rendering session in RenderMan, you can:

• Move the camera view
• Model objects
• Import and export assets (Alembic, RIB archives, USD, etc.)
• Add and delete lights
• Change light parameters, re-position lights
• Change light linking
• Change material bindings and edit material and pattern parameters
• Change integrators and parameters
• Edit geometry attributes, even displacement.
• ...most anything you can think of.