Abstract: Interactive rendering requires a fast consistent framerate and rapid visual feedback. The render cache is a new method for achieving this using high quality renderers such as ray tracing that are usually considered too slow for interactive use. The method works by caching previous results produced by a renderer which are used to estimate the current correct image. It also tells the renderer which samples to render next in order to more rapidly improve future images.

The render cache provides visual feedback at a rate faster than the renderer can generate complete images, at the cost of producing approximate images during camera and object motion. By reprojecting the cached samples and optimizing render sampling, our system is better able to exploit temporal image coherence and enable the interactive use of slower renderers than was practical with previous methods. Moreover we accomplish this using a software only implementation without the use of 3D graphics hardware.