GroIMP provides a GPU-based ray tracer based on a Monte-Carlo method. It utilizes available computing resources through OpenCL. During simulation, each object keeps track of the amount of light it absorbs. Per object, it either computes a fully discretized absorption spectrum or several integrated weighted spectra, which are subsequently used in a photosynthesis model.

GPUFlux implements on GPU three well known, physically based rendering algorithms: Path Tracing (PT), BiDirectional Path Tracing (BDPT) and Energy Redistribution Path Tracing (ERPT).