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Pixars graphics pipeline for real-time preview rendering, based around Optix, is heading in the right direction

The question for all CG animators working with preview renders is always the same: how does it relate to the tinal render? The need for a consistent lighting and shading model is vital, so that decisions made based on preview translate in a predictable manner to final render.

For Pixar the option to adopt the new Nvidia OptiX system for interactive raytracing into the RenderMan pipeline has proved a successful venture. "We've been able to craft a consistent lighting and shading model between OptiX and RenderMan. Thus the OptiX real-time renders give us a real-time prediction of what the final render will look like," says Pixar's Bill Polson. "If we look at the preview and the final and squint, they are identical. If we look closely we see the final render has added detail and complexity that we cannot achieve (yet) on the GPU."

The move to incorporate Optix into the RenderMan pipeline is still ongoing and has meant Pixar's own production has changed slightly, but theres an air of coincidence about Pixar and Nvidia moving in the same direction.