RenderMan tackled some of the most complex rendering scenes yet attempted by Pixar, in the Oscar winning Coco. Find out how the RenderMan and Pixar production team collaborated to overcome incredible scene and lighting complexity. Léalo en Español!
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One the most complex aspects of the film was the scope and use of lights. 29,000 lights were used in the train station scene. The cemetery had 18,000 lights and the City of the Dead used 2,000 practical lights in RenderMan. The studio team used the RenderMan API to create 700 special point cloud lights, which, when expanded, is equivalent to 8.2 million lights.
"Anyway they came back after a little time and we tried the new schema, and we told them great - it
does now render
but it takes 1000 hours a frame to get anything that looks like something we might want,
and it was still really noisy." she explains. "When we showed the RenderMan team they were confused, - why would it take so long they asked? And then they looked at our setup and said 'wait a second - how many lights do you call 'a lot of lights' and I answered; at last count we had instanced our lights out to about 8 million lights. At that point we all went into a second round of R&D!"
After 6 months the Lightspeed and RenderMan team had a system that gives the effect of millions of lights and took the notional render time on the complex shots down from 1000 hours to 450 hours. The team continued and reduced this further to 125 hours and finally 75 hours a frame. With some additional work on the way the production team worked with the lighting in shots, the final per frame time at the end of production was just 50 hours per frame.