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The following chart shows how much time it takes to for each renderer to build the light acceleration data structure depending on sample count.
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- 3Delight is slower to generate these samples. Meaning that for draft (high variance) renders Arnold and RenderMan/RIS are faster. For final renders (low variance) 3Delight becomes increasingly faster with the number of samples.
- Both Arnold and RenderMan/RIS produce biased images at low sample counts. More specifically: images are darker. This explains higher RMSE with low sample counts. 3Delight manages to keep the same energy overall independent on sample counts.
- Arnold, 3Delight and RenderMan/RIS rely on acceleration data structures to sample the geometric area lights. In Arnold and RenderMan, the algorithmic complexity to build those data structures is tied to – linearly, as the graph shows – to the number of samples as well as the complexity of the light. In 3Delight, only to the complexity of the light matters (time to first pixel for 3Delight was 2-3 seconds no matter how many samples there are).