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- Only diffuse reflectors. The original test scene had a diffuse+specular surface but that generated a considerable amount of additional noise in Arnold. Since we want to concentrate on light sampling here, we decided to go for a simpler setup.
- We will disable any adaptive sampling so to make sure we have very close ray-counts.
- We will use only direct lighting to estimate the geometric area light contribution. In the statistics files for each renderer, one can see that we have only one path length.
- The light sources contain about 80K triangles.
- All Renders are done in Maya 2016.
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We will start by creating a "ground truth" image for each renderer (encouragingly, images produced by both 3Delight and Arnold are almost exactly the same). This image is generated by using a very large amount of samples so there is no more apparent noise. We will then render several images with varying amount of samples and measure the RMSE between these images and ground truth. Timings and statistics will be taken collected at each render. Having this data will allow us to draw a conclusion about the convergence rate and general performance.
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We use a 1x1 pixel sample in all renderers to isolate the light sampler. Adaptivity is disabled as well as all additional bounces. This is done so to isolate the light sampler. In Arnold, the light samples are attributes of the geometry. In RenderMan/RIS the light samples are attributes on of a custom shape. In 3Delight, the light attributes are on Maya's area light.
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