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Higher values shift texture mipmaps and dicing to coarser levels, or less detail. Negative increase details for both. Adjust in small increments.

Matte File

This is used to take a deep EXR to generate a matte for the termination of rays, in this way it's similar to a generalized clipping plane. The supplied file must be an EXR and can be Deep Data or a shallow EXR (with included alpha). If it is deep data then we set the rays to terminate where the data becomes opaque, cutting away anything behind them in the render. Semi-transparent areas are importance sampled based on the depth and level of transparency. This can improve performance by skipping shading and tracing of rays. If using a shallow EXR with alpha, we terminate rays on opaque areas immediately and allow them where transparent. If there is partial transparency we stochastically sample based on the level of transparency. The shallow EXR method operates a lot like a render mask.