Autodesk 12812-051462-9011 User Guide 3 - Page 1055

Filter Sets the filter to use for sharpening caustics. Can equal Box, Cone, or Gauss. The Box option requires less rendering time. The Cone option makes caustics appear sharper. Default=Box. The Gauss filter uses a Gauss (bell) curve, and can be smoother than the Cone filter. Filter Size Controls the sharpness of caustics when you choose Cone as the caustic filter. This value must be greater than 1.0. Increasing the value makes caustics more blurry. Decreasing the value makes caustics sharper, but also slightly more noisy. Default=1.1. Opaque Shadows when Caustics Are Enabled When on, shadows are opaque. When off, shadows can be partially transparent. Default=on. Opaque shadows render more quickly than transparent shadows. Global Illumination (GI) group These settings let you control the usage of photons by mental ray for generating global illumination on page 6261. By default, all objects generate and receive global illumination. The settings for generating and receiving GI are located on the Object Properties dialog > mental ray Panel on page 322. NOTE In order to render global illumination in mental ray, the photons must be able to bounce among two or more surfaces. This can be accomplished by having a single object with some concavity in its surface that's exposed to the light source, or at least two objects, and at least one object must be set to receive global illumination (see mental ray Panel (Object Properties Dialog) on page 322). Otherwise you'll receive error messages and no photons will be stored. Enable When on, the mental ray renderer calculates global illumination. Default=off. Multiplier/color swatch Use these to control the intensity and color of the indirect light accumulated by global illumination. The defaults, 1.0 and white, produce physically correct rendering. This is useful for adjusting the contribution of the GI effect, thus improving the quality of an image. Maximum Num. Photons per Sample Sets how many photons are used to compute the intensity of the global illumination. Increasing this value makes global illumination less noisy but also more blurry. Decreasing this value makes global illumination more noisy but less blurry. The larger the Samples value, the greater the rendering time. Default=500. 6310 | Chapter 20 Rendering