Autodesk 12812-051462-9011 User Guide 3 - Page 926

The initial quality stage performs repeated passes, which are shown in the dialog's progress bar. 2 Refine Iterations (All Objects) and Refine Iterations (Selected Objects) Because of the random nature of the sampling during the initial quality stage, some of the smaller surfaces or mesh elements in the scene might miss being hit by enough rays (or any rays at all). These small surfaces remain dark, and result in the appearance of "variance" or dark spots. To alleviate these artifacts, the Refine stage "regathers light" at every surface element. You can perform the Refine stage for the entire scene, or for selected objects in the scene. 3 Regathering Even after the Refine stage, it is still possible for visual artifacts to appear in a scene because of the topology of the original model. These artifacts sometimes appear as shadow or light "leaks." To eliminate even these model-based artifacts, a third, optional refinement stage known as Pixel Regathering occurs at the time of image rendering. This involves a final "regather" process for each pixel of the image. Regathering can add a considerable amount of time to the rendering of a final image, but it also produces the most detailed and artifact-free images possible. One benefit of using Regathering is that it means the initial modeling and mesh resolution don't need to be nearly as "refined" or "tight" as would otherwise be required. Radiosity Workflows The following sections describe how to set up a scene for use with radiosity. Set Units Correctly Before Processing Radiosity For imported geometry, you must make sure that units are consistent in your scene before processing radiosity (for example, a wall is 8 feet high, not 8 kilometers high). Units in 3ds Max must match the units of the model because the radiosity engine always uses an inverse square falloff for lights. Therefore, distance is crucial. To make sure your units are setup correctly, use the Units Setup dialog on page 7809. The Scene Unit is the most important unit in this dialog. This is the Default Scanline Renderer Controls | 6181