Autodesk 12812-051462-9011 User Guide 3 - Page 1027

with the background color, this option replaces only pixels used by the re-rendered selected objects. Subset pixel rendering is particularly useful when performing iterative rendering and refinement of lighting, shadows, and other scene elements for a particular object or set of objects in the scene. It lets you re-render repeatedly to view the results of isolated changes without disturbing the rest of the rendered output. This setting is also available on the Rendered Frame Window, as Subset Pixels (of selected objects) on page 6081. Ray-Trace Acceleration: Parameters for the BSP Method Rendering menu/main toolbar > Render Setup > Render Setup dialog > Renderer panel > Rendering Algorithms rollout > Raytrace Acceleration group > Choose BSP as the Raytrace Acceleration method. When you choose BSP as the Raytrace Acceleration method on the Rendering Algorithms rollout on page 6277, the parameters described here are displayed. BSP stands for Binary Space Partitioning. NOTE If the scene contains too many faces (triangles) to fit in a tree of the size specified by the Size and Depth parameters, mental ray disregards the Size value and creates larger leaf nodes. This can significantly slow down rendering. To avoid this problem, increase the value of Depth. Interface Size Sets the maximum number of faces (triangles) in the leaf of a BSP tree. Increasing the Size value reduces memory consumption but increases rendering time. Default=10. Depth Sets the maximum number of levels in the BSP tree. Increasing the Depth value reduces rendering time, but increases memory consumption and preprocessing time. Default=40. 6282 | Chapter 20 Rendering