2008

Raytrace Acceleration Group
Method The drop-down list sets which algorithm to use for
raytrace
acceleration
on page 7905 . The other controls in this group box change,
depending on which acceleration method you choose. These are the
alternatives:
■ BSP (the default)
The BSP method has Size and Depth controls. See
Ray-Trace Acceleration:
Parameters for the BSP Methods
on page 6141 .
This method is the fastest on a single-processor system. Use it for
small-to-medium size scenes on a single processor. BSP is also the best
method to use when ray tracing is turned off.
■ Grid
The Grid method has Size, Depth, and Resolution controls. See
Ray-Trace
Acceleration: Parameters for the Grid Method
on page 6142 .
This method uses less memory than BSP. It is also faster than BSP on
multiprocessor systems.
NOTE If you attempt to render motion blur with the Grid method active, the
mental ray renderer automatically switches to the BSP method. This happens
in the MI file but is not reflected in the 3ds Max interface.
■ Large BSP
The Large BSP method has the same controls as BSP. See
Ray-Trace
Acceleration: Parameters for the BSP Methods
on page 6141 .
This method is a variant of the BSP method. Portions of the partitioning
tree it uses can be swapped in and out of memory. This enables mental to
render very large scenes, at a cost of ray-tracing time. Use this method for
very large ray-traced scenes, and also when Use Placeholder Objects is
turned on (see
Translator Options Rollout (mental ray Renderer) on page
6122 ). Use Placeholder Objects is recommended when you are doing
distributed rendering on page 6131 .
Trace Depth group
Trace depth controls the number of times a light ray can be reflected or
refracted. At 0, no reflection or refraction occurs. Increasing these values can
increase the complexity and realism of a scene, at a cost of greater rendering
time.
mental ray Renderer | 6121