The Render Manager > mental ray (Global Renderer)
The Render Manager > (expand a pass) > mental ray
Set the current pass and choose Render > Render > Renderer Options from the Render toolbar.
Tab: Render Type [Properties Reference]
For more information about optimizing motion blur, see Optimizing Motion Blur.
Options: Convert Textures to Memory Maps [Properties Reference]
The Scene Motion Blur Settings define the point in time when the geometry and its motion transformations and motion vectors are evaluated: this data is then pushed to mental ray.
You can use the mental ray Shutter and Delay options to tweak the size and length of the motion blur trails (without re-evaluating the geometry and its motion data). This allows you to quickly "dial-in" settings, if needed, although they are not particularly accurate.
Motion-Based Displacement Quality
Options: Geometry [Properties Reference]
For moving objects with displacement, you can optimize the displacement approximation depending on how fast the object is moving by setting the Shutter Settings option. The automatic reduction of displacement detail on moving objects has a significant impact on rendering performance and memory consumption by cutting down on the typically huge amount of tessellation data that gets generated.
The displaced geometry should have a geometry approximation property applied to it and motion blur must be enabled for the render region and/or the render pass. See Applying and Editing Geometry Approximation [Scene Elements].
