You can set any of the following options to optimize the render of motion blur.

• Reduce the scene's shutter Speed to speed up motion blur calculations.

• Select mental ray's Scanline or Rasterizer algorithms to render a faster motion blur than is done with raytracing.

• If your scene has a lot of motion blur, you may need to increase the sampling in mental ray's Rendering Aliasing options.

  Try a value such as 0, 2 or 0, 3 (Min and Max Levels). However, before you increase these sampling settings, first try adjusting the Motion Samples.

  Use mental ray's Motion Samples to fine-tune the motion blur effect instead of the Sampling Contrast. You can achieve good quality with little impact on render performance.

• Use the mental images production 2D Motion Blur and Motion Vector (mip) shaders, or any third-party 2D motion blur plug-in instead of raytraced or scanline motion blur algorithms. 2D motion blur is handled as an output shader and applies the motion blur effect after the image is rendered.