Motion blur can enhance the realism of a rendered animation by simulating the way a real-world camera works. A camera has a shutter speed, and if significant movement occurs during the time the shutter is open, the image on film is blurred.

Autodesk VIZ provides several ways to generate motion blur. Scene motion blur is one. Image motion blur is another. For most purposes, image motion blur give better results than scene motion blur. Use scene motion blur whenever you want to strongly emphasize rapid motion. You can use both image and scene motion blur in the same rendering.

(Another option, object motion blur, is not meant to simulate a camera, but to improve the rendered appearance of fast-moving objects.)

Scene motion blur creates trails behind all moving objects by rendering the entire scene at multiple time increments within each frame, and then creating the frame by compositing the multiple images together.