Compares no motion blur, standard motion blur and a technique I developed for creating cartoon motion blur with RenderMan.  I have exaggerated the cartoon motion blur to better illustrate its appearance.

Rendered using 3Delight, however any RenderMan compliant renderer should be able to achieve the effect.

What I'm doing to get this style of motion blur is to take the movement of the geometry between the shutter open and the shutter close and compress that movement so it happens between shutter open and half-way to shutter close.  Then from the half-way mark I hold the movement until shutter close.  Using multiple motion blur samples and tweaking the interpolation from the movement to the hold I can then control the appearance of the motion blur.

One of the nice things about doing it this way is I can still have standard motion blur happening in frame, so any camera movement can feel natural, while the character motion blur can be more cartoony.

Animation courtesy of DigitalFish.