Rendering overlapping shapes with motion blur, any advice?

Hi all!

I did a rotoscope of a guy walking away from the camera. The rotoscope is a bunch of overlapping shapes and now i wish to render them out with motion blur activated.
But i notice that where shapes edges overlaps the motion blur of each shape is “added”, creating an odd effect on the final silouhette. Looks like Mocha renders the motion blur separately for each shape and doesn’t take in account the fact that there are overlaps.
Is there something i can do to alleviate this issue? What’ i’m missing?

Using Mocha Pro 4.x

Thank you! Umberto

Hi Umberto,

Can you send us a screenshot? It’s hard to give advice without seeing this.


Of course yes.

This is the shape configuration. Until i missed something, i set motion blur active on all shapes, 180 shutter degree.

This is the rendered matte. You can notice that the joints don’t blend well with the overall shape like if the motion blur were not computed on the overall silouhette but once for each shape then added toghether.


Hi Umberto,

Yeah, they don’t generate together, they are all competed according to their tracks. In your case, the setup of the shapes is causing some overlap issues. You might try narrowing the ends of the overlapping problems using the Über key and see if that helps hide the problems. Otherwise, you can export the shapes out without motion blur into your host and fake the motiont blur in your host instead of using Mocha’s motion blur.

I think those are your best options to try right now.

Got it.

I think i’ll go the export-shape-into-Fusion way.
Well… ok ok V5 would be far more Fusion friendly, now each time i touch something in Mocha i need to re-import all shapes manually :grimacing:

Thanks Mary!