2008

The coin on the right has Image Motion Blur applied
You can’t put image motion blur on objects that change their topology.
TIP When blurred objects overlap, sometimes blurring doesn't work correctly and
there are gaps in the rendering. Because image motion blur is applied after
rendering, it can't account for object overlap. To fix this problem, render each
blurred object separately, to a different layer, and then composite the two layers
using the Alpha Compositor in Video Post.
5960 | Chapter 18 Rendering