Object catches "Edge" when sliding over boundary of two flush surfaces

[bbird5490]

Hi,

Please watch this short video first: https://user-images.githubusercontent.com/106173191/170082432-ac8b2b33-5621-4ec9-a099-508bae4fe88d.mov

Problem:

In the video you see a compound shape with 3 child shapes (red, green and blue in video). These convex child shapes form a surface that is perfectly flush. When I slide the yellow box over the surface it's seems that this box catches an edge when transferring from the red child to the green child. This is strange physical behavior since the surface is flush.

This probably is not unique to children of compound shapes, but I did not test that.

Possible explanation:

What I'm thinking, is that this happens because there is a penetration depth that makes the corner of the yellow box sit below the surface of and because of this the corner catches the vertical plane of green child.

Question:

Is my explanation correct?

If not, what do you think causes this behavior?

Is there a way to prevent this behavior? I know the split-up in convex sub shapes could be done different to avoid, but in my case this is difficult if to avoid.

Many thanks!