Rotation Friction


Does friction not work on rotating objects or do we need to do something more complex than I am aware of?
I can see that the Vehicle Demo works fine (and I imagine the wheels are taking friction in consideration to rotate, but it appears to be a custom module for the vehicle).

A simple example:

The above image has some rotating Round-Blocks - They appear like they rotate alright (and the collision geometry seems to do so too). I set the friction on both board and blocks via Physics Material (and upon testing on a slope they seem to be working as expected).

But if I let the board fall on these rotating blocks, the board does not move at all. Am I missing anything?

Are your rotating objects set as colliders or as rigid bodies? If they aren’t rigid bodies, they will need to be to have a velocity. Have you set the “kinematic” flag on the rigid bodies?

It is quite likely that the issue is that these rotating blocks are probably just having their transforms set rather than being rotated via a velocity. If there is no velocity being applied to the rigid body, then friction won’t cause the board to move because all the physics engine sees is that the transforms are being set each frame.

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That was totally it :)

Thanks for the input and for the explanation too! That makes total sense.

Great. Glad that solved it for you

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