See animation below:

Red ball passes through everything.

Blue ball passes through both stairs and green plane but finally collides with blue plane.

I have been trying to fix this problem for 4 hours now.

Blender file:

Animation: Planes physics


  • Blue plane, green plane and stairs all have the same physics with just the collision on (no settings changed): Planes physics

  • Blue ball and red ball have the same physics, collision and soft body turned on:Balls physics


I think you need to simplify the physics models. Here is what I have for the blue ball and then the stairs:

enter image description here

enter image description here

I didn't change any of the soft body parameters, using the defaults instead. I did set the stairs to Passive and made sure the blue ball was active.

Since I didn't tune the rigid body parameters, the balls tend to pass part way through the stairs, but they do bounce and roll down the stairs.


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