When i apply rigid body modifier after punching a hole in a cube for inserting a rotatable propeller so that it rotates only when something collides with it.

But when i run the simulation the propeller shaft pops out of the hole and the cube behaves like it had no hole in it, even after after selecting "mesh" for the shape of physics body.

the cube with hole


1 Answer 1


By default the shape of rigid body collisions is set to 'Convex Hull', if you want the the collision shapes to include holes you need to set the collision shape to 'Mesh':

enter image description here

However like it is indicated in the comments, if you need objects constrained to each other you should use Rigid Body Constraints, otherwise you might not be able to get a smooth simulation without errors.

  • $\begingroup$ You are correct. I missed that. It seems I cannot replicate the issue then. However if Convex Hull is selected as Collision shape everything matches the description of the problem perfectly. Maybe double checking that the correct objects have this setting is not a bad idea. $\endgroup$ Commented Sep 20, 2018 at 14:15
  • $\begingroup$ Missed it too at first: removed initial comment that suggested same. Agreed, does pay to double check. $\endgroup$
    – batFINGER
    Commented Sep 20, 2018 at 15:10
  • $\begingroup$ i had selected mesh for rigid body shape i know that it is set by default as a convex hull. $\endgroup$
    – A-K
    Commented Sep 21, 2018 at 5:50
  • $\begingroup$ Please share a .blend file then. It works as intended no matter what I do trying to recreate the issue. $\endgroup$ Commented Sep 21, 2018 at 5:57
  • $\begingroup$ Problem solved when i scaled up everything . $\endgroup$
    – A-K
    Commented Sep 22, 2018 at 10:13

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