fill a bottle with pills mesh collider

3D Game. I have four pills and put in a bottle. I added mesh collider to bottle. Pills can not enter outside of bottle but when ı put in bottle , pills can exit from inside of bottle. Is this a bug ? or how can I fix it?

 

If the bottle has a rigidbody it’s considered dynamic. This makes the mesh collider calculate the convex hull of the bottle and makes it a solid, filled object. Remove the rigidbody from the bottle and try again. If it works now that’s the culprit

 

Your mesh may not contain back faces. If so, this is something you would need to fix in modeling software, not Unity.