Undesired friction when multiple objects are colliding with a rigidbody.

Questions & Answers
1

In my project I have a rigidbody cube inside of a hollow box that falls in a straight line down along the y-axis (all rotation and movement except y-axis motion is restriction). When the cube is only touching one wall of the cube, it falls as if there is no friction between the container and the cube (this is the desired result). However, if the cube is falling along an edge of the containing cube (touching two walls of the containing cube) it falls slower as if there is friction. If it begins falling from the corner of the containing cube (touching three sides of the inside of the containing cube) it falls extremely slowly. Each wall of the containing cube is a separate object modeled in bender and imported with colliders and scale set to 1. I have set the physics material for all objects to a frictionlessMaterial which has all values set to 0 and minimum.

tl;dr How to I get an absolutely frictionless environment for my cube to slide happily around in?

2

I have run into this problem as well when trying to build a rigid body character controller. I fixed it by making all the objects ridged bodies. For some reason rigid bodies interact strangely with non rigid bodies in this particular way. It may be a bug with the physics engine IDK. Any way, add rigid bodies to your walls and restrict all motion and check Kinematic and you should be good.