In 3D physics materials, we have the setting "Bounce Combine" which decides how the two phys materials in the collision combine to determine the overall bounce of the collision. The choices are Average (of the two bounciness values), Minimum, Maximum, and Multiply which just multiplies the bounciness values together Multiply is the mode I really want, but this setting of 'Bounce Combine' is not available for 2D Physics materials, and the way it works by default is the equivalent of 'Maximum'. In a previous engine I used, I could edit a single line in box2d directly, but as far as i know, this is off limits in unity, so I feel like i'd have to recreate my own bounce code using OnCollisionEnter2d collision contacts, and reduce all physics materials bounciness to 0 Does anyone have any other ideas? Or how to go about making this code? Getting circles to bounce correctly off flat kinematic objects seems okay, but when it's boxes and other shapes, and they're bouncing against other moving things, I have no idea how to code for that. Another approach could be to set bounciness of all phys materials to 1 and instead reduce the velocity according to my own bounciness value, but i don't know if this is any easier. I'd appreciate any input, thanks!