[b]Note:[/b] Even with [member bounce] set to [code]1.0[/code], some energy will be lost over time due to linear and angular damping. To have a [PhysicsBody3D] that preserves all its energy over time, set [member bounce] to [code]1.0[/code], the body's linear damp mode to [b]Replace[/b] (if applicable), its linear damp to [code]0.0[/code], its angular damp mode to [b]Replace[/b] (if applicable), and its angular damp to [code]0.0[/code].
If [code]true[/code], the physics engine will use the friction of the object marked as "rough" when two objects collide. If [code]false[/code], the physics engine will use the lowest friction of all colliding objects instead. If [code]true[/code] for both colliding objects, the physics engine will use the highest friction.