Unity Game Optimization - Third Edition

Optimizing the Collision Matrix

As we know, the physics engine's Collision Matrix defines which objects assigned to specific Layers are allowed to collide with objects assigned to other Layers. To put it more succinctly, which object collision pairs are even considered viable by the physics engine. Every other object-Layer pair is simply ignored by the physics engine, which makes this an important avenue for minimizing physics engine workload since it reduces the number of bounding volume checks that must be performed every fixed update and how many collisions would ever need to be processed during the life cycle of the application (which would save on battery life for a mobile device).

Note that the Collision Matrix can be accessed through ...