Often, I want certain GameObjects, which I’ll hereafter refer to as “entities”, to exhibit the following properties: I want entities to use Unity’s physics system for collision with terrain, but to pass through fellow entities (So enemies and the player, which would be entities, can stand on the ground but not on each other, etc.) However, I still want scripts I write to be able to detect when entities overlap (So enemies can turn around when they walk into each other, etc.).

I started developing with unity a few days ago.