So I have two gamobjects with colliders, in this case an ammo box and a player, and I want the player to collide with the ammo box, i.e. they have to walk over it rather than through it, and I want the ammo box to still have physics and collide with the floor, but I don’t want it to collide with the player, i.e. the player knock it over. As far as I can tell, with the collision matrix and things like Physics.IgnoreCollision you can only make it ignore collision both ways, rather than just one. Does anybody have any idea if this is even something that can be done in unity?
Collisions are not directional. When two colliders collide, it’s a single contact of the pair. Just because one moved causing a contact doesn’t make that a direction. In a lot of cases two can move.
You can use a collider for the collision with the ground and another collider (set as a trigger) on a child GameObject that is set to contact the player (presumably for collection).