whats faster a raycast, or a collision test

ive heard that excessive raycasting will take a chunk out of performance, i need 30 things in my scene to be raycasting every frame, but i also thought of a way of doing it using an empty GO with a box collider


which is faster?

 

Probably the box collider. What else is in your scene?

 

its a generic shooter, the 30 objects are little bombs on a flocking script im working on that track the walls and ground and move towards a target being selected by the player