How can I change the collision channel of a specific physics body so that projectiles don’t hit self?
It’s not a hit event, it’s a literal collision.
I want to disable only the collision detection with bullets while maintaining other collisions.
You can set your bullets’s collision settings to ignore collisions for physics body. Or you can create a new collision channel for your bullets / character’s physics to ignore specific objects.
Here’s a documentation 
Sorry, I’ve seen this method many times.
But honesty, generating thousands of collision patterns for each object and faction just to avoid colliding with itself is exessive.
If you already have 10 channels, adding one will add 331 collide patterns.
Most of it goes unused, but the amount of work grows exponentially as i add more objects.
So I would like to know how to disable collision for only a single body.