Proper way to offset CollisionShapes

Troubleshooting physics
1

Hello. So I’ve noticed that CollisionShapes in the engine are centered at the origin. Should our models be as well? So this doesn’t happen:

Or should we just offset the CollisionShapes? If so what is the best way to do this? I’ve seen a method that uses CompoundCollisionShape but I don’t know how I feel about that.

2

Yes, I think that’s right. Or stick them under a node to center them and let the collision shape go with the node.

…but on some level collision shapes will always be based on the center of gravity.

3

The performance hit for adding them into another node is negligible right? There is more matrix multiplication involved?

4

Almost nothing.

5

I decided to add an optional vec3 Offset to CollisionShape. That gets applied to the PositionComponent after physics update like this:

PositionComponent p = e.get(PositionComponent.class);
CollisionShapeComponent c = e.get(CollisionShapeComponent.class);
rigidBody.getPhysicsRotation(p.getRotation());
rigidBody.getPhysicsLocation(p.getPosition()).subtractLocal(p.getRotation().mult(c.getOffset()));

Felt better than adding to a node to center.