automatic creation of BoxShape3D around mesh

[timothy]

Godot Version

4.4.1

Question

Is there are way to specify a BoxShape3D as the collision object for a mesh, and have it set automatically to fit the mesh like a bounding box? I can manually pull the bounds around in the editor, but I’d rather it was lined up perfectly and quickly.

[dragonforge-dev]

You can set one on import and calculate it in an import script.

[mrcdk]

You can get the bounding box (AABB) from a Mesh with Mesh.get_aabb()

[timothy]

@mrcdk that works the aabb uses a start position while the boxshape uses the center of the node, but with a small calculation it works fine. Here is a function that does it for static bodies.

## creates a minimal static BoxShape3D collision shape around the given mesh
## and attaches it to the given Node3D.
static func add_box_collider( node:Node3D, mesh:Mesh )->void:
	var coll_obj:CollisionObject3D = StaticBody3D.new()
	var coll_shape = CollisionShape3D.new()
	var box = BoxShape3D.new()
	
	var aabb:AABB = mesh.get_aabb()
	var center:Vector3 = aabb.position + aabb.size/2
	coll_obj.position = center
	box.size = aabb.size
	
	coll_shape.shape = box
	coll_obj.add_child( coll_shape )
	node.add_child( coll_obj )