Trying to create a spawn box in godot 4.2

Godot Version

4.2

Question

I am trying to create a spawn box using a meshinstance3d cube as a visual guide. But I could not figure out how to get the size. I trying to place object in random locations within the cube area.

Any thoughts on how to fix this or and alternative.
thanks,
True

A slightly different way of spawning an object in a certain area is with code. Say you wanted to spawn the object in a random spot in a 10x10x10 region of a point.

var rng = RandomNumberGenerator.new()
var point = $Path_to_Point
var object = $Path_to_object
func randomSpawn():
	object.global_transform.origin.x = point.global_transform.origin.x + rng.randf_range(-10.0, 10.0)
    object.global_transform.origin.y = point.global_transform.origin.y + rng.randf_range(-10.0, 10.0)
    object.global_transform.origin.z = point.global_transform.origin.z + rng.randf_range(-10.0, 10.0)

Thank you