how to determine rigidbody3d heights?

Godot Version

4.2.2

Question

hello! i am having trouble trying to determine the heights of rigidbody3Ds.

the goal is that a visual prompt will appear half of an objects height above it.
my issue is that there are imported assets with varying sizes and origin points.
is there is a property within the rigidbody3D scope i can access to easily determine the height value to then apply my prompt function?
so far i have had no luck using global_position.y :confused:

i hope this all made sense and thank you in advance for any help!