It always amazes me what gets left out of AutoCAD.
Like we have materials, but we don't have densities.
490 pcf for steel for example.
Sometimes it is good to know how much something weighs... right?
Attached you will find a lisp routine called "centroid" and a sample drawing called centroidtest.
If any of you are interested, could you CRASH test it for me?
You can add densities to material objects in the materials table.
If you select items (blocks or solids) it will find the total weight and the centroid.
P=
PS.. Found a minor bug, and re-uploaded the zip file.