@unknownuser said: This Bounding Box includes rotation, so X, Y , Z sizes are not object sizes. Is there a way to get exact sizes of objects (or groups,entities.. any kind of selection)according to local ("objects") or world coordinate system? (Sorry if my terminology is wrong). Here is my solution: b = instance.definition.bounds t = instance.transformation x = ((b.max.x-b.min.x) * t.xscale) y = ((b.max.y-b.min.y) * t.yscale) z = ((b.max.z-b.min.z) * t.zscale) Hope it helps Have fun!