Hey @datamilch,
Thank you for reaching out to us. GetRad and GetMp express the locally aligned bounding box of an object. I.e., the bounding box in the coordinate system of the object. For a world space aligned bounding box we once had this thread, the Cinema API does not offer this out of the box.
So, transforming an object will never change its bounding box. What will change the bounding box of an object, is changing its size or changing the parameters of a generator object. When you change the parameters of a generator or when your instantiate a new object, you will have to execute the passes (BaseDocument.ExecutePasses) on a document that contains the object to see the correct bounding box - or wait for the next scene update.
PS: Your script is also running illegal code. You cannot modify the active document off-main-thread. I assume the is a script for a Python generator object. Its main function runs off-main-thread and you call there your csto which in turn calls SendModelingCommand on the active document. This will all sooner or later crash.
https://developers.maxon.net/docs/py/2025_3_1/manuals/manual_threading.html#threading-information
Cheers,
Ferdinand