Where is the tool preview being drawn (source coud

Hello.

It would be helpfully if someone could get me in the right direction. Where in the source code, the tool preview is being drawn (in the toolpath preview - also known as backplot, present in axis for example). I have looked in axis.py and gremlin.py, but I am not sure.
As it is a known bug - if a user uses the backtool post in the lathe mode - the tool preview stops working, and I would like to adventure in the source code looking for the issue.
Further tests shows that this only happens with tools with a diameter defined (for diameter = 0 the tool preview is present).

Thank you.