I started watching this and couldn't stop. It is ridiculously impressive. I would guess he would have used some CAD tool to design this excavator? It had to

I started watching this and couldn't stop. It is ridiculously impressive. I would guess he would have used some CAD tool to design this excavator? It had to have been very carefully thought out to ensure proper access to put the pieces together and take them back apart all along the way. Does he say in other videos what he uses?