I have once used Unity to visualize a machine my husband build in virtual reality. Mostly the 3D CAD for mechanical engineering and 3D design tools for games are different worlds. Kind of like vector graphics and bitmaps in 2D. We had to find a way to convert the data format first and the resulting 3D models had millions of vertices - something that is almost criminal in game design. We had to buy a computer good enough to handle that. Nevertheless the result was impressive - you could kind of walk into the operating machine.