how to i save G code in CB for a 3d object
You right click in the graphics area, then in the flyout select "Produce gcode" and save it to a place of your choice, then
load / run the file in Mach.
if CB is not that good for 3d
I didn't say that, I only mentioned some limitations, only you can decide, and you need to walk some before you run.
would be best 3D cam program
All depends on how you will do work, how much money you want to spend, if you like the software interface, time you may may
need to learn the software. So there is a lot of "you" in determining selection and what is fine for me you may hate.
RICH