LOL before I built my CNC I had NEVER touched a CAD program
The way I work while it may not be the correct way I get the results I want/need and Inv8 suits this.
I tried AutoCad and found it far too structured and that they assume you actually have a clue!
I rarely render or make full models these days as I can visualise what the part will look like in my head and from the DXF, without some way to make the part reality it's just pretty pictures.
I almost never make 3D parts as the code ends up HUGE and slow and prefer 2.5d (2d with a Z measurement for depth)