I recently made some artificial trees for a theatre production, Yarla and the Winter Wood for Edinburgh baby-theatre company, Starcatchers. The bases of these were CNC routed on our 8' x 4' bed from 12mm plywood. Here is how I went about generating the drawings for that.
First there were a few iterations prototyped by hand, using pencil and paper, and some 20mm blockboard that I had leftover in my studio. Because the trees are designed to tilt during the performance, the bases required a little bit of mechanical engineering.
When I was happy with the design, I transferred to Solidworks, a solid modelling program. In that I drew out each part to be routed and put together an assembly to test that the geometry fitted, and that the tilting would behave as desired. I then used the drawings module of Solidworks to generate 2D drawings from projections of the 3D parts. I then exported a .dxf file from Solidworks into Illustrator for checking and nesting the required number of parts into the outlines of the 3no. 8' x 4' sheets that I would be using.