Ooooo now that is a rabbit hole! I know! But totaly worth it! You see a design you like, setup the plans, cut out the foam on the cnc, cut out the plywood on a cnc, 3d print a few parts, and boom you have a kit! Then you get an idea and want to change the design, go through the same steps and boom you have a custom kit! I find building the cnc machine, building the tools, ect to be more fun then the planes!