I am using 123D Design to build a model for 3D printing. What I want to build is a large 2D rectangle with several smaller rectangles inside. Then, I want to extrude the larger rectangle, but leave the smaller ones as holes.
I thought that I could subtract the smaller rectangles from the larger one and then extrude the remainder. However, when I use the subtract tool, I cannot select sketches - just solids.
Any ideas on how to do this? I would very much like to know how to do it 2D first, and then extrude the remainder. However, if I must transform this to 3D first, I'll be willing to learn that instead. Much appreciated!