Brian, I import a scanned tiff image into Autocad and draw/trace the required outlines, if its a plan, trace the existing formers, print them and then cut them out.
I use my laser cutter for this.

Any CAD program can do this, Draftsight is a free one that works like Autocad.

Here's an example.

hope this helps.

For 3D look at this thread.
http://www.rcscalebuilder.com/forum/...TID=13603&PN=1

Bob