I use Solidworks to design my bots, but any CAD program would be fine for such 2D parts. I then save the drawings as PDF, and print from there... Usually there's an option in the printing dialog to the effect of "do no scale". And of course I always take a measurement or two to make sure...
One other note is that this method works a bit better for carbon fiber where the debris (which you absolutely don't want to breathe) is small. With plastic, the debris can bunch up under the paper, but it really wasn't a problem...