When reverse engineering a part or designing a new one I plot my layout on copier transparency film to double check my idea. Not all printers will print on the completely clear film so double check your printer specs.
After doing the drawing in cad I print on the film. My HP LaserJet works great for this.
An example of this use is this layout of a part that I may want to mount on one of my fixture plates. After awhile these plates look like swiss cheese with all the holes. This method gives a quick visual of where I can mount the part and what if any original holes can be used. For me it is a handy tool.
