so is it really just a matter of tracing the line visually with the mouse? I'm not sure my coordination is that good. could I just tell the computer "trace ridge" or "trace couloir" in geekspeak and have it done without error?
you don't even have to use a fancy art program if you have powerpoint for making presentations. You can insert the .jpg of the photo, draw on top of it with a simple line tool, group them all together and save it back to .jpg