In most decent Cad packages you can load a good quality picture, taken from directly above against a plain back ground that contrasts with the part ie: black on white and accurately measure the length and height of the part then load it into Cad as back ground then trace it and scale it to size. Some will even do the tracing for you.

You can then print it at 1:1 and test against your pattern part, if it's correct send them the file or make any alterations needed.

If you haven't got Cad and can't do this then take the Pic like mentioned above with measurments and I'll do it for you.