This is a simple tool that is 5/8" wide at the base. It can be used for drawing in seams from standard US seam allowances by pulling it along the cut edge and drawing in the seam with disappearing ink or tailors chalk. Chalk may not be able to get super close to the bottom edge of the tool. In that case, you might want to chamfer off a little bit of the print.

It can be sliced with no supports.