The result is a 3D model that is like a solder paste mask combined with a raised border to match the board outline, so that the whole thing self-aligns by fitting on top of the PCB. A handy ...

To make this task a little easier, [Max Scheffler] built the Stencil Fix Portable, a compact self-contained vacuum table to hold your stencil firmly in place and pop it off cleanly every time.