Shifter Boss?

Hi. I'm new here. Mainly interested in designing a couple of components rather than a whole bike or frameset. Are there design files that have a standard downtube shifter boss in them? (with the actual rounded rectangle shape) I am trying to design a shifter mount to be 3D printed (sintered) from aluminum. Trying to come up with something similar to the old WTB Multimount shifter adaptors but made to adapt downtube shifters instead of thumbshifters like the originals were made for.