Had to interface to a 2x8 IDC connector on a ribbon cable; printed this to help keep the individual DuPont connectors in place; worked surprisingly well.
Haven't printed the long version yet, but the idea was for the pins to seat against the edge at the bottom, so need to insert them from the front.
Side edges have a 2 degree draft to facilitate easy insertion and snug fit. Mate all the male pins into the female IDC and use it to guide all wires into adapter. (or buy 2x8 DuPont housing)
Edit: needed some 2x3 and 2x5 for other stuff and just added it here. included step files if anyone wanna shift around to make different sizes, its all 0.1" grid
Edit2: someone needed it panel mounted..