Parametric Face-Up Keyhole Generator

Sometimes you need to print a model face-down for details, but you still want to have a keyhole to hang it from. The standard keyhole shape works great when printed downward, but leaves some sharp overhangs that never print well. I wanted to make this easier. What I've drawn up here is a parametric shape that you can combine with an existing object as a negative to add a keyhole wherever you want it in your models. The intent is to have an internal geometry that creates easy-to-print bridges by staggering the layers a little, giving you only a few short, straight overhangs instead of free-floating curves and points. PARAMETERSThere are three variables to control:“Head Width” is the diameter of the widest part of your nail / screw / thumbtack / hook / whatever. There's a 1mm tolerance added to whatever number you put in.“Hole Depth” is the total void space created. You can probably go quite thin for most nails, but some screws and for sure thumb tacks will require deeper holes.