Wondering how best to generate geometry at the edge of two intersecting solids.

[david.chinikaylo]

I'm trying to create an personal addin to generate edge joinery for cnc, the link below is for Dovetail-Pro addin by WOOSOUL and works pretty much how I'd like mine to work with selecting two solids that are intersecting and the joinery is generated at the intersection ends.

https://apps.autodesk.com/FUSION/en/Detail/Index?id=8070538905110298047&appLang=en&os=Win64

I guess I'm wondering how best to generate the joinery geometry at the intersecting ends? The solution I've come up with involves a lot of point math and comparisons that feels very cumbersome and like im doing it the wrong way. 

any guidance is much appreciated thanks.