So, I wrapped up PR#12931 on handling implicit intersections. I’ve to clean it up a bit more as suggested by Christopher. I plan to implement the Bentley-Ottmann Algorithm and the case with intersecting polygons with more than two sides passing through same point in separate PRs.
Now, about the 3D case I initially thought about writing a 3-Polytope class first but I now realise that there is no need as such. The API can be kept simpler. I’ll update this post with a PR link for the 3D case quite soon.