Hi all,
Does anyone know if there’s anything in rhinocommon or the c++ SDK underneath or compatible third party libraries that have these sorts of algorithms in?
Equivalent methods for some(but not all) of those exist in RhinoCommon.
I think most of the intersection and distance stuff on that list would be possible. For the graph/Delaunay/convex hull stuff you’d need to reference another library.
It might be more helpful to ask about the specific functions you need to use.
Also - this is a screenshot of David Eberly’s Geometric Tools site - what about actually using that library? It has a fairly permissive license.
https://www.geometrictools.com/index.html
Well I’m trying to keep it C# and didn’t fancy wrapping his C++ libs. Laziness and time is why, basically. 
Daniel, is there enough in rhinocommon to enable me to implement a minimal bounding box using the rotating calipers algorithm ?
It depends on how skilled you are in filling in the missing parts. People have done, and are doing serious attempts in different languages:
https://discourse.mcneel.com/search?q=minimal%20bounding%20box
// Rolf
Oh I see. It’s been done to death already. Clearly, I should use search facility more often.