Just wanted to share this : Brecht added support for geodesic distance calculation across a mesh’s surface -not only lifting the limitations induced by the old naive technique, but also potentially opening up different uses notably for diffusion effects in simulation nodes. It’s also going to improve sculpt mode a whole lot, by making the brush falloff depending on the surface flow rather than naively grabbing what’s within the brush radius. Pablo (Dobarro) has expressed interest in using it in some way, at least. Let’s see !
I had logged a bug report years ago concerning this issue and I’m incredibly thankful he worked on it. It’s one of those ancient Blender limitations we won’t have to deal with again.