"Disconnected" Input for the Cycles Geometry Node
This input should detect and shade disconnected edges by using temporary vertex colours (as the pointiness input does). Useful for pointiness-like shading on specific areas, and easy to generate by just splitting edges. Should work perfectly with the Edge Split Modifier.
Very usable for creating quick procedural dirt in areas where pointiness fails, ore gives imprecise results, but there are endless possibilities of use, such as frost effects on windows and so on. If there was a way to generate open edges with the Boolean Modifier (I'm working on a proposal about this) you can create animated sea shore effects with it.
If it's easier (in terms of programming) to detect non manifold geometry instead of disconnected, this should work as well.
4 Comments
How would you define "disconnected"? My guess would be "only one face touches the edge"? Also, the problem with edge-specific data is how to interpolate it (same as for my edge length patch) - per-vertex stuff is easy, but for example, consider a half-icosphere. It will have some tris that have a vertex at the disconnected seam, but all three edges are perfectly connected...
"Non-Manifold" is already defined in Edit Mode, I'm guessing that's what they meant.
What are the use case?
Of course, I really should get more precise. Edited the description, thank you mentioned it.