Let’s say I have uneven mesh of which I’d like to capture only outer edges. I usually extrude all faces of the mesh, deleting the extrusion and using the rest to capture original’s edges by the proximity of said extrusion.
But I think this is unnecessarily demanding operation, if done on complex models. Would you think of a better way?
Select edges.blend (1.2 MB)
You can check for the number of edge or face connects.
Maybe have look here ( …since it’s the manifold edges ?):
I can’t, mesh in my case can be pretty random.
Thanks for good read, but after trying it on my unpredictable mesh, it’s not reliable (unlike my boolean method so far).
Arrggghh… too bad there is no select manifold option in geometry nodes… yet 
.
( And TBH i haven’t looked very deep in your example… i also overlooked the blend file 
)
Thanks, this seems to do exactly what I wanted even on less then ideal topology and performance has reduced to 1/4 of my original extrusion method! 
That’s “funny”(…or better awesome) how an oh-i-saw-something-like-this-and-have-a-look-here–post leads to some “crossposting” and finaly results into a solution…
It does keep the verts from where the deleted geometry joined the outer edges, but then so does the original solution. I thought something like this yesterday, but filanek beat me to posting it because I went down a rabbit hole failing to solve the extra vert issue as well. 
I’m sure there is a way round this and I’m just missing it, but it would probably increase performance time again anyway, and depending on your needs the additional verts might not matter.
Possibly a question to revisit if there are a lot of these types of objects and the scene gets really heavy, as the extra operation’s performance might become comparatively less of an issue vs the extra geometry (I’d probably try dropping the resolution of the profile curve at the end though, unless it really needs to be 32).
