Naked edges while extruding

Can someone explain to me once and for all why I end up with naked edges when extruding/trimming?

I use the Osnap and it should be sealed, no? On this model I have tried to close off the hinches but ending up with naked edges. If this is not the way to close things like that, what is the right way?

MNakedEdges.3dm (277.8 KB)

I would say that there is no right way for a situation like that. Why do you feel you should close that surface there. It will only lead to non-manifold edges - places where more than 2 surfaces join on the same edge. That is not a situation that one would aim for.


Not sure exactly what you mean… the one on the left looks good.
One on the right had problems since one of the surface was not trimmed before joining
(but, it seems you got it done in the left one…)

If you mean naked edge on the left polysurface, it’s a naked edge since it’s not closed.
Once you mirror in y&x-axis and join it all up you’ve got a good closed polysurface.

Basically I want to learn how to do this the right way, if I for instance want to print this model out and manufacture it, id think those wrist band hinches had to be closed of and not hollow. But, I am a beginner and just want to learn more. So that is the reason I wanted to close them off because they are supposed to be a solid peace

If you look inside the right one, you ll see that it s closed off, as oppose to the left one. And when i add that extrusion i end up with a naked edge

What most 3d printers need is an unambiguous closed outer shell.

The printer needs to know what is inside the part and what is outside the part so that it only deposits material where it thinks it is “inside”.
If there are holes or breaks in the outer shell then it gets lost figuring out what is “inside” and what is “outside”

I see.

Way to think of it is when it’s closed at the end, it’s all good.
You don’t need to think too much about having closed parts while editing to have a valid solid to print out. Unless, the parts are a separate piece. (In this case not)

The naked edge in your sample is coming from only parts of edges of a surface connecting to parts of edges of a surface. Polysurface looks connected, but it’s just held together only by few edges.
If you use extractsrf, to extract the hinge part one piece at a time, you’ll can see that
naked edge is partially there in the main watch part.
If you explode then join the main part again, it’ll remove the naked edges.
So when you joined the first time rhino tried to join everything as much as possible.

NakedEdges_extract.3dm (303.0 KB)