I’ve seen this happen on a few random occasions under different operational circumstances. This time it was after a fillet of a long edge. A resulting surface appears in the render, but it has no apparent edges - (under close inspection it does indeed have a single super microscopic single edge way down near the molecular scale).
In any case, it seems pretty random (I do have some sense of the feature that likely catalyzed it) - was deep in the midst of heavy modeling and didn’t closely track the conditions around its manifestation so I don’t know how repeatable these things are. But I thought I’d share here in case it’s useful and/or anyone in McNeel or the general community has any insights.
A subsequent filleting attempt was successful - so I moved on, but remained curious if people have any awareness of ways to repair, or otherwise interrogate these kinds of objects.
I just ran through my undo history and wasn’t able to locate the stage where this generated. (It’s also a client project - so unfortunately can’t readily show the larger context).
What I am guessing may have been involved was there was a tiny edge segment that possibly didn’t get selected when the fillet was made. There was a little “hanging chad” in that area that I later resolved, and when it popped up I immediately worked around it (can’t recall how specifically, possibly by temporarily shifting tolerances)
Is your observation that the object has an error based on info in this description window?
Reflecting on this a second I realize my main motivation for posting this is to ask if anyone can shed some light on the deeper structural aspects of this general phenomena.
I have this mental model - (probably incomplete) where surfaces are derived from (and are fully dependent) on their edge curves. Mainly coming from the curves-in → surfaces-out workflow extolled by Sky and other surfacing experts here.
This conceptualization is based on only a few years of working with Rhino/NURBS, (and spending time in the documentation and watching lots of surfacing tutorials) - and also with a longer background with various 2D CAD environments, like AutoCad, Illustrator and various ECAD Gerber environments - generally there is a (somewhat) discernible “deep structure” lurking closer to the metal of the software - in the case of Illustrator, from the Postscript format everything is a bezier + fill, in Gerbers it’s a line/arc and an aperture for a photoplotter.
So it’s just super interesting (suggesting some other as-yet imagined layer of existence) how this object is possible having surfaces without edges . . .
From what I can see its a trimmed surface. Very often the trim curve can be the problem. The surface obviously looks ok. I think usual suspects are adjacent surfaces with problematic boundaries or surface properties. Sometimes if you trim with positional mismatch or projection-based this can cause the issue. Therefore it would be useful to see the surfaces and trim curves next to the surface
