I use the Edge Surface component for generating a surface from three arcs. The result is unfortunately a Brep which has 7 surfaces but only 4 faces. This does not happen if I bake the arcs and generate the surface directly in Rhino.
Surfaces with surface index 3-6 correspond to the brep faces. Surface 0 is the whole surface with C0-continuities. Surface 1&2 are parts of it (see image). So there are kind of 3 valid results but only one is used for the brep.
Yes, but the problem is that the outcome is a brep which basically contains 3 versions of a valid solution (at least when using the component).
I access the Brep.Surfaces in my program, so I get “duplicated” entities.
Not necessarily. You should always run SplitKinkyFaces after to cover cases using kinked edges, otherwise you will have creases which don’t usually play nice elseware. Rhino also does this (baking into rhino will also run split kinky as well). Unless you explicitly turn off crease splitting in Rhino which isn’t really advised.
Probably, I just have to check if the Brep.Faces.Count == Brep.Surfaces.Count to avoid such bugs in the general case. If not, I can just access the Surfaces by using Face[i].UnderlyingSurface() in order to avoid having three times the “same” geometry in my model/code. The face list is hopefully unique.
It does? I use it in the C#component in the file which I originally posted. I am sorry but I don’t understand.
The problem is that my whole code refers to brep.surfaces list in a brep geometry but apparently it is possible to generate breps which do not have consistent lists. So either I check for consistence or I access the surface with Face.UnderlyingSurface in the whole code. I am also wondering if the face list is then always unique or if similar problems can also happen there.
Why not remove the unused Surfaces in the surface list then? In your example three of the surfaces are unused, so no face refers to them, once you clean up the brep, those also get removed and everything is consistent? Maybe a question for @dale or @DavidRutten, but I doubt that one face can actually refer to more than one surface?