How To UnTrim the hole on the Brep

Replies to This Discussion

Permalink Reply by David Rutten on July 5, 2017 at 1:01am

There's an Untrim component, but it untrims everything, it doesn't know how to distinguish between the holes and the boundary. Is that a problem?

Permalink Reply by cughudson on July 5, 2017 at 1:26am

Thank You,David. As you know, Untrim component is not a good way to repair the surface with hole,It untrims everything.  the command "UntrimHoles"(It is not 'UntrimAllHoles', I'm so sorry) in the rhino can help to repair the hole,when I bake the facade geometry to Rhino. But If I Know using C# code to relaize the command "UntrimHoles",  I can repair the facade with holes. Could give me some suggest about how to realize the command? 

Permalink Reply by cughudson on July 5, 2017 at 11:50pm

I can  not find an usualfully way to distinguish the holes and the boundary.yestday,I think use the boundary's length to test whether it is an holes or an boundary. but it is an alway right.

Permalink Reply by David Rutten on July 6, 2017 at 4:35am

The BrepFace class knows which one of it's potentially many loops represents the outer boundary. But I can't find a way to actually use this information to then remove the remaining loops from the face interior.

You may have to ask the Rhino api experts on the discourse forum about how to do this.

Permalink Reply by michael sprinzl on July 5, 2017 at 1:33am

You still need some maunal work around but thsi should help.

public static Brep BrepUntrim(Brep brep)
        {
          List<Brep> b = new List<Brep>();
           var f = brep.Faces.ToList();
            f.ForEach(x =>
            {
                var l = x.Loops.ToList();
                l = l.Where(y => y.LoopType != BrepLoopType.Inner).ToList();
                var tb = x.UnderlyingSurface().ToBrep();
                tb = tb.Faces[0].Split(l.ConvertAll(z => z.To3dCurve()), 0.001);
                tb = tb.Faces.ToList().ConvertAll(z => z.DuplicateFace(true)).OrderBy(z => z.GetArea()).Last();
                b.Add(tb);

            });

            var untrim = Brep.JoinBreps(b, 0.001).ToList().OrderBy(x => x.GetArea()).Last();
          return  untrim;
        }

Permalink Reply by michael sprinzl on July 5, 2017 at 1:50am

You could filter the Faces from the generated Brep a second time for the inner outer loop criteria. I leave you some home work.

Permalink Reply by michael sprinzl on July 5, 2017 at 1:47am

Permalink Reply by cughudson on July 5, 2017 at 2:21am

Hi I'm have test it in my Grasshopper using C# component(there has something error in the code), But the result is the same as using Untrim Component. the result is attached at below