How to identify brep edges where brep is G1 continuous

Does somebody have a good idea how I can identify those edges of a brep where there is no "kink" in the brep, i.e. edges where the brep is at least G1 continuous?

The background is: I would likle to write a meshing component, and the mesh vertices close to the edges should snap to the edges. With the exception of edges where the brep is G1 continuous. In these cases it would look strange to have a "seam" in the mesh.

In the case of a truncated cone, the "verticalish" edge would be such a case:

Replies to This Discussion

Permalink Reply by Arend on November 12, 2014 at 5:14am

This doesn't use continuity, but you could use the IsSmoothManifoldEdge on the BrepEdge object?

private void RunScript(Brep x, ref object Smooth, ref object NotSmooth)
{
    List<Curve> output = new List<Curve>();
    List<Curve> output2 = new List<Curve>();
    foreach (BrepEdge be in x.Edges)
    {
      if (be.IsSmoothManifoldEdge(RhinoDocument.ModelAngleToleranceRadians))
      {
        output.Add(be.DuplicateCurve());
      } else {
        output2.Add(be.DuplicateCurve());
      }
    }
    Smooth = output;
    NotSmooth = output2;

}

Permalink Reply by Stefan on November 12, 2014 at 6:16am

Thanks! That sounds good.

I'll try it.

Permalink Reply by David Rutten on November 12, 2014 at 5:24am

The continuity of two adjacent faces on opposite sides of an edge may differ from place to place, so do you want to only find edges that are entirely continuous or do you want to find -for every edge- the domains over which the adjacent faces are continuous?

Permalink Reply by Stefan on November 12, 2014 at 6:15am

I suspected that :)

It would be best to have the domains of edges where the faces are continuous.

Or, more to the point: what I am actually interested in are those edges (or parts of them) where the faces are non-continous. I just asked the question the other way round, because that seemed more intuitive - for some reason.

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