Splitting a Brep by a curve (rhinocommon)

Rhino Developer
1

A have a brep that consists of an untrimmed surface and I want to split it by a curve. The split function can split a brep by another brep, but what about if I want to split a brep by a curve?
I’m suspecting I might be confused here… can a brep consist of just a curve? Figuring this might be the case, I tried TryConvertBrep on my curve and then used the resulting brep to try to split my original brep, but that didn’t seem to work for me. Any suggestions?

Thanks,
Sam

2

If your BRep consists of one untrimmed surface you can do this:

Brep b;
Curve splitCurve;
BrepFace bf = b.Faces[0]; // the first and only face of the BRep
Brep split = bf.Split(new[]{splitCurve}); // split by an array of curves
if (null != split)
foreach(BrepFace splitFace in split.Faces)
{
    Brep part = splitFace.DuplicateFace(); // duplicate the face into a BRep of its own
    doc.Objects.AddBrep(part);
}

see http://4.rhino3d.com/5/rhinocommon/html/M_Rhino_Geometry_BrepFace_Split.htm

Refer to this page for more info on the various elements of a BRep http://wiki.mcneel.com/developer/brepstructure

And no, a curve cannot be a BRep (Boundary Representation).

3

Works great, Menno, And thanks for the links, most educational.

Sam