var dir = s.Faces[0].IsClosed(0) ? 0 : s.Faces[0].IsClosed(1) ? 1 : 2;
if(dir != 2)
A = Brep.ChangeSeam(s.Faces[0], dir, p, Rhino.RhinoDoc.ActiveDoc.ModelAbsoluteTolerance) ?? s;
else
Component.AddRuntimeMessage(GH_RuntimeMessageLevel.Warning, "Surface is not closed and the seam cannot be adjusted");
SrfSeam.gh (62.8 KB)