You could explode the brep into individual breps:
Dim crvlist As New list(Of curve)For Each bf As brepface In x.facescrvlist.addrange(curve.JoinCurves(bf.tobrep.GetWireframe(-1)))Nexta = crvlist
by its own tangent vector on the curve... and this happens to the last item. Here's the algorithm:
B0 ----> B1
B1 ----> B2
B2 ----> B3
B3 ----> B4
...
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