Summary: How to reverse engineer an interpolated curve using RhinoScript.
Is it possible to obtain the original points used when creating an interpolated curve using Rhino's InterpCrv command or RhinoScript's AddInterpCurveEx method?
If the curve has a degree of 3, then the answer is yes. Just get the curve's knots, or knot vector, and then evaluate each knot value.
The following example demonstrates how to extract an interpolated curve's original construction points.
Function ExtractInterpCrvPoints(curve) ' local variables Dim points(), knots, i ' default result ExtractInterpCrvPoints = Null ' verify the curve If Not IsNull(curve) And Rhino.IsCurve(curve) Then ' verify the degree of the curve If Rhino.CurveDegree(curve) = 3 Then ' get the curve's knots knots = Rhino.CurveKnots(curve) ' verify the curve's knots If IsArray(knots) Then ' evaluate the curve at each knot value ReDim points(UBound(knots)) For i = 0 To UBound(knots) points(i) = Rhino.EvaluateCurve(curve, knots(i)) Next ' cull any duplicate points ExtractInterpCrvPoints = Rhino.CullDuplicatePoints(points) End If End If End If End Function