Option Explicit
'Script written by <David Mans>
'Script copyrighted by <NeoArchaic Design>
'Script version Sunday, May 03, 2009 1:54:38 PM

Call Main()
Sub Main()
	Dim Curves, SM, DN

	Curves= Rhino.GetObjects("Select Curves",4)
	If isNull(Curves) Then Exit Sub

	SM = Rhino.GetBoolean("Blend Type",array("Type","Straight","Smooth"),array(False))
	If isNull(SM) Then Exit Sub

	DN = Rhino.GetReal("Blend Density",5,1)
	If isNull(SM) Then Exit Sub

	Call Rhino.EnableRedraw(False)
	If uBound(Curves) > 0 Then
		Call BlendCurves(Curves,SM(0),DN)
	Else
		Call Rhino.Print("2 or more curves required")
	End If

	Call Rhino.EnableRedraw(True)
End Sub
Function BlendCurves(arrCurves,blnSmooth,dblDensity)
	BlendCurves = Null
	Dim i,j,p
	Dim count, max, dMax
	Dim arrptCount(), arrCrvDeg(), arrPointSet(),arrPts(), arrCrvDom(),arrCrvStep(),arrBlndCrvPt()
	Dim arrBlendCurve(), arrCtrlCrv()

	Dim dblSmoothness
	If blnSmooth = False Then
		dblSmoothness = 1
	Else
		dblSmoothness = 3
	End If

	count = Ubound(arrCurves)
	ReDim arrptCount(count),  arrCrvDeg(count), arrCrvDom(count), arrPointSet(count), arrPts(count)

	'get control point count
	For i = 0 To count Step 1
		arrptCount(i) = Rhino.CurvePointCount(arrCurves(i))
		arrCrvDeg(i) = Rhino.CurveDegree(arrCurves(i))
	Next
	'determine max point count
	max = Rhino.Max(arrptCount)
	dMax= Rhino.Max(arrCrvDeg)

	'rebuild curves with max control point count
	For i = 0 To count Step 1
		Call Rhino.RebuildCurve(arrCurves(i),dMax, max)
		arrPointSet(i) = Rhino.CurvePoints(arrCurves(i))
	Next

	max = max-1
	ReDim arrCtrlCrv(max), arrCrvDom(max), arrCrvStep(max), arrBlndCrvPt(max)
	'create control curves
	For i = 0 To max Step 1
		For j = 0 To count Step 1
			arrPts(j) = arrPointSet(j)(i)
		Next
		arrCtrlCrv(i)= Rhino.AddInterpCurve(arrPts,dblSmoothness)
		arrCrvDom(i) = Rhino.CurveDomain(arrCtrlCrv(i))
		arrCrvStep(i)= (arrCrvDom(i)(1)-arrCrvDom(i)(0))/(count*dblDensity)
	Next
	'create blended curves
	ReDim arrBlendCurve(count*dblDensity)
	For i = 0 To count*dblDensity Step 1
		For j = 0 To max Step 1
			arrBlndCrvPt(j) = Rhino.EvaluateCurve(arrCtrlCrv(j),arrCrvDom(j)(0)+i*arrCrvStep(j))
		Next
		arrBlendCurve(i) = Rhino.addcurve(arrBlndCrvPt,dMax)
	Next
	'delete control curves
	Call Rhino.DeleteObjects(arrCtrlCrv)
	Call Rhino.DeleteObjects(arrCurves)

	BlendCurves = array(arrBlendCurve,arrCtrlCrv)
End Function