Option Explicit
'Script written by rwr
'Script is open source
'Script version Saturday, August 16, 2009 12:58:23 PM
'------------------------------------------------------------------------------
' Purpose:    Creates a counter fold folded-plate on a context surface
'------------------------------------------------------------------------------

Call Main()
Sub Main()
	Dim strsrf : strsrf = rhino.getobject("select a surface to populate",8)
	If IsNull(strSrf) Then Exit Sub
	
	Dim uDiv : uDiv = Rhino.GetInteger("divisions in U direction", 25)
	Dim vDiv : vDiv = Rhino.GetInteger("divisions in V direction", 3)
	
	'declare offset height variable and value
	Dim height : height = Rhino.GetReal ("offset height",30)
	
	Dim uDomain : uDomain = Rhino.SurfaceDomain(strsrf,0)
	Dim vDomain : vDomain = Rhino.SurfaceDomain(strsrf,1)
	
	Dim ustep : ustep = (uDomain(1)-uDomain(0))/uDiv
	Dim vstep : vstep = (vDomain(1)-vDomain(0))/vDiv
	
	Dim u, v
		
	'Rhino.EnableRedraw(False)
	
	For u = 0 To uDomain(1)-ustep Step ustep
		For v = 0 To vDomain(1)-vstep Step vstep 
			
			Dim uvPoint, arrData, proPoint1, proPoint2, proPoint3, proPoint4, proPoint5, proPoint6, proPoint7, proPoint8, proPoint9 

			'call srfCurvature function
			uvPoint = Array (u,v)
			arrData = srfCurvature (strsrf, uvPoint)
			'call offsetCalc function, offset distance is 'height'		
			proPoint1 = offsetCalc(arrData, 0)
			
			'call srfCurvature function
			uvPoint = Array (u,v+vstep/2)
			arrData = srfCurvature (strsrf, uvPoint)
			'call offsetCalc function, offset distance is 'height'		
			proPoint2 = offsetCalc(arrData, height)
			
			'call srfCurvature function
			uvPoint = Array (u+ustep/2,v+vstep/2)
			arrData = srfCurvature (strsrf, uvPoint)
			'call offsetCalc function, offset distance is 'height'		
			proPoint3 = offsetCalc(arrData, 0)
			
			'call srfCurvature function
			uvPoint = Array (u+ustep/2,v)
			arrData = srfCurvature (strsrf, uvPoint)
			'call offsetCalc function, offset distance is 'height'		
			proPoint4 = offsetCalc(arrData, height)
			
			'call srfCurvature function
			uvPoint = Array (u+ustep,v)
			arrData = srfCurvature (strsrf, uvPoint)
			'call offsetCalc function, offset distance is 'height'		
			proPoint5 = offsetCalc(arrData, 0)
			
			'call srfCurvature function
			uvPoint = Array (u+ustep,v+vstep/2)
			arrData = srfCurvature (strsrf, uvPoint)
			'call offsetCalc function, offset distance is 'height'		
			proPoint6 = offsetCalc(arrData, height)
			
			'call srfCurvature function
			uvPoint = Array (u,v+vstep)
			arrData = srfCurvature (strsrf, uvPoint)
			'call offsetCalc function, offset distance is 'height'		
			proPoint7 = offsetCalc(arrData, 0)
			
			'call srfCurvature function
			uvPoint = Array (u+ustep/2,v+vstep)
			arrData = srfCurvature (strsrf, uvPoint)
			'call offsetCalc function, offset distance is 'height'		
			proPoint8 = offsetCalc(arrData, height)
			
			'call srfCurvature function
			uvPoint = Array (u+ustep,v+vstep)
			arrData = srfCurvature (strsrf, uvPoint)
			'call offsetCalc function, offset distance is 'height'		
			proPoint9 = offsetCalc(arrData, 0)
				
			'create planar surfaces through 3 points
			Dim strSrf1, strSrf2, strSrf3, strSrf4, strSrf5, strSrf6, strSrf7, strSrf8
			strSrf1 = rhino.AddSrfPt(array(proPoint1, proPoint2, proPoint3))
			strSrf2 = rhino.AddSrfPt(array(proPoint1, proPoint3, proPoint4))
			strSrf3 = rhino.AddSrfPt(array(proPoint4, proPoint3, proPoint5))
			strSrf4 = rhino.AddSrfPt(array(proPoint5, proPoint3, proPoint6))
			strSrf5 = rhino.AddSrfPt(array(proPoint2, proPoint7, proPoint3))
			strSrf6 = rhino.AddSrfPt(array(proPoint3, proPoint7, proPoint8))
			strSrf7 = rhino.AddSrfPt(array(proPoint3, proPoint8, proPoint9))
			strSrf8 = rhino.AddSrfPt(array(proPoint3, proPoint9, proPoint6))
		
		Next
	Next
	'Rhino.EnableRedraw(True)
End Sub

Function srfCurvature (strsrf, uvPoint)
	Dim arrPoint, arrParam
	'evaluate point
	arrPoint = Rhino.EvaluateSurface (strsrf, uvPoint)
	'returns the UV parameter of the point on the surface that is closest to the current uv step
	arrParam = Rhino.SurfaceClosestPoint(strsrf, arrPoint)
	If IsArray(arrParam) Then		
		'returns the curvature of a surface at a U,V parameter
		srfCurvature = Rhino.SurfaceCurvature(strsrf, arrParam)
		If IsArray(srfCurvature) Then
		End If
	End If
End Function


Function offsetCalc(arrData, height)
	Dim vscaled
	vscaled = VectorScale(arrData(1),height)
	offsetCalc = VectorAdd(vscaled,arrData(0))
End Function

'function by RMA, "vectors.rvb"
Function VectorAdd(v1, v2)

	VectorAdd = Null
	If Not IsArray(v1) Or (UBound(v1) <> 2) Then Exit Function
	If Not IsArray(v2) Or (UBound(v2) <> 2) Then Exit Function
	VectorAdd = Array(v1(0) + v2(0), v1(1) + v2(1), v1(2) + v2(2))
End Function

'function by RMA, "vectors.rvb"
Function VectorScale(v, d)

	VectorScale = Null
	If Not IsArray(v) Or (UBound(v) <> 2) Then Exit Function
	If Not IsNumeric(d) Then Exit Function
	VectorScale = Array(v(0) * d, v(1) * d, v(2) * d)
End Function