Option Explicit
'Script written and copyrighted by Ted Ngai	Feb 2007
'This work is licensed under a  Creative Commons Attribution-Share Alike 3.0 United States License.
'http://creativecommons.org/licenses/by-sa/3.0/us/

Call HexOnSurf()

Sub HexOnSurf()
	
	'Rhino.Command "_SelAll Delete"
	
	'Get Surface
	Dim strObject,arrDomU, arrDomV
	strObject = Rhino.GetObject ("Select Surface", 8, True)
	If IsNull(strObject) Then Exit Sub

	arrDomU = Rhino.SurfaceDomain(strObject, 0)
	arrDomV = Rhino.SurfaceDomain(strObject, 1)
	 
	Dim u,v,t
	Dim stp : stp = Pi/3 
	Dim Hex_uCount : Hex_uCount = 10
	Dim Hex_vCount : Hex_vCount = 10
	Dim off_int : off_int = 4
	Dim hex_off : hex_off = 0.9
	Dim hex,cir
	
	Dim uLength : uLength = Hex_uCount*(3*Cos(stp))+Cos(stp)
	Dim vLength : vLength = Hex_vCount*(2*Sin(stp))+Sin(stp)
	Dim dUspacing : dUspacing = (arrDomU(1)-arrDomU(0))/(uLength)
	Dim dVspacing : dVspacing = (arrDomV(1)-arrDomV(0))/(vLength)

	Call Rhino.EnableRedraw(False)
	For v = 0 To Hex_vCount-1
		For u = 0 To Hex_uCount-1
			hex = DrawHex (strObject,u,v,stp,dUspacing,dVspacing,hex_off,off_int)
		Next
	Next
	Call Rhino.EnableRedraw(True)
End Sub

Function DrawHex (ByVal strObject,ByVal u,ByVal v,ByVal stp,ByVal dU,ByVal dV, ByVal hex_off, ByVal off_int)
	
	Dim t
	Dim c1,c2
	Dim x,y,z
	Dim Pi : Pi = Rhino.Pi
	Dim arrPointsN,arrPointsO
	Dim arrParam,arr3DPts
	
	For t = 0 To 2*Pi Step stp 

		x = u+u*Cos(stp)+2*Cos(stp)+(Cos(t)*hex_off)
		y = (2*v*Sin(stp))+(Sin(stp)*(0)^(u Mod 2))+Sin(stp)+(Sin(t)*hex_off)
		z = off_int
		
		arrParam = Array((x*dU),(y*dV))
		arr3DPts = Rhino.EvaluateSurface(strObject, arrParam)
		
		'Offset Curve
		Dim arrNormal,crvScale
		Dim arrNormalOffset,arrOffsetPts
						
		arrNormal = Rhino.SurfaceCurvature(strObject, arrParam)
		'crvScale =  (arrNormal(2)* z)- z
		arrNormalOffset = Rhino.VectorScale(arrNormal(1),1*z)
		arrOffsetPts = Rhino.VectorAdd(arr3DPts, arrNormalOffset)
		
		arrPointsN = AddPtToArray(arrPointsN, arr3DPts)
		arrPointsO = AddPtToArray(arrPointsO,arrOffsetPts)
		 
	Next 
	c1=Rhino.AddPolyline (arrPointsN)
	c2=Rhino.AddPolyline(arrPointsO)
	Rhino.AddLoftSrf Array(C1,C2)
	
	DrawHex=arrPointsN
End Function

Function AddPtToArray (arrPoints, arrPt)

	If IsArray(arrPoints) Then
		ReDim Preserve arrPoints( UBound(arrPoints) + 1 )
	Else
		ReDim arrPoints(0)
	End If
   
	arrPoints(UBound(arrPoints))= arrPt
	
	AddPtToArray = arrPoints

End Function