Option Explicit

Sub Pattern()

Dim i1,i2,i3
Dim strBaseSurface 
Dim intDomainU,intDomainV, dblU,dblV, arrParameter, dblBaseU,dblParameterU,dblParameterV
Dim arrNormal,arrPntOnPar
Dim arrCPtBody(),arrCount
Dim dblShiftV,dblShiftU
Dim arrPoint


'////////////////////////////////////////
'///////////  Parameters  ///////////////
'////////////////////////////////////////

Dim parDivisionU,parDivisionV
Dim parShiftV,parShiftU

'Parameter which defines division of pattern in U and V direction.
parDivisionU = 140
parDivisionV = 140

'Parameter which defines pattern itself, by shifting control points.
'Parameter value must be between -2 and 2.
parShiftV = 0.5
parShiftU = 0.5

'////////////////////////////////////////
'///////////  Parameters  ///////////////
'////////////////////////////////////////


  
'Prompts user to pick “bone” surface, and calculates division of pattern.
 strBaseSurface = Rhino.GetObject("Select Srf.",8)
 intDomainU = Rhino.SurfaceDomain (strBaseSurface, 0)
 intDomainV = Rhino.SurfaceDomain (strBaseSurface, 1)
 
 dblU = (intDomainU(1)-intDomainU(0))/parDivisionU
 dblV = (intDomainV(1)-intDomainV(0))/parDivisionV
 ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
 'First "For" defines new position of control point in V direction according to parameters.
 dblBaseU = dblU
 i3=-1
 For i1=0 To parDivisionU-4
  
    dblBaseU = dblBaseU + dblU
    dblParameterV = 0
    
  
    If i1 = 1 Then
      dblShiftV = 0
    End If
  
    If i1 > 1 Then
        If i1 Mod 2 = 1 Then
          dblShiftV = 0
        End If
    End If
  
    If i1 = 0 Then
      dblShiftV = parShiftV
    End If
  
    If i1 > 1 Then
        If i1 Mod 2 = 0 Then
          dblShiftV = parShiftV
        End If
    End If
    
    
 'Second "For" defines new position of control point in U direction according to parameters.
 dblParameterV = (dblV*dblShiftV)+ dblV
 For i2=0 To parDivisionV-4
 i3=i3+1
  
  
  
    If i2 = 1 Then
      dblShiftU = 0
    End If
  
    If i2 > 1 Then
        If i2 Mod 2 = 1 Then
          dblShiftU = 0
        End If
    End If
  
    If i2 = 0 Then
      dblShiftU = parShiftU
    End If
  
    If i2 > 1 Then
        If i2 Mod 2 = 0 Then
          dblShiftU = parShiftU
        End If
    End If
    
  
 dblParameterU = dblBaseU + (dblU*dblShiftU)
 dblParameterV = dblParameterV + dblV
 
 
 
 'This part creates 3D point based on newly calculated UV parameters of the surface
 'and adds a normal vector at this point as a direction of movement.
 arrParameter = Array(dblParameterU,dblParameterV)
 arrPntOnPar = Rhino.SurfaceEvaluate (strBaseSurface, arrParameter, 1)
 arrNormal = Rhino.SurfaceNormal (strBaseSurface, arrParameter)
 ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
 
 
 'This part tests if the 3D point is "odd or even" point of pattern
 'and according to result it reverse direction of movement or not. 
    If i1 = 1 Then
       arrNormal = Rhino.VectorReverse (arrNormal)
    End If
  
    If i1 > 1 Then
        If i1 Mod 2 = 1 Then
          arrNormal = Rhino.VectorReverse (arrNormal)
        End If
    End If
 
    If i2 = 1 Then
      arrNormal = Rhino.VectorReverse (arrNormal)
    End If
  
    If i2 > 1 Then
        If i2 Mod 2 = 1 Then
          arrNormal = Rhino.VectorReverse (arrNormal)
        End If
    End If
  '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
  
  
   
 'This part stores newly calculated points of pattern in to dynamic array. 
 arrPoint = Rhino.PointAdd (arrPntOnPar(0), arrNormal)
 ReDim Preserve arrCPtBody(i3) 
 arrCPtBody(i3) = arrPoint
 '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
 Next
 Next
 
 'This part finally adds new surface with plastic pattern according to parameters defined at beginning.
 arrCount = Array(parDivisionU-3,parDivisionV-3)
 Rhino.AddSrfPtGrid  arrCount, arrCPtBody
 ''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
 
End Sub

Pattern