BoxFrame.rvb

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' BoxFrame.rvb -- November 2009
' If this code works, it was written by Dale Fugier.
' If not, I don't know who wrote it.
' Works with Rhino 4.0.
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Option Explicit

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' http://wiki.mcneel.com/developer/scriptsamples/boxframe
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Sub BoxFrame()
  
  ' Local constants
  Const X = 0
  Const Y = 1
  Const Z = 2
  Const TOL = 0.01
  
  ' Local variables
  Dim box_points, box_object, box_center, box_plane
  Dim offset(2), dist(2), pfact(2), nfact(2)
  Dim xform(2), boxes(2)
  
  ' Prompt the user to define a box    
  box_points = Rhino.GetBox()
  If IsNull(box_points) Then Exit Sub

  ' Calculate half distances between corners    
  dist(X) = Rhino.Distance(box_points(0), box_points(1)) * 0.5
  dist(Y) = Rhino.Distance(box_points(0), box_points(3)) * 0.5
  dist(Z) = Rhino.Distance(box_points(0), box_points(4)) * 0.5
    
  ' Define axes offsets
  offset(X) = Rhino.GetReal("Thickness in X direction", 1.0, TOL, dist(X) - TOL)
  If IsNull(offset(X)) Then Exit Sub
    
  offset(Y) = Rhino.GetReal("Thickness in Y direction", 1.0, TOL, dist(Y) - TOL) 
  If IsNull(offset(Y)) Then Exit Sub
    
  offset(Z) = Rhino.GetReal("Thickness in Z direction", 1.0, TOL, dist(Z) - TOL) 
  If IsNull(offset(Z)) Then Exit Sub
    
  ' Do this for performance
  Call Rhino.EnableRedraw(False)    

  ' Calculate increasing scale factors
  pfact(X) = (dist(X) + offset(X)) / dist(X)
  pfact(Y) = (dist(Y) + offset(Y)) / dist(Y)
  pfact(Z) = (dist(Z) + offset(Z)) / dist(Z)

  ' Calculate decreasing scale factors
  nfact(X) = (dist(X) - offset(X)) / dist(X)
  nfact(Y) = (dist(Y) - offset(Y)) / dist(Y)
  nfact(Z) = (dist(Z) - offset(Z)) / dist(Z)
  
  ' Some stuff need for the scale transformation 
  box_center = Rhino.PointDivide(Rhino.PointAdd(box_points(0), box_points(6)), 2.0)
  box_plane = Rhino.PlaneFromPoints(box_points(0), box_points(1), box_points(3))
  box_plane = Rhino.MovePlane(box_plane, box_center)
  
  ' Define scale transformations
  xform(0) = Rhino.XformScale(box_plane, pfact(0), nfact(1), nfact(2))
  xform(1) = Rhino.XformScale(box_plane, nfact(0), pfact(1), nfact(2))
  xform(2) = Rhino.XformScale(box_plane, nfact(0), nfact(1), pfact(2))

  ' Create the box
  box_object = Rhino.AddBox(box_points)
  
  ' Create the boxes to difference
  boxes(0) = Rhino.TransformObject(box_object, xform(0), True)
  boxes(1) = Rhino.TransformObject(box_object, xform(1), True)
  boxes(2) = Rhino.TransformObject(box_object, xform(2), True)
  
  ' Do the difference
  Call Rhino.BooleanDifference(Array(box_object), boxes, True)
  
  ' Enable redraw
  Call Rhino.EnableRedraw(True)    
  
End Sub