SelSmallSrf.rvb

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' SelSmallSrf.rvb -- November 2012
' If this code works, it was written by Dale Fugier.
' If not, I don't know who wrote it.
' Works with Rhino 4 and 5.
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Option Explicit

Public g__dblArea

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' Selects surfaces whose area is less than or equal to a user-specified area.
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Sub SelSmallSrf
  
  ' Declare constants
  Const RH_SRF = 8
  
  ' Declare local variables
  Dim dblArea, minArea, srfArea
  Dim arrSrfs, strSrf, nCount

  ' The minimum area the user can specify
  minArea = Rhino.UnitAbsoluteTolerance

  ' Make sure global variable is initialized
  If IsEmpty(g__dblArea) Then
    g__dblArea = minArea
  ElseIf IsNull(g__dblArea) Then
    g__dblArea = minArea
  End If

  ' Validate global variable
  If (g__dblArea < minArea) Then g__dblArea = minArea
  
  ' Prompt the user for the surface area
  dblArea = Rhino.GetReal("Maximum area of surface to select", g__dblArea, minArea)
  If IsNull(dblArea) Then Exit Sub
    
  g__dblArea = dblArea
  nCount = 0
  
  ' The all of the surfaces in the document  
  arrSrfs = Rhino.ObjectsByType(RH_SRF)
  If IsArray(arrSrfs) Then
    Call Rhino.EnableRedraw(False)
    For Each strSrf In arrSrfs
      ' We only need to process surfaces that are both
      ' selectable and not already selected.
      If Rhino.IsObjectSelectable(strSrf) And Not Rhino.IsObjectSelected(strSrf) Then
        ' Calculate surface and compare
        srfArea = Rhino.SurfaceArea(strSrf)
        If IsArray(srfArea) Then
          If (srfArea(0) <= g__dblArea) Then
            Call Rhino.SelectObject(strSrf)
            nCount = nCount + 1
          End If
        End If
      End If
    Next
    Call Rhino.EnableRedraw(True)
  End If
  
  ' Report what happened
  If (0 = nCount) Then
    Call Rhino.Print("0 small surfaces selected.")
  ElseIf (1 = nCount) Then
    Call Rhino.Print("1 small surface selected.")
  Else
    Call Rhino.Print(CStr(nCount) & " small surfaces selected.")
  End If

End Sub