AutoCAD VBA - Adding new dimension style

The following article will describe how to add/edit a dimension style through AutoCAD VBA.

AutoCAD VBA has its quirks and when it comes to dimensions and controlling how they look through VBA.  This is where AutoCAD can be vividly confusing. The real trick is to understand a simple concept about dimension styles in AutoCAD. To use some home construction terms, they are not built “from the ground up”, they are "remodeled". That is to say, you have to start with everything already defined in a dimension style and then you change it to suit your needs. With that in mind, here is a quick snippet of how to create a new dimension style.

You first add a new dimension style to the drawing. It has all of its variables set by the current way the drawing is defined. You then alter the variables how you want them to be in your new dimension style and then "copy" them into your new dimension style. It is a simple concept but confusing if you are not aware of the quirk of "copying" these to your new dimension style. Keep in mind that the variables defined in the code are only a portion of the total number of dimension variables that exist. You will need to add or subtract the variables you wish to control in your dimension style.

This same concept is also how you alter the settings of an existing dimension style. The commented lines of code show how to alter an existing dimension style. Editing an existing dimension style requires the creation of a new dimension style first and then copying those variables into the original style. The steps are as follows; you create a new dimension style, alter the variables, and then restore the original dimension style and "copy" the variables back into the original.

Public Sub UgDimStyle_CreateNew( _
                      Optional ByVal sDimStyName As String = "Standard_Dim")
                      '------------------------------------------------------------------------------
                      '
                      '
                      '------------------------------------------------------------------------------
                      Dim CurDimStyle As AcadDimStyle
                      Dim NewDimstyle As AcadDimStyle
                      Dim iAltUnits As Integer
                      Dim dDimScale As Double
                      '''''''''''''''''''''''''''''''''''''''
                      'Save copy of current dimstyle
                      Set CurDimStyle = ThisDrawing.ActiveDimStyle
                      
                      'Create new dimstyle
                      Set NewDimstyle = ThisDrawing.DimStyles.Add(sDimStyName)
                      
                      'Set newly created dimstyle current
                      ThisDrawing.ActiveDimStyle = NewDimstyle
                      
                      'Save the target "dimvar" values
                      dDimScale = ThisDrawing.GetVariable("Dimscale")
                      iAltUnits = ThisDrawing.GetVariable("Dimalt")
                      '------------------------------------------------------------------------------
                      'Alter the target "dimvar" values
                      '------------------------------------------------------------------------------
                      ThisDrawing.SetVariable "DIMSCALE", 1# 'will control size of dim text
                      ThisDrawing.SetVariable "DIMASZ", 2.5 'arrowhead size
                      ThisDrawing.SetVariable "DIMATFIT", 2 'arrow-text arrangement
                      ThisDrawing.SetVariable "DIMAZIN", 3 '0 suppression before/after angular
                      ThisDrawing.SetVariable "DIMBLK", "" 'special arrow blk
                      ThisDrawing.SetVariable "DIMDLE", 0 'dim line extension past extension
                      ThisDrawing.SetVariable "DIMDLI", 10 'dist between baseline dims
                      ThisDrawing.SetVariable "DIMDSEP", "." 'decimal separator
                      ThisDrawing.SetVariable "DIMEXE", 1 'dim line extension past extension
                      ThisDrawing.SetVariable "DIMEXO", 1 'dim offset from origin
                      'ThisDrawing.SetVariable "DIMFIT", 5 'control fit if not enough space
                      ThisDrawing.SetVariable "DIMGAP", 2 'gap around text
                      ThisDrawing.SetVariable "DIMJUST", 0 'text placement - above centered
                      ThisDrawing.SetVariable "DIMLFAC", 1# 'length scaling
                      ThisDrawing.SetVariable "DIMTAD", 1 'text to dim placement - above
                      ThisDrawing.SetVariable "DIMTIH", 0 'aligned with dim
                      ThisDrawing.SetVariable "DIMTIX", 0 'force inside
                      ThisDrawing.SetVariable "DIMTMOVE", 0 'dim moves with text
                      ThisDrawing.SetVariable "DIMTSZ", 0 'draw arrowheads
                      ThisDrawing.SetVariable "DIMTXT", 3.5 'text height
                      ThisDrawing.SetVariable "DIMTZIN", 12 '0 suppression before/after tol
                      ThisDrawing.SetVariable "DIMUNIT", 2 'unit format - decimal
                      ThisDrawing.SetVariable "DIMZIN", 12 '0 suppression before/after
                      
                      'Copy new document dimvar settings into new dimstyle
                      NewDimstyle.CopyFrom ThisDrawing
                      
                      'Set original dimstyle current
                      'ThisDrawing.ActiveDimStyle = CurDimStyle
                      
                      'Restore the altered "dimvar" values
                      ''ThisDrawing.SetVariable "Dimscale", dDimScale
                      ''ThisDrawing.SetVariable "Dimalt", iAltUnits
                      
                      'Copy restored document dimvar settings into original dimstyle
                      ''CurDimStyle.CopyFrom ThisDrawing
                      
                      Set CurDimStyle = Nothing
                      Set NewDimstyle = Nothing
                      End Sub

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