Create dimension relative to other dimension

By Adam Nagy

When you want to use the value of a dimension from another dimension, then you actually need to use the Parameter of that dimension. If you click on a dimension which is referencing another dimension's value, then you can see that both dimensions have an associated parameter, and the equation is based on those. Both dimensions are just simple dimensions based on a Parameter: in this case one is based on d5 and the other on d6:

If I wanted to recreate the above highlighted dimension then I could do it like this in VBA. Before running the code you need to go to the Sketch environment in the Part document, then select the dimension you want to reference from the new dimension and then shift-select the sketch line you want to dimension:

Sub AddDimension()
  Dim pd As PartDocument
  Set pd = ThisApplication.ActiveDocument
  Dim dc As DimensionConstraint
  Set dc = pd.SelectSet(1)
  Dim sl As SketchLine
  Set sl = pd.SelectSet(2)
  Dim sk As PlanarSketch
  Set sk = sl.Parent
  Dim tg As TransientGeometry
  Set tg = ThisApplication.TransientGeometry
  Dim pt As Point2d
  Set pt = tg.CreatePoint2d( _
    (sl.StartSketchPoint.Geometry.x + _
      sl.EndSketchPoint.Geometry.x) / 2, _
    sl.StartSketchPoint.Geometry.y + 0.5)
  Dim dc2 As TwoPointDistanceDimConstraint
  Set dc2 = sk.DimensionConstraints.AddTwoPointDistance( _
    sl.StartSketchPoint, _
    sl.EndSketchPoint, _
    kAlignedDim, _
    pt)

  dc2.Parameter.Expression = dc.Parameter.name + " * 2 ul"' If the sketch is consumed by a feature' this will get the lines updated
  Call sk.Solve
End Sub