Here’s the code snippet:
dim.TextFormula = "~ %<CurveLength(\"" + str(segId) + "\")>%\nRadius"
dim.ArrowheadType1 = Rhino.DocObjects.DimensionStyle.ArrowType.Dot
dim.ArrowheadType2 = Rhino.DocObjects.DimensionStyle.ArrowType.Dot
dim.ArrowSize = 1
print dim.ArrowSize
rdim = sc.doc.Objects.AddLinearDimension(dim, rattr)
ordim = Rhino.DocObjects.ObjRef(rdim).Object()
print "---------"
print ordim.Geometry.ArrowSize
Output with ArrowSize = 1:
Output with ArrowSize = 0.99:
Output with ArrowSize = 1.001:
1.850 is the annotation style default value.