The following VBA example creates an angular dimension that is linked to snap points. The dimension text is positioned in the center of the dimension arms.
Sub Test()
Dim shp1 As Shape
Dim snpVer As New SnapPoint, snp1 As New SnapPoint, snp2 As New SnapPoint
'Initialize the snap points to attach the dimension to; this placement should give us a 45 degree measurement.
snpVer.PositionX = 0.0
snpVer.PositionY = 0.0
snp1.PositionX = 10.0
snp1.PositionY = 0.0
snp2.PositionX = 10.0
snp2.PositionY = 10.0
Set shp1 = ActiveLayer.CreateAngularDimension(snpVer, snp1, snp2, 10.0, 5.0)
shp1.Dimension.ShowUnits = True
End Sub