The FeatherEdge property returns or specifies the type of feathering edge for a drop shadow. Values range from 0% to 100%. This property returns cdrEdgeType.
Examples:
The following VBA example applies 50% outside feathering with inverse squared edges to all drop shadows on the active page.
Sub Test()
Dim s As Shape
For Each s In ActivePage.Shapes
If s.Type = cdrDropShadowGroupShape Then
With s.Effect.DropShadow
.FeatherType = cdrFeatherOutside
.FeatherEdge = cdrEdgeInverseSquared
.Feather = 50
End With
End If
Next s
End Sub