Prueba con esto:
Sub CATMain()
Dim PD1 As Document
Set PD1 = CATIA.ActiveDocument
Dim S1 As Selection
Set S1 = PD1.Selection
Set visProp1 = CATIA.ActiveDocument.Selection.VisProperties
visProp1.SetRealOpacity 255,1
S1.Clear
End Sub
Selecciona la raiz del arbol y ejecuta la macro.