Sub rrrr()
Dim partDoc As PartDocument: Set partDoc = ThisApplication.ActiveDocument
Dim CompDef As PartComponentDefinition: Set CompDef = partDoc.ComponentDefinition
Dim DerivedComp As DerivedPartComponent: Set DerivedComp = CompDef.ReferenceComponents.DerivedPartComponents(1)
Dim DerivedDef As DerivedPartDefinition: Set DerivedDef = DerivedComp.Definition
If DerivedDef.Type = kDerivedPartUniformScaleDefObject Then
Dim DerivedMirorDef As DerivedPartUniformScaleDef: Set DerivedMirorDef = DerivedDef
If DerivedMirorDef.MirrorPlane <> kDerivedPartNoMirrorPlane Then
MsgBox ("Is Miror Part")
End If
End If
End Sub