' set a reference to the assembly component definintion.
' This assumes an assembly document is open.
Dim oAsmCompDef As AssemblyComponentDefinition
oAsmCompDef = ThisApplication.ActiveDocument.ComponentDefinition

'Iterate through all of the occurrences
Dim oOccurrence As ComponentOccurrence
For Each oOccurrence In oAsmCompDef.Occurrences
'check for and skip virtual components
If Not TypeOf oOccurrence.Definition Is VirtualComponentDefinition Then
	'set BOM as default if the component is visible
	If Component.Visible(oOccurrence.Name) = True Then
	Component.InventorComponent(oOccurrence.Name).BOMS​tructure = _
	BOMStructureEnum.kDefaultBOMStructure
	'set BOM as reference if the component is not visible
	ElseIf Component.Visible(oOccurrence.Name) = False Then
	Component.InventorComponent(oOccurrence.Name).BOMS​tructure = _
	BOMStructureEnum.kReferenceBOMStructure
	End If
Else
End If
Next