Sub test()
' Имя детали в сборке "Кирпич"
Dim oAsmDoc As AssemblyDocument
Set oAsmDoc = ThisApplication.ActiveDocument
Dim oAsmDef As AssemblyComponentDefinition
Set oAsmDef = oAsmDoc.ComponentDefinition
Dim oLeafOccs As ComponentOccurrencesEnumerator
Set oLeafOccs = oAsmDef.Occurrences.AllLeafOccurrences
Dim oOcc As ComponentOccurrence
For Each oOcc In oLeafOccs
If oOcc.Name = "Кирпич" Then
' Здесь вставляй обработку выбраной по имени сборки
Set Базовая_деталь = oAsmDoc.ComponentDefinition.Occurrences.ItemByName("Кирпич")
End If
Next
End Sub