Code:
Set document1 = CATIA.ActiveDocumentDim selection1 As Selection
Set selection1 = document1.Selection
selection1.Clear
Dim v4MasterModel1 As CATBaseDispatch
Set v4MasterModel1 = document1.GetItem("CAT_1000_1")
selection1.Add v4MasterModel1
selection1.Copy
Set documents1 = CATIA.Documents
Dim partDocument1 As Document
Set partDocument1 = documents1.Add("Part")
Dim product1 As CATBaseDispatch
Set product1 = partDocument1.GetItem("Part1")
Dim part1 As Part
Set part1 = partDocument1.Part
part1.Update
Set partDocument1 = CATIA.ActiveDocument
partDocument1.SaveAs "name.CATPart"