Attribute VB_Name = "Module1"
Sub CATMain()
Dim Datei As String
Datei = CATIA.FileSelectionBox("Startmodell wählen!", "*.CatPart", CatFileSelectionModeOpen)
CATIA.Documents.NewFrom (Datei)
Dim partDocument1 As Document
Set partDocument1 = CATIA.ActiveDocument

Dim part1 As Part
Set part1 = partDocument1.Part

Dim parameters1 As Parameters
Set parameters1 = part1.Parameters

Dim realParam1 As Parameter
Set realParam1 = parameters1.Item("Breite")
neuebreite = InputBox("Wert für Breite eingeben!", "Breite", "20")
realParam1.value = neuebreite
part1.Update
End Sub