CATIA V5/DMU Navigator-Programming with Python

Ifyou want to automate CATIA V5 or DMU Navigator with Python you need Pywin32 and Python for Windows or Activestates ActivePython for Windows. Python is free software and you can develop professional applications with all advantages of Python for CATIA V5 or DMU Navigator.

To develop a small application which interacts to CATIA V5 you only have to download your prefered Python Distribution for Windows and can start developing applications for CATIA V5 or DMU Navigator (this should be running when testing the application).

If you have done that you can test it with this source code:

import win32com.client
a = win32com.client.Dispatch('catia.application')
for i in range(doc.Products.Count):
    print 'Part Number:', doc.Products.Item(i+1).PartNumber

This small example prints out the part names of a loaded CATProduct.

DMU Navigator

If you want to automate DMU Navigator, you can use this dispatch string:

import win32com.client
# Following doesn`t work with CATIA V5 R16 and later
a = win32com.client.Dispatch('DMU.application')

Other examples can be found in the script collection.

Important notes

If you want to use early binding for the CATIA V5 object libraries you can use the Makepy utility from Pythonwin. After that every object and its methods will be usable from the pulldown menu while typing and you can have a performance advantage. You should use makepy for every object library which you want to use e.g. “ProductStructure Object Library” for working with CATProducts). But not for the “CATIA V5 Interfaces Objekt Library”!

If you do that every application which uses early binding for the “CATIA V5 Interfaces Objekt Library” will not work ! A workaround is not to use makepy for the “CATIA V5 Interfaces Objekt Library” or use explicit late binding “(import win32com.client.dynamic as the first line).

For starting developing applications with Python for CATIA V5 you should use the manual V5Automation.chm which you can find in the bin-directory of CATIA V5. You will see that you can develop Python applications in the same way like VB with the builtin VB editor.

If you have problems to access the COM Interface from CATIA V5 (eg. no object libraries from CATIA V5 in makepy) please check whether CATIA V5 was registrated as a COM server. If not you can do that with cnext.exe /regserver in the CATIA V5 bin-directory. Then everything should work well…

More on Microsofts Component Object Model (COM) and Python

More information for developing with Python for COM applications with Pywin32 you can find in this excellent book.

Python Programming on Win32
by Mark Hammond, Andy Robinson
ISBN: 1-56592-621-8
652 pages. January 2000.

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