For the development of python scripts using pycatia it’s recommended you follow the steps detailed below.

To run pre-existing scripts windows builds are available

The Short Version

This assumes python 3.6 or later is already installed and you know how and when (all the time really) to use virtual environments.

To install from pypi:

pip install pycatia

To get the latest development version from github:

   git clone
   # install pycatia requirement
   pip install -r requirements\requirements.txt

To upgrade your current installed version::

   pip install pycatia --upgrade

The Long Version

It’s unlikely that the pycatia end user will have administrator access to their workstation. If that is the case you’ll need to get someone with the appropriate permissions to install python and the virtualenv module.

Installing Python

  • Download python 3 (3.6 or later) from

  • Install python. Ensure to check the box to add python to environment variables.

  • Install virtualenv for python. From the adminsitrator command prompt run the following:

    python -m pip install virtualenv

Create The Virtual Environment

The virtual environment allows you to install python packages in a sand boxed environment away from the python installation itself.

  • Create a new directory where you’ll be creating your pycatia scripts. For this example this will be c:\Users\<username>\python\pycatia-scripts

  • Change directory into this folder:

    cd c:\Users\<username>\python\pycatia-scripts
  • Create the virtual environment:

    python -m virtualenv env
  • Activate the virtual environment:


You should see the command prompt change to something like this:

(env) c:\Users\<username>\python\pycatia-scripts>
  • Install pycatia:

    python -m pip install pycatia

All done!


pycatia scripts will need this virtual env activated prior to running.

Confirm Successful Install


Starting the CATIA V5 session is important!

  • Start a CATIA V5 session.

  • Open the CMD prompt and activate the virtual environment if you haven’t already done so.

  • Type python. You will then enter the python interpreter.

(env) C:\Users\<username>\python\pycatia-scripts>python
Python 3.6.7 (v3.6.7:6ec5cf24b7, Oct 20 2018, 13:35:33) [MSC v.1900 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
  • Now import the catia application object.

from pycatia import catia
caa = catia()
# q to quit help
# open a new .CATPart
documents = caa.documents
  • To exit the python interpreter.



If there are no error messages and you don’t see a new CATPart ensure you don’t have any hidden CATIA / CNEXT processes running in task manager.


Sometimes the COM object isn’t registered properly when CATIA is installed. If the above isn’t working you may need to re-install.