Hi Shawon, I'm not familiar with FreeCAD, but there are a few general methods for connecting Pharo with other software applications. The lowest-level method would be to use the Pharo uFFI (Universal Foreign Function Interface), which would be appropriate if FreeCAD has an API/ABI (Application Programming|Binary Interface); this would allow you to directly connect Pharo via a C programming interface. There is a PDF booklet to introduce you to the uFFI here: https://github.com/SquareBracketAssociates/Booklet-uFFI/releases Pharo can also control other software through a command shell interface. This would allow a Pharo application to launch FreeCAD (with command line parameters); you may need to do this to get FreeCAD running in order to connect to it. Christopher Fuhrman has written a good description of how this can be done here: https://fuhrmanator.github.io/2019/03/16/LibC-Pharo-experiments.html And since you are learning about Pharo, you will probably want to read at least the first two of three Pharo Tutorial Series booklets. Here is the first: https://github.com/SquareBracketAssociates/PharoByExample80/releases and the second one is here, third row from the bottom, "Deep into Pharo": http://books.pharo.org/ Have fun, and ask questions as you need to! -Ted -- Sent from: http://forum.world.st/Pharo-Smalltalk-Developers-f1294837.html