I did youtube videos and a Web page to give more informations on how to print it and to modify it with FreeCAD.
Links : https://www.gisinb.ch/yt/impression3d/portal/portal.html
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and :
The author remixed this model.
I completely redesigned the Portal, in FreeCAD. The basis, top and bolt are squares. I added a kind of support to help the 3d printing.