Can I transfer my AC20 project to an architect using AC17?

[Gus]

There has been a change of project architects on a project I have been working on. I have been using ArchiCAD 20 and the new contracted architect is using ArchiCAD 17. Any thoughts on the best way to transfer the project to him, so that he can continue the project using ArchiCAD 17?

[Anonymous]

If you have each version in between you can "Save As" AC19 from AC20, open in 19 and "Save As" AC18, open in 18 and "Save As" AC17.
Shown below is the Save As dialogue from AC19.

Otherwise I'm not sure.

You may lose bits and pieces as it is saved back to the earlier versions

[Laszlo Nagy]

Before saving to a previous version you should move all your placed Library Parts into the Embedded Library because those Library Parts will then be converted to the previous version during saving as previous version.
Still there could be data loss if a library part uses a GDL command that was not available in the previous version.

[Erwin Edel]

If you have a license for ArchiCAD20, I think you should be able to download and install the older versions of ArchiCAD and do a very annoying save back to ArchiCAD17 by going back to each version. Just check your account on myarchicad.com

I'd probably start by setting up the ArchiCAD17 library on your ArchiCAD20 project, once you have downloaded and installed it, and see what kind of problems that might give. Any custom objects need to be put in the embedded library and saved back along with the pln on each version and you still might run into some problems with GDL compatability.

Surfaces will be interesting once you go from 18 to 17, due to no cinerender.