Dear Gabor,
This is a known topic which can be answer in different method.
Yes you are right, there is no direct setting to rotate during import and export.
1°) For the moment, some client make a copy of the project, rotate it in Allplan and then make the IFC export. The problem of this method is that this will change the display of existing layout in presentation. That's the reason, it's better to do it on a copy.
2°) There is existing tool (free), which will rotate the data without changing other data. in fact the rotation is like an extra value in the IFC data.
There is one tool named "IFC Toolbox" from the buildingSmart which is available on microsoft store.
3°) There is topic of rotation, do we rotate by the origine or after have used the offset....
4°) Let's wait maybe we get improvement in the futur.
Mr Judy GURAVADU
Responsable Technique Préfabrication & Ingénierie
Precast Sales & Support
Allplan France & Allplan Software Engineering
Depuis 2006