Should you have to save back to 16, you'll need 18 and 17 as well and 'save as...' from 19 > 18 > 17 > 16 and deal with the pain of no building materials as probably the biggest challenge.
Are they to work with you on the architectural model? Or are they providing some other sort of work? I'm wondering if IFC might be better to just share the model.
Erwin Edel, Project Lead, Leloup Architecten
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