Issue detected : You receive the following error when you try to export or synchronize your ARCHICAD file with Twinmotion :
Cause of the issue : You probably have items in your ARCHICAD project that are set on a "MISSING" layer.
How to solve it : You have to reset these items to an existing layer. To find these items, use the "Find and Select" tool from the Edit menu and add the "Model View > Attributes" option set on "are" missing. We suggest to do it from the 3D view with all the layers displayed.
If it doesn't work, please also refer to this article.