No content when using »Import Resources...«
VectorWorks 12 provides a new feature to ask it for resources which are placed in the folder ./Libraries/ of the VectorWorks installation. The brand new resource importer provided by interiorCAD 3 only works if this VectorWorks 12 feature is switched on. Otherwise no resources will appear in the resource importer of interiorCAD.
In the VectorWorks preferences, please ensure the option »Display Default Content« is enabled:

