Hi @hakon, thanks for your question and welcome to the forum. Cesium does not currently support per-building metadata for multiple buildings within a single model. In order to get the behavior you’re looking for, you would need to export your buildings as KML/COLLADA or CityGML. These are available as export options in many software packages. If you upload the data to ion as KML/COLLADA or CityGML, the per-building metadata will be preserved, and you’ll see it come up on click.
Let us know if you give that a try and if you encounter any further issues!
Thanks,
Matt