Q: How can I achieve the effect of selecting units of different floors?

A: To achieve the effect of selecting units of different floors, you need the vector regions for each floor. For a building of 5 floors with the bottom altitude at 0 meters and the height of 3 meters for each floor, you need 5 overlapping regions for all the 5 floors. You should create two fields to store the bottom altitude and extruded height respectively. For the 1st floor, set the bottom altitude to 0 and extruded height to 3. For the 2nd floor, set the bottom altitude to 3 and extruded height to 3. You need to set values for the two fields for all the 5 regions for the 5 floors and add the data to the scene. After that, set the Altitude Mode to Relative to Ground, set Bottom Altitude and Extension to the corresponding fields. Finally, check Clamp to object while setting the Layer Selection Style for the layer.