Good afternoon. I created a WebScene in ArcGIS Online and i put a BIM model inside of it, the problem is that the terrain level of ArcGIS Online, as you can see from the screenshot, is cutting my 3D model in half of the first floor. I was wondering if there was a way to know which kind of "Z-value" ArcGIS Online uses as standard, and if it was possible to assign it directly on ArcGIS Pro, in order to create the scene in a correct way, thank you.
Before publishung it into ArcGIS online you set Z coordinate systen in ArcGIS Pro. And Once it visible properly in ArcGIS Pro then publish it into ArcGIS online. I have published successfully and it's visible properly.
Yes, the accuracy of the World Elevation Surface is only as good as the underlying source data, and in many areas it is not accurate or of a low resolution.
As already suggested, the simplest solution would be to use the Adjust 3D Z tool in Desktop\Pro to move your model up and republish it. https://pro.arcgis.com/en/pro-app/latest/tool-reference/data-management/adjust-3d-z.htm
You could also look in ArcGIS Online for a more accurate ground surface for your area that has already been published by someone else and use that in your scene.
If you already have an accurate digital elevation model for the area you can publish your own elevation layers to ArcGIS Online. https://doc.arcgis.com/en/arcgis-online/manage-data/publish-elevation-layers.htm
Thank you for your advice. The problem is that using Adjust 3D Z tool in Pro does not let me select the entire Building Layer, so i'd have to do N of those Adjust 3D Z tool for every category of my BIM model, and there are many. Is there a way to match the height of the basemap with the 2D map with shapefiles i used as an input to create the entire work?
Unfortunately there is no way to modify the basemap, you either adjust your data to fit or create your own basemap.
Many of the geoprocessing tools can be run in Batch mode - just right click and choose Batch. You may still have to choose all the individual building layers but it will be quicker than running the tool many times. - https://pro.arcgis.com/en/pro-app/latest/help/analysis/geoprocessing/basics/batch-geoprocessing.htm