Hello @kientegadesire4​, FME will always write Cesium 3D Tiles in EPSG:4978 -> WGS84 geocentric. This is handled by the writer itself, so it is necessary to have a coordinate system set on the features being translated, so the writer knows how to reproject them accordingly. My hunch is that the writer couldn't determine a source coordinate system for the features and was unable to properly reproject. To set a coordinate system on the IFC features:

1. Specify the IFC File's coordinate system on the Reader feature type
2. Use a CoordinateSystemSetter to assign the appropriate coordinate system

If you're still experiencing issues, please consider sharing a sample dataset or workspace! Happy to help, Kailin.

Hello @kailinatsafe​ , thank you for your suggestion! But i still having issues.

here is my workspace, and the IFC.

Need help!!

Hello @kientegadesire4​, thanks for sharing the data and workspace! I see that we've set EPSG:4978 as the reader coordinate system, as well as in CoordinateSystemSetter. This is technically incorrect, as this is not the source coordinate system for your IFC data, this is the coordinate system the Cesium Tiles Writer will automatically reproject too at runtime.

After some testing, I had the most luck with letting the workspace handle the coordinate system conversion entirely (eg. removing all references to the coordinate system in the workspace. This included: removing the CS set on the reader and writer, and deleting the CoordinateSystemSetter). Sorry if I initially mislead you there!

You'll notice the Tester is used to remove the IfcSite feature type from the model, it looked like it was simply storing terrain or a base, not sure this is required. The output in cesiumION:

Reminder: If you're writing to Cesium Tiles, there really is no point to reprojecting in the workspace, because the Cesium Tiles Writer only supports one Coordinate system (EPSG:4978). Please let me know if you have any further questions! Hope this helps, Kailin

Thank YOU!!!