I would like to add a number of raster datasets to an ArcGIS Online web scene, including a LiDAR DEM, a hillshade derived from it, and some aerial photography. ArcGIS Online does not support uploading any of the most common raster formats (e.g., tif), but does support rasters formatted as kml. Using the Layer to KML tool in ArcMap, I converted several of the raster datasets. They upload to ArcGIS online just fine and can be viewed or added as layers in the Map Viewer (2D). However, kml is not supported as a format in the 3D Scene Viewer as pointed out by Russ below.
I have also tried publishing the layers as Tile Layer Services without much luck. The rasters appear to upload fine, are recognized as data sources and preview at the correct extent and location in Web Scenes, but completely crash ArcGIS online and never load if added as a layer. They are in WGS 1984, which should be supported in global scenes and the files are not very large.
The source files (raster layers in file geodatabase) load and display correctly in normal offline ArcGIS Pro scenes and support use as elevation surfaces. So I'm not sure where the disconnect is when adding them to the online platform.
How do I add raster data to an ArcGIS online Web Scene?
I'm open to using any format or upload method that has worked for others, especially if they enable use as elevation surfaces in Web Scenes.