When I publish a web scene from ArcGIS Pro to ArcGIS Online for use in a cityengine 3d web scene, all of my surfaces that I have custom elevations assigned to come out flat. As far as I can tell the only elevation data that the 3d webscene will read or apply, is the built in esri elevation data.
I'm trying to display subsurface geologic data.
Sharing what I've learned so far, the easiest way to accomplish this is run the tool Export to 3D Web Scene in 3D Analyst Tools/CityEngine.
There are some limitations and specifics to know about although explained here.
Here is the result of my work.
The labels are 3D points with 3D character symbology.
I created a point feature class with a letter and a depth field. I placed each point by hand, guessing on spacing, in x,y space. Then I symbolized by the letter field with a 3D character marker symbol of the letter and rotated each one along the Y axis.
Then with the depth field I used that as the base height expression for the z space.
Hope that helps.