I have spent a full day messing around with this to try to create a tool for planning purposes. I am continuing to get errors on my layers "unsupported elevation setting" even though both are set to on ground, which is supported when I looked into error 00236 fixes.
Also, it is apparently impossible to overwrite a 3D scene, so the number of times I've retyped metadata to the point where i gave up is mind numbing.
If anyone has best practices workflow on how to get 3D simple shapes into a web app, please advice. I also tried a work around by publishing 3D from 2D as a weblayer, which didn't work. I can't share a weblayer from pro arc scene, so I'm not really clear on whether to bother trying to utilize 3D shapefiles from arcmap pro in an online environment - or if I should be publishing 2D with Z values and then using something online to build those up into basic shapes.