I recently asked a question to a pro expert about some issues I was having exporting procedural symbols to Web Scene, and the answer is you cannot export procedural symbols to webscene, you first must bake the geometry. See Answer below.
Workflow Outline is based on a reply from Chris Wilkins.
First, you cannot directly use procedural symbols in a web scene. You must use FFCER or L3D2FC GP tools, to bake (or cook) geometry to a multipatch feature class (or layer).
Then with that MP layer, you must use create and share using SPK (scene layer package). This is only because it is 3D.
Layer 3D To Feature Class—Help | ArcGIS for Desktop
Which leads you to this GP tool:
And then you must use Share Package GP tool:
THEN, you must go to AGOL to hit the share/publish button.
THEN, you must create a web scene and add the scene layer.
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