You are sharing a web scene or web scene layer that has extruded features. Extrusion is only supported when the features are polygons that are extruded by the base height using an Arcade expression to ArcGIS Online and ArcGIS Enterprise 10.6 and later. Either your extrusion type is not supported, or your active portal does not support extrusion and the features will be flattened.
Solutions
- Do nothing. The features will be flattened and your web scene or web scene layer will be shared.
- Convert the layer to multipatch features using the ArcGIS 3D Analyst extension Layer 3D To Feature Class tool.
More information
Some 3D display properties, such as certain extrusions, are not supported when sharing a web scene or web scene layer. To avoid flattened features, convert your 3D display properties to multipatch features.