In 4.0 Beta 1, a polygon on FeatureLayer can be 3D using 3D symbol (PolygonSymbol3D).
However the rooftop of 3D polygon is not horizontal when the elevationInfo.mode is "onTheGround" or "relativeToGround".
And using "absoluteHeight" mode, 3D polygon is a horizontal rooftop but buried in the surface of 3D map.
3D polygon in "onTheGround"
3D polygon in "absoluteHeight"
Is it possible to create a horizontal rooftop in "onTheGround" or "relativeToGround" mode?
FYI, in ArcGIS Runtime SDK for .NET version 10.2.6, it can be by the Maximum mode of ExtrusionMode Enumeration.
Red: BaseHeight mode
Green: Maximum mode