Clamp extruded polygons to ground - Inconsistent behaviour

I am trying to clamp some extruded polygons to the ground. However, there seems to be an inconsistent behaviour for two different locations.

See this sandcastle.

In London (location 1) I have to use RELATIVE_TO_GROUND because CLAMP_TO_GROUND makes the building disappear

In San Francisco (location 2) I have to use CLAMP_TO_GROUND because with RELATIVE_TO_GROUND the buiding floats.

Am I missing something?

Has anyone else experienced this issue? I could of course hard code a check, but I would lilke to understand if I am doing something wrong.


In case it helps someone else, I had not noticed the height parameter in the polygon definition.


heightReference: Cesium.HeightReference.CLAMP_TO_GROUND


extrudedHeightReference: Cesium.HeightReference.RELATIVE_TO_GROUND

solves the problem.