Hi @yangcumtb,
Thanks for your post.
Can you please share some sample code so we can see your approach so far? That will make it easier for us to recommend the best approach depending on your use case.
This issue may be relevant to your question How? RectangleGeometry extrudedHeight gradient ramp Color Material bottom-up (floor-sky) · Issue #9285 · CesiumGS/cesium · GitHub. But again sharing sample code showing your current approach will help us provide specific feedback.
Thanks!
Luke