I was trying to implement a feature that is to flat the overlap area between a polygon and a 3D tiles to a given height but didn’t make it.
Cesium provides the clipping plane feature to trim the 3D Tiles which is very much similar to what I want to implement. The difference is that the clipping discards all the vertex but in my case, I want all the vertexes to be set in the same z value.
Therefore, I tried to modify the z value of there discarded fragment in the clipping shader. However, many errors came up with any of the changes I made.