I may be doing something completely wrong here, but I did follow your tutorial here:
Clipping Tilesets – Cesium
But when I try to clip out a section of a tile that is of any shape, it will remove the whole section of the tile.
My settings appear to be correct, unless this is the part I am misunderstanding.
Am I being stupid and missing something obvious here?
I’m using Cesium for Unreal v1.31.0 downloaded from GitHub with version 5.2.1 of Unreal Engine.
(Edited to use correct settings image.)