How can I set the opacity of the 3dTiles by Cesium for Unreal?

Hi Cesium Team,
I want to set the opacity of the 3dTiles and the TileMap, I have tried to use the function called SetMaterial in blueprint


However the CesiumTileMapServiceRasterOverlay is worked, it can be transparent what i want, but the 3dTiles buildings could not work, the editor process will be stuck. Can you give some suggestions? Thanks!