We were having some issues with pawn during movement stuff while standing on top of the 3DTileset object. Changing TickGroup to PrePhysics fixes the problem for us, so we just want to understand what issues we might see with Cesium because of this change. Thanks.
If I recall correctly, the reason is that the camera movements for a given frame are evaluated during the Physics tick group. We need the final camera position for the frame during the 3D Tile selection algorithm that takes place during the Cesium3DTileset Tick. If you put the tileset tick before the camera movement, you may see an increase in missing tiles on the corner of your screen when panning or zooming out. This happens since the tile selection algorithm is one frame behind.
If you need to put the tileset in an earlier tick group, you may want to try unchecking “Enable Frustum Culling” on the tileset actor’s details panel. Unreal Engine will continue to perform renderer-level frustum culling, but the tile selection algorithm will continue to load off-screen tiles. This will get rid of the missing tiles on the corner of the screen, but tilesets will load slower overall since more tiles will be requested.