cacheBytes
The amount of GPU memory (in bytes) used to cache tiles. This memory usage is estimated from geometry, textures, and batch table textures of loaded tiles. For point clouds, this value also includes per-point metadata.
Tiles not in view are unloaded to enforce this.
If decreasing this value results in unloading tiles, the tiles are unloaded the next frame.
If tiles sized more than cacheBytes are needed to meet the desired screen space error, determined by Cesium3DTileset.maximumScreenSpaceError, for the current view, then the memory usage of the tiles loaded will exceed cacheBytes by up to maximumCacheOverflowBytes. For example, if cacheBytes is 500000, but 600000 bytes of tiles are needed to meet the screen space error, then 600000 bytes of tiles may be loaded (if maximumCacheOverflowBytes is at least 100000). When these tiles go out of view, they will be unloaded.