I see the function for classifying 3d tilesets using textured ground primitives, which is fine for small images but would fail for large area classification with textured primitives.
2. A minimal code example. If you've found a bug, this helps us reproduce and repair it.
3. Context. Why do you need to do this? We might know a better way to accomplish your goal.
Draping imagery layers on 3d tilesets without initial textures (e.g. a TIN created from point grids).
4. The Cesium version you're using, your operating system and browser.