This release Cesium Releases in February 2023 – Cesium mentions new procedurally generated windows but I cannot find any information about this other than this post. Can someone tell me how to turn this on?
Take a look at the Cesium for Unreal Samples project, which can be obtained from GitHub (GitHub - CesiumGS/cesium-unreal-samples: Getting Started Sample Project for Cesium for Unreal) or from the Epic Marketplace. Level 10 demonstrates and explains the new feature.