Hello everyone, I’m developing an Unreal application for my graduation project, and I’m using Cesium plugin to use the Google photorealistic 3D tileset, all i want to know is: Are there some limitations about the use of Cesium ION token and google tileset?
I mean, Can I use in my application the tileset without any limitation of use?
Hi @Vincenzo_Casillo! There’s two sets of limitations on your use of Google Photorealistic 3D Tiles. The first is Ion’s limit of 1,000 root tile requests per month, as mentioned on our pricing page. If you’re working on a project that will need to use more than that quota, you can contact our sales team to discuss a custom Ion plan.
Second, there’s Google’s limitations, which you can read about here. Lots of these rules deal with attribution, which Cesium includes a credits system to help with. Out of the box, Cesium for Unreal displays proper attribution, but if you modify the credits system you’ll need to make sure you keep with these requirements. However, Google also places restrictions on how you use the tiles, prohibiting you from using them for non-visualization use cases (such as training machine learning models) and disallowing caching and offline use. I recommend reading the documentation I’ve linked to get an idea of what the limitations are.
What do you mean for “root tile request”? What identify a request? I’m working only a specific zone of the city of Milan( about 7/8 km^2)
@Vincenzo_Casillo This is an excellent question, and we’re working on clarifying in our public material what this limitation means. Basically, a “root tile” is the base level tile - it’s the tile that all other tiles are under. When Cesium loads a location, it starts by requesting that root tile, and then works its way down the hierarchy of tiles until it figures out exactly which leaf tiles it needs to load. It only makes one request for the root tile, so it doesn’t count any differently towards your root tile quota to render part of Milan than it would to render the entire world. However, a new root tile request will be made if you reload Cesium for Unreal (for example, unloading the level, or restarting the application). You can think of it as “1,000 times initializing a scene that uses Google Photorealistic 3D Tiles per month.”
One caveat is that the token Google gives us for a root tile request only lasts three hours. So if you leave your application running for more than three hours straight, you’ll have to make another root tile request to keep receiving tiles. This isn’t currently handled automatically in Cesium for Unreal, but it should be, and we currently have an open issue about this problem: Google-compatible token refresh · Issue #749 · CesiumGS/cesium-native · GitHub. If you run into it, please let us know, as we use feedback like this to help us set our priorities!