CesiumGS
Missing tiles with lower frame rates due to increased terrain quality and simultaneous tile loads.
What happened?
Based on what I’ve seen, reason is probably either:
- Google limiting requests or failing due to server traffic and Cesium doesn’t like that.
- Cesium failing tile memory loading, download / upload processing roadblock or hitting timeouts due to too many simultaneous loads and degraded performance.
Environment
Cesium for Unity version: Described above. Unity Editor Version: 2023.1.0f1 Operating System: Horizon OS (Android)
Reproduction steps
To reproduce:
-
Use a Unity Project with Cesium (> v1.9.1) implemented, and pull the terrain loading prevention PR I mentioned.
-
Go to New York preferably using a standalone Meta Quest 2, 3 or 3S device.
-
Use a value higher than 22 for ‘Simultaneous Tile Loads’
-
Use a value smaller than 18 for the LOD terrain detail setting, can’t remember the exact name but it was something like “pixel error” ?
-
Navigate around at ground level in Central Park near the skyscrapers and onto the streets while always letting everything load. (don’t puke on the low frame rates)
My app uses less expensive values and the issue occurred in roughly less than 1 minute after startup. I really can’t remember if the issue was deterministic or if it doesn’t happen at all sometimes, that could’ve indicated if it was an Google API issue.
Supporting evidence
Forgot to take screenshots. Just picture missing Photorealistic 3D Tiles, appearing and disappearing as you get closer or further away.
Found the log: [2025-11-14 21:21:17.048] [error] [TilesetJsonLoader.cpp:893] Received status code 503 for tile content https://tile.googleapis.com/v1/3dtiles/datasets/CgIYAQ/files/AJVsH2xQuNBpHgUP96IiX-gXe4aH84r73MTpWQR94EzKLbvwIY1WIq7cbjGJFs_NBW19We7b3CvCP9BkpMEd32ywJISGH4tfNn6LjEvcE2AezWJrdh_xA0PKKjuZiZboaEorL5KEvsrL.glb?session=CKri7uLm37Hx2QEQ2fLeyAY&key=AIzaSyDYrg6sSYSjQp4MVhsVtnW5XMCSkHFbIEc
Just in case this is a timeout, if there are any timeout values somewhere within Cesium for Unity or Native’s code please let me know.
Or [2025-11-15 17:45:14.318] [error] [TilesetContentManager.cpp:997] An unexpected error occurs when loading tile: Request for https://tile.googleapis.com/v1/3dtiles/datasets/CgIYAQ/files/AJVsH2yfIxIHoMYC2yFN8nyR1Gtx4-HJer4pYPc2HCXutBBkpWVFNA_NI-FMPzIht6DqeyZ4Vmli_yw-j1Gf3o1ESIGSfPoyn5FRqJpPuQIyA_ymQwEwJtiMxPoOszDOfw.glb?session=CK30hdqmvMGFRxDrr-PIBg&key=AIzaSyDYrg6sSYSjQp4MVhsVtnW5XMCSkHFbIEc failed: Unable to complete SSL connection
FOUND THE LOG!
Unfortunately it got deleted from the console but I believe it had a tile URL with error code 503