[RESOLVED] Issue with Cesium Sun Sky hiding Earth surface

Hi there!

I am using Cesium in UE4 and I noticed that when I change the SolarTime variable in the CesiumSunSky blueprint, the other half of the world (which was previously in darkness), is now covered by atmosphere and just shows a blue ball, rather than the usual Cesium atmosphere and terrain. Although this is what I see when I play in the editor, it remains a problem when I run the program externally.

I have tried to play around with the properties of the Cesium Sun Sky blueprint but with no luck. I have attached two images to this post. One is what the Earth looks like using the default settings and the second is what the Earth looks like when I change the SolarTime by 12 hours.

Any help on this would be greatly appreciated.


Fixed the issue by changing the Transmittance Minimum Angle in the SkyAtmosphere component of CesiumSunSky from -90 to 90 degrees. Not completely sure what the side-effects of this change will be, but it allows the entire globe to be seen regardless of position of the sun.


Hope this helps someone!


Hi @harrisonv789

Thanks for finding this problem! This is definitely unwanted behavior, and I’ve created an issue for it in the github repository - SkyAtmosphere sometimes hides earth's surface · Issue #527 · CesiumGS/cesium-unreal · GitHub

I did some testing and it looks like it happens to the rest of the world whenever the sun sets on the Georeference Origin. The fix you found does seem to resolve it, but we’ll need to do some testing to make sure it doesn’t cause any unintended side effects before integrating it into the plugin.