CesiumSunSky atmosphere pop in at high elevations

[csciguy8]

Reported on the forum here...
https://community.cesium.com/t/the-problem-of-crossing-the-sky/30415

[kring]

Is this addressed by the advice in the tutorial?

(from the end of this section: https://cesium.com/learn/unreal/unreal-geospatially-accurate-sun/#sky-atmosphere-component)

[csciguy8]

Missed that snippet. Yes, that probably resolves it.

@kring , would it be worth exploring a solution where this just works "out of the box"?

Going into "space view" might be an edge case for a general Unreal user, but is probably much more common for a Cesium user.

[kring]

Well, I suppose we could set those CVars automatically. But there are consequences, described here:
https://docs.unrealengine.com/5.3/en-US/sky-atmosphere-component-in-unreal-engine/#movingfromgroundtoouterspace
I'm not aware of any better options.

[csciguy8]

Btw, I can see this pop even in our cesium-unreal-samples, Level 04, when just flying to different locations.

If I turn off those CVar optimizations, it seems to fix the pop, and oddly enough, I don't see any of the problems mentioned.

If we did want to automatically configure those CVars, we can do probably do that in CesiumSunSky here, where it is already doing some logic based on the current pawn's position.

(FYI, the pop seems to happen around a height of 70,000 meters)