I’m new to unreal engine, I’ve used to do some small projects in blender. while I was experimenting with SkyAtmosphere, I’ve found this weird noise(black dots and noise on the atmosphere layer) while rendering earth with SkyAtmosphere. I’m working with huge scale with default ground radius and 6360 as earth radius, I’ve tried changing clipping range an many thing to get rid of it but I can’t. Any help would be appreciated, Thank You.
Hi,
When you get out of the atmosphere top boundary, we switch to a mode not using the fast Look-Up-Tables but instead per pixel tracing (because LUTs are less accurate when not inside the atmosphere). To reduce banding coming from earth shadows for instance, we jitter the ray position which results in this temporal noise pattern. TAA should eat it up completely and make the pattern invisible. My guess is maybe you have turned off TAA?
Make sure you also have a read at Sky Atmosphere | Unreal Engine Documentation, Section “Moving from Ground to Outer Space”.
Otherwise it is an unknown problem (for such simple view of the atmosphere I would expect the signal to be smooth). An expensive way (workaround) to get rid of the noise is to increase the number of sample taken when raymarching the atmosphere (TraceSampleCountScale on the SkyAtmosphere component).
I hope this helps.
Thank you so much the sample count cmd worked as intended, i wish there was option in rendering menu. And btw I’ve also go another issue with SkyAtmosphere when I set the directional light rotation to 0,0,0 then my earth gets red color I know its SkyAtmosphere issue cuz if I hide it the earth look normal color. Is there any way to fix this?
Hi,
I know the SkyAtmosphere is not simple: it has quite some options because it tries to cover many use cases while scaling form mobile to cinematic. But for space views I recommend you to read the documentation 
See: Sky Atmosphere | Unreal Engine Documentation
That is only for directional light direct lighting. Ambient/Env lighting only works for the skylight for the entire level as of today. You will have to make the best you can with that or simply disable the sky light during space view.
I forgot to answer
In 4.26, the sample count can be scale up on the SkyAtmosphere component itself. I cannot rmember the name but it hsould be easy to find. It seems that Sky Atmosphere Reference | Unreal Engine Documentation is missing that new properties! I will report.
thanks!
Not to butt in, but wondering if you have temporal anti aliasing or any form of anti aliasing enabled…
yes its enabled thank you, i found that sky atmosphere sample count is low on default
I’ve tried that **Per Pixel Atmosphere Transmittance **but there is a big visible pattern on the atmosphere like this
I believe that is because your mesh intersects the virtual planet ground, causing it to be completely shadowed. You need to either scale up your mesh, or scale down the planet ground radius.
