At use big maps I’m using here 8x8km map but note from the mountain to the camera is between 1km to 4km the height fog create the sun effect here when there are no sun, cause clearly there is the mountain.
Related with the Exponential Height Fog and the sun collision or not in the camera, note the setting are the default ones and the map is the Landscape sample Epic demo map with other landscape with different heightmap but same settings.
First of All use the Learn Tab → Landscape Mountains make sure you’r using the both in the version 4.12.x(5)
Second open the map and make a clone and save with the name you want, now in that map remove the landscape, and set all lights to total dynamic.(Directional and Skylight)
Now in the directional settings set the max of dynamic cascade shadows and max activate and set too the max of far cascade shadows.
Until here this setup apply to my 2 reports, but now is different.
Now in the AtmosphericFog2 make sure you disable it changing the fog value multiplicator to 0.0.
After that add to the scene a ExponentialHeightFog down it until you see it fit more or less in the map with the bottom of the mountains of the new landscape, now go to the middle or the bottom look to the face of the mountain that occlude the sun and you will notice this bug that pretend to be affected by the sun, when there are no sun cause is occluded.
What you’re seeing in this looks like settings for your Start Distance and Fog Height Falloff having values that aren’t set properly. I don’t think there is a bug here but I’m happy to help off some tips. Can you please post your settings you’re using for your Exponential Height Fog.
As for the other post that I marked as a duplicate. I don’t see anything necessarily in that one that is a bug as well, but you’ve not really provided enough information. It’s been re-opened, but please post the information needed to reproduce and then I can provide some tips for you to proceed.
The issue you’re likely going to see is that using large scales for all of these don’t necessarily work well. You run into precision issues and limitations the larger the world is.
To proceed I’ll need the following information:
Your Directional and skylight settings
Any fog settings adjusted (Exponential and Atmospheric)
Any additional details that are needed to look into this
So on this one, what I see here is part of how Exponential Height Fog works.
The start distance is a key factor here since this determines where the exponential height fog starts from the camera.
As I mentioned with the Atmospheric Fog issue you reported as well, this would be a good time to adjust some settings and get familiar with the settings that are available to see how the work and function together.
