Exponential Height Fog doesn't display at certain angles!

Hi guys, I have a strange issue going on. I’m using an exponential height fog element in my map, but when I rotate my character’s first person camera, the fog effects seemingly disable. There’s about a 5-10 degree range where if I’m looking in that direction, the fog will stop rendering. If I stand on the spot and rotate a certain amount, the fog will become invisible, and if I keep turning, It will start to fade back into view.

Here’s an example (ignore debug text):

This is an example of “good” fog, which is enabled. The character’s YAW value is about 190 degrees here.

And here it is when I rotate to about 175 degrees, standing in the same spot. The fog magically “turns off” instantly, as soon as I cross the threshold.

What’s going on?

It looks like you have sun shaft occlusion turned on. The occlusion method for sunshafts works in a realistic manner, in that fog is only visible when it’s lit. However, currently in UE4 sunhafts are limited to screen-space, so if you aren’t facing the sun, fog is completely visible. While you are facing the sun, fog is only visible when it’s not engulfed by shadow. If you are looking to have fuller fog with sunshafts, try using the bloom method. It’s physically incorrect, but will give you more control.

Awesome, thanks so much- this completely did the trick! as you might have noticed, the sun position is behind a large mountain ridge, causing shadow to cast over the fog. Didn’t realize that this would affect the visibility. Thanks!