Atmospheric fog + directional light = red ground, black sky

When I drag the atmospheric fog into a blank scene along with a directional light, all it does it make a red ground-plane and a black sky. When I rotate the fog, the floor changes color, but doesn’t seem to interact with the directional to create any kind of atmosphere above the horizon:

I’m on Mac OS 10.10.1, running an NVidia GeForce GTX 680/4K: I’ve read people attributing this to a problem with the Mac OS, but the weird thing is, the atmospheric fog and directional light behave normally in the Content Starter scenes (so I guess that presumably also rules out any rendering issues?). When I try to copy them from there and paste them into blank scenes, they stop working. Sky light also seems to have no effect.

Things I’ve tried to fix this, which did not work:

  • switching from 5.6 to 5.5
  • switching from the NVidia Web Drivers to the native Mac OS drivers
  • someone said to play with the “recompute params” numbers
  • playing with every value and switch in both the atmospheric fog and directional light details
  • cranking the scene quality to Epic
  • rebuilding after trying anything

All nothing. Soooo, yeah. I don’t know - I’m not really sure how to troubleshoot beyond this: I’m still pretty new to Unreal and I’m not sure where else to look for answers inside the system. Normally, I’d probably chock this up to being a rendering problem, but the fact that everything works fine in the demo scenes makes me think that this might be fixable…? Any ideas? Thanks…!

Edit: I’ve been messing around in the demo scenes where the atmospheric fog and directional light are working together correctly, and it’s actually the same here, too. They work in tandem perfectly, but if I copy one, delete it, then paste it back in, the fog and the light seem to cease interacting. I’ve also noticed that when I delete the directional light in this scene, the remaining fog still has a beautiful glowing quality to it: once the fog is deleted then brought back, it loses all of this quality, and just looks like a blob on the ground.

Edit: oh, so this works fine in the current preview of 4.7! Cool cool. Sooo, I guess that means it was a bug in 4.5/4.6…?

Hi,

The problem you’re seeing here is just that I think there is some confusion about how these are setup in the default scene vs setting these up from scratch.

By default the Atmospheric fog, Directional Light, and other components don’t work in tandem. They need to be properly setup to do so. For instance, in the default scene The sky sphere is actually a Blueprint (BP_Sky_Sphere) that has a sky dome, atmospheric fog and bunch of other parameters setup. The directional light is tied into this via the details panel where you can use drop down selector to get the directional light from the scene.

I hope this helps clarify some of the frustration and confusion you’ve had regarding this. :slight_smile:

Tim

Hi Tim, thanks. So, you’re saying that the directional light needs to be piped into the atmospheric fog manually, in order for this effect to display correctly? I’m afraid I don’t see any drop-down in the atmospheric fog where the directional shows up, could you be more specific? Strangely, the demo I was drawing from simply dragged-and-dropped the atmospheric fog, and it worked out of the box, as it seems to in 4.7. Additionally, I don’t see anything about setting up this connection in the user guide’s section on it…? Anyway, thanks!

Oh - yeah, sorry, I should’ve mentioned I tried that one. It changes the color of the ground, and the placement of the sun disk, but doesn’t add an atmosphere, even after the lighting’s been rebuilt. Is there something else I could be missing? Thanks, Tim.

The atmospheric fog includes a “sun disc” but this is not a light source. It is just a visual representation of the sun. The Directional light is the light source but does not have a visual representation.

Ignore part of what I said about the BP_Sky_Sphere. The setting I referred to for the directional light was located in the details panel for this blueprint. :slight_smile:

In your blank scene place the directional light and the atmosphere fog. Select the directional light and check the box labeled Atmosphere Sun Light. This will sync those two together.

Let me know if that works for you.

Tim

Not that I’m seeing. I know you mentioned you’re on a Mac, which I can test. I don’t have access to one right now, but I’ll see if I can set this up and see if I get the same results like that.

With that setup on Windows mine works perfectly every time. I’ll get back to you soon with my results.

There was a bug in Atmospheric Fog on OS X and that has been fixed for 4.7.

Not to threadjack but I was working with an atmospheric fog (playing with some of the defaults) and all the sudden the whole sky turned black like this and won’t go back to normal even after resetting all the values to default.

I’m on PC.

Any idea why this might be happened or how I might fix it?

Thanks,

ook