4.16 Volumetric Fog, how to limit fog to a certain area?

Hi guys!

I’m trying to know more about the new, awesome Volumetric Fog feature that comes with 4.16 release… Great tool, but I would like to use it in a restricted area.

Let’s say: I need a cube of dense volumetric fog in my scene. The documentation about new Volumetric Fog briefly mentions how to achieve this, but I didn’t really get it… does anyone of you already played around with this new tool and figured out how to use it in the way that I mean? This is the link to the documentation, maybe you have enough knowledge to understand how to achieve this!

If you still need or anyone else then grab this “fog ball” i made based on videos from youtube. First you must have enabled “exponential height fog” and turn Volumetric ON to use this.

The issue with your solution AE_3DFX is that placing an extra fog ball doesnt remove the fog from the rest of the map that “exponential height fog” causes. I’m trying to figure this out myself now, im trying to use volumetric fog particles to create an inexpesive volumetric “space nebula” effect a player can fly through, but i only want the fog from the particle, not the rest of the exponential height component. While the settings on the exponential height fog component let me minimize the world effect, i cant disable it completely or enough to be satisfactory while still keeping particle fog volumes.

The only way I’ve found is to make the global volumetric fog on the height fog actor be VERY low, basically invisible. Then pump the volumetric scattering intensity way up on lights or bring it out with a particle or mesh, with a Volume material applied that has a very high extinction.

It’d be nice if we could somehow cancel out volumetric fog in a certain area, but volume materials can only be additive so I’m not sure there is a way.

Some cool info

Check this out: https://www.youtube.com/watch?v=Xd7-rTzfmCo

Make a material like the example on the docs page
Then assign that material to an emitter and place the emitter in the area you want to have localized fog