Fog Rings
Or, How to remove pop-up on large maps.
Fog rings are basically ring-shaped static meshes that you place
inside your skybox. They start with a solid color at the bottom,
and fade out into transparency at the top. They can be used to add
depth, or just for decoration, but their main use is to hide pop-up
in large maps. It basically fakes fog in the skybox.
When creating a large map, such as an Onslaught map, the editor
will only render a certain distance before chopping off the distance.
This draw-distance is a limitation of the editor and cannot be changed.
This can be hidden however, by using fog throughout the level the
same color as the fog ring. The architecture/terrain will fade to
the fog color at a distance, and once faded, won't be visible in
front of the fog ring. So when it does become chopped off in-game,
it will not be visible to the player.
The minor draw-back is that no detail can be placed in the bottom
half of the skybox, so if a player flies high, or is in a location
where a lot of the vertical skybox should be seen, the bottom half
of the skybox is a dull, solid, color. The height of the fog-ring
will depend on how high you build your level. Generally the higher
your architecture, the higher your fog-ring must be in order to
hide the pop up.
Finding and Using a Fog Ring...
First of all build you skybox using the textures you want to use.
Do not add too much detail in the lower area of your skybox as of
yet, as you may find your fog ring will hide much of this detail.
Next, we need to find a fog ring to match your skybox. Fog-rings
are quite scarce for UT2K4, here are a few static mesh packages
that I've found them in, along with their relevant colors (More
added as I locate them).
BarrenHardware-epic, under Decos > egypt (Sand/Peach)
CP_Nightmare_1-epic, under Arches (Red)
A quick and easy way to find a fog ring is to paste one from another
official map. This practice isn't encouraged, but if you have to,
here is some fog rings...
ONS-Dawn (Grey)
ONS-FrostBite (Plum)
ONS-Torlan (Light Orange)
ONS-Dria (Dark Blue)
ONS-Tricky (Brown)
ONS-RedPlanet (Red)
ONS-Surripere (Blue)
The next step is to place your fog ring into your skybox, resizing
it as necessary If you copied one, paste it in. If you found one,
select the fog ring inside the static mesh window by clicking it
once, then right-click the ground anywhere in your level and click
"Add static mesh...". Your fog ring should appear before
your very eyes. If you don't see it, try to locate it using your
2D views.
Next, using your 2D views, move the fog ring into your skybox.
It should be vertically centered, at roughly the same level as your
skybox info actor. It may help to adjust it whilst viewing the sky
from within your level. You may need to resize it to fit - use the
boxes at the bottom of the editor to change the values to change
the size of your skybox as you see fit, as shown in the image below.

For the vertical size, the fog ring should be high enough so that
it hides all pop up in your level, and low enough so that the player
cannot see beneath it. The width of the ring isn't too important,
so long as it is centered. You should end up with a result similar
to the image above. If you can't get the lower half covered, you
can duplicate the fogring, turn it upside-down, and join them. A
quick was to do this is to put a minus value into your DrawScale3D.
Fog Rings can be darkened/brightened by changing their Unlit value
to false, and altering the AmbientGlow value (Both can be found
in: Properties > Display). If you can't find a fog-ring to suit
your map, you can always create your own custom shader to apply
to the mesh, by importing your texture and changing the fog ring's
skin (Also located in Properties > Display).
Adding Fog
Next, in your 3D view, locate your Zone Info actor for your outdoor
areas. If you don't have any ZoneInfo actors in your map yet, now
is the time to add them. If you do, skip the next step.
ZoneInfo actors set individual properties, such as fog color and
density, for designated areas, or 'zones'. If you don't split your
level into zones, your entire level will be one 'zone', and you
will only need one ZoneInfo actor. This tutorial won't go into zones,
and what they are used for. You do not need to know about zones
to complete this tutorial, however you may wish to look this up
yourself.
Adding a ZoneInfo Actor:
Open your actor browser (Chess piece button) and expand Info, and
click ZoneInfo once to highlight it. In your 3D view, right-click
the ground anywhere and click "Add ZoneInfo". An icon
similar to the skybox info should appear. You do not need to reposition
this, although you may wish to reposition this in a visible place
so you can find it should you want to get back to it.

Next, double-click your ZoneInfo actor to open it's properties.
It's worth rebuilding all at this point, so that you will be able
to see the changes in the fog you apply in the next step (Shortcut:
F8).
Change fog color and distances inside the properties using the
options shown in the image below. The fog color should be exactly
the same as the color of the fog ring. The DistanceFogStart and
DistanceFogEnd should be self explanatory; the end value is the
distance where the architecture is invisible.

You should now see no or very little pop-up in your map. All that
is left for you to do is tweak the fogging and your skybox to your
liking. |