Perhaps
the most important characteristic of an outdoors environment is
lighting. If you make or play computer games, you probably don't
get outside enough, but go have a look around on a bright, sunny
day. Notice how the well-lit surfaces practically glow, and there
is a large contrast between lit areas and shadows? Now go look
at most games with outdoors areas - it probably feels like it
is overcast, perhaps smoggy, doesn't it? There's a lot of different
ways to achieve the proper color for a sunlit scene, and they
include light color, the particular painting style of the textures,
and consistent shadow direction. I can't even begin to describe
all the different approaches, and different ones will work for
different projects, but I can say that if it doesn't feel like
sunlight at a gut level that means you need to keep working.
I can't
even cite a great example of an outdoor game that has good colors
and lighting - they usually fail in one way or another. Trespasser
didn't quite get the colors and contrast, and almost every "outdoors"
Unreal level I've seen takes place at night, because Unreal
doesn't offer a "sun" light by default - i.e. you can't
put a single light in your level and light everything with it. In
fact, all Unreal lights have surprisingly small areas. This
is the main reason why Unreal seems so dark all the time
- it is fairly capable of rendering large areas, but it is quite
incapable of easily lighting an entire large area with a single
light source, so you get this look of "spots of light."
We ended up hacking in an extended-range light for our game, but
this of course created other problems like certain faces of the
world geometry turning black, necessitating a lot of hard work on
individual faces to get an overall consistent look. At any rate,
if you ever intend any of your outdoor levels to take place in sunlight,
don't assume you can just throw a yellow light on them and be done.
Second most
important after achieving a sunlit look is to texture the level
well. Even if you come up with the perfect grass texture that looks
like it is lit by noon sun, you have barely begun to texture your
level. Nature is marked by continuous variation, and the large-scale
texture repetition which is acceptable for man-made areas just looks
wrong for an outdoor area. Case in point is the first level of Wheel
of Time - the geometry is fairly natural and realistic given
the limitations of the engine, but its looks are shot down when
you glance around and realize that there are three colors to the
world: grass, dirt, and the rocky hills. Unreal itself is
similar, though with even less-natural world geometry.
Unreal
is not particularly well suited to the kind of massive texture variation
needed to make grass, rock, and dirt look natural and no painted-on,
but it is possible to avoid that look. The features of Unreal
which work against this include the fact that Unreal likes
to combine the individual triangles of its world geometry into larger
continuous planes, and only allows level editors to texture to the
combined surfaces. In this particular engine, the key is to know
how to bring in geometry and maintain the original triangles. Unreal
level designers must be even more careful to watch the poly count
of their levels when doing this, but it allows texture artists free
reign to change textures as often as possible. In other, more outdoor-suited
engines, there should be ways to place and layer textures arbitrarily,
regardless of the underlying geometry.
In any
case, once the flexibility to change textures as frequently as
possible is gained, the problem becomes what the content of those
textures should be. The biggest key to natural looks is to pay
attention to edges and borders. This should seem obvious, but
when you wish to change from one texture to another, you should
use a transition that logically blends from one to another. So,
for instance, if you have a steep cliff next to a meadow, the
bottom edge of the cliff should look like a collection of rocks
and long grass, rather than just a single continous generic "rock"
texture tiled right down to the grass edge. This even applies
to man-made areas, and is one of the reason many FPS levels have
a "extruded of a solid material" look.
