I’ve dived head first back into mapping for Left 4 Dead after becoming frustrated with the whole thing a few weeks ago. I came back and started the sewer sections, this time taking ages over each area. I’ve been looking over the Valve official maps, all of which have been generously made available in the game files to poke and fiddle around with. The first thing you notice opening a Valve map is how much damn detail there is in every single section.
Above: before and after a panic event is activated. A klaxon goes off, the large hexagonal doors slide slowly open and then … zombies! Except there are no zombies ’cause I haven’t hooked these areas up to the NAV yet. Another lesson from Valve maps: use fewer larger light sources. Some areas are let with two massive light_spot entities of subtly differing colours at opposing ends of a location. Also: use lots of low lights. The dev commentary that comes with L4D mentions how Valve used street cars for a lot of the lighting, giving them a good excuse to have low light sources which tend to cast more dramatic shadows. In outdoor locations it lets you leave the tops of buildings in shadow, used in combination with a sky that’s dark at the horizon and lighter overhead (as in the No Mercy campaign) you get good silhouettes which, if broken up well enough, give the impression of greater detail than is actually present.
So, back to the sewer, there are just three light sources in the above images, placed behind obstructions to generate streaks of shadow. On occasions in other maps I’ve carefully placed linvisible light occluder brushes to break up large pools of light. Textures can look dull and fake when evenly lit accross large surfaces, shadows help to break things up.
Finally a note on sewers. I often sigh when I come across yet another uninspired sewer section in a game. Along with warehouses and offices sewers are one of the most overused locations in gaming. Hammer is powerful but you’re more or less stuck with the assets you have (unless you want to spend months making a shedload of unique models), so I embraced the sewer section and tried to figure out what’s good about them. Darkness, claustrophobia, dirt rot, flickering half broken mechanics, an underworld of disrepair. The thing is, actually claustrophobic areas aren’t great in Left 4 Dead. A narrow corridor is a turkey shoot for back to back survivors, so the challenge is to create areas that are large and interesting to navigate, but which feel tight and compressed. Hopefully I can pull this off and try and push towards something close to Valve’s efforts, a lofty goal, but it’s good to aim high.