Just a quick post while I have some form of web access (I’ll be back late next week when normal service shall resume).
I think one of the greatest things that helped me work out the intricacies of mapping was to really study what other people were doing. Simply running around maps I liked (but ideally had only played a few times), looking at all the bits that I didn’t usually have the time to look at and analyse. The important question was then to ask why the map was built as it was - why particular textures were chosen, why the layout and colours are as they are. Basically, questioning why everything is the way it is and thinking how else it could be done.
This was particularly important while I was making ETC and ETC 2. Being able to get the feeling of particular parts of HL1 required really looking into the details behind some of its level design, primarily for design cues and aesthetics. Knowing about the details of a particular theme is key to recreating the feel of the original game - it’s not just about slapping on a couple of ‘lab’ textures, scientists and telling players it’s the same part of the game as the resonance cascade.
The best way is to just take screenshots. Hundreds. I did this when I made Dust PCG, to make sure I got the CS:S Dust theme as accurate as possible, otherwise it would have looked a complete mess. If you ever think about creating a level in a particular style, always make sure you have some reference, or you end up with something like de_dust2000 which shares a name and texture set with Dust, but none of the style.
Actually, doing this taught me a few suprising things while I was making ETC 2. In particular, in some parts of HL1, overhead pipes and details use very bizarre texture choices, or some that you just wouldn’t expect. In Hammer, they look a bit strange, but once in-game, they tend to fit very well. It occured to me that the weird texture choice was not due to laziness (not using the ‘proper’ texture) or anything like that, it was simply because the texture choice helped keep the pipes in the background, as a background element of the game. While the pipes could have been accentuated with proper texturing, that would have simply taken a bit of attention away from something else. But ultimately it taught me one thing: just because a texture has ‘floor’ or ‘ceil’ in the name does not mean it won’t work on a wall.
It’s a very simple, silly lesson, but treating the palette as a toy for experimentation, rather than thinking of each texture as being restricted to particular uses, really helps give you the freedom to create. And that is very important.