Hint brushes won't magically reduce your polygon count, but they can help if you know how to use them. The key things are:
- Avoid open areas.
- Don't make too much detail visible at once.
They both go together, to a degree. If you have an open area with lots of detail, it's all going to be visible at once. In addition to that, quake2 compilers break the map up at certain intervals, so even if you have a plain room with no detail, a small room will have fewer polygons than a large room, because the large room will be broken up into smaller polygons (this was necessary for the software renderer, I think). If you need large areas, you can reduce the chopping by scaling the textures up. If you have a big room 4x's the size of a smaller room and scale the textures up 4x's as big, the polygon breakup will be the same.
Reducing detail in a given area is a whole different beast. It's really best to sketch out a design of your map and plan different areas. You want to make each area of the map have as little possible visible to other areas. One method for this is called "snaking", which you can see in brainstorm.bsp -- it looks like a large, outdoor area, but only small sections are visible at any given time. Another method is the big 'ol "vis blockers" seen in the battle maps. I don't care for these much, unless you can make them look natural. Finally, there's the simple "rooms with doors" approach. And of course, any mixing and matching of the methods. Whatever you do, make sure you offer plenty of routes into and out of the bases to keep the gameplay interesting.
