Starcraft AI blog

Back when I played online regularly, one of the tricks I pulled sometimes was to build an expansion hatchery out of position, where it might escape being scouted. Main bases on many maps have space behind the gas geyser, and if the geyser is on the opposite side from the base entrance, I might put a hatchery there and mine gas and the edge minerals. Some maps, like Python, have space behind the minerals where a hatchery can go. If the base was defensible, I could add another hatchery in the usual position later.

Another reason to build out of position is that the position is blocked, for example by a pylon or a spider mine. Terran can build an offset command center and float it into place after the block is removed. Even zerg will sometimes build a hatchery in an offset position, especially if the expansion is desperately needed. (I don’t think I’ve seen a deliberately offset nexus in pro play. That’s a bigger investment.)

These tricks came to mind because Steamhammer doesn’t support them. I’ve been working on the base placement code, which assumes without question that there is One Correct Placement. It’s much easier to to code that way, and the results are good—special tricks are for special circumstances, not for most games.

Still, the thought reminded me again that bots need to be more flexible in their thinking. Placing a base should be like tactical analysis in that it considers different actions (at least in unusual situations) and compares them to choose the best.