Starcraft AI blog

In a game Steamhammer - McRaveZ on La Mancha, McRave pulled drones to try to survive.

But what happened to that one drone that seems to be leaning over the chasm? It collided with other units and was pushed across unwalkable terrain to a new position where it was trapped.

Steamhammer’s zerglings desperately want to get at that drone, but they can’t... quite... reach it. The zerglings were nearly useless for the rest of the game, distracted by the stuck drone every time they reached the enemy base. Steamhammer floundered until it finally remembered that mutalisks are also a unit it can make.

Here is the walkability map. Steamhammer actually checks that it can reach the drone target, but the check is incorrect in this case: There is a narrow corridor, one walk tile or 8 pixels across, leading to the little platform where the drone waits. No unit is narrow enough to walk there (even a ghost is 15 pixels wide), but Steamhammer doesn’t know that.

The imprisoned drone illustrates a flaw in the map design: Accidents should not push units into places where they will be permanently trapped. Freakling would never allow such a blunder! Of course it also illustrates a bug in Steamhammer. The bug makes a regular appearance on a few maps, like Fortress, but this is the first time I’ve seen it affect play on a regular SSCAIT map.

Next: Steamhammer status. Soon: Some of Steamhammer’s best recent games.