Starcraft AI blog

A thought while I work on more bug fixes, like the 4 bugs responsible for this absurdly bad game. (1. The enemy refinery was considered inaccessible by ground and not attacked. 2. The squad tried to take a path down the ramp which is blocked by minerals. 3. A zergling was stuck in a key position at the top of the ramp. 4. Production froze due to an undiagnosed bug which I have never seen before.)

Although an academy has zero gas cost, terran has no reason to build an academy without taking gas first, or at latest around the same time the academy is built. All uses of the academy require gas. (A refinery has half the build time of an academy, but you also have to gather some gas. The rule relies on the fact that you never want to spend that much to get 1 medic or 1 firebat.) Protoss has no reason to build a cybernetics core without taking gas first, for the same reason. These are the only 2 buildings with that property. All other buildings either require gas to be built at all, or if they have zero gas cost, they enable production that also has zero gas cost. For example, an engineering bay, forge, or evolution chamber might be used to get static defense, which costs only minerals. Zerg has no building with this property. (Imbalance!)

If you generate your own build orders automatically, you can use this as a constraint on which build orders are acceptable.