Why Did Ultima Online's Living Ecology Collapse When Players Arrived?

Start with the legend, because your readers already know it. In the version usually told, Origin built a virtual ecology for Ultima Online, players poured in and killed everything faster than the game could spawn it, and the designers ripped the system out in sadness. Richard Garriott has been quoted in that spirit, saying the players killed everything so fast that the simulation could not even begin, and that nobody ever noticed the system. According to the person who designed the system, it is not quite what happened. Koster wrote a correction post because anecdote-based articles kept getting this wrong. He states two separate facts the legend merges into one: the AI was disabled because of the cost of radial searches followed by pathfinding, which had nothing to do with why the ecology collapsed; and the ecology collapsed because of a closed economy loop in which everything spawned from a fixed resource pool, which fell victim to player hoarding.

The system, conceived by Koster and his wife Kristen in early 1995, gave every object resource tags. A creature could PRODUCE things, EAT things up to a stomach size in bites of a given size, SHELTER near things it liked, and DESIRE things it wanted or feared, satisfying FOOD first, then SHELTER, then DESIRES. Spawning worked from surplus: plenty of GRASS spawned GRASS-eaters, and their MEAT then spawned MEAT-eaters. The famous pre-release example said that if adventurers thinned the rabbits, wolves would move on to deer, and a hungry dragon might then wander toward a village. In alpha, animals also levelled up like players, which produced the case's best joke: rabbits that survived a wolf fight got tougher, so players who let bunnies escape trained killer rabbits. The Game Developer report of the 2012 postmortem quotes Koster joking that alpha players soon found themselves playing Monty Python: The MMO, and that the team stopped the levelling but left one monster rabbit in the shipped world. That anecdote is real, and it is also small.

The first failure was performance, and it hit before players could do anything. Koster writes that the creature AI worked in alpha: beggars with a desire for GOLD followed rich players, and bears hung around near beehives. The problem was that the constant radial searches were incredibly expensive, and so was all the pathfinding. The team cut search frequency, then took a step Koster says alone really ruins the large-scale ecological applications completely: every creature was put to sleep when players were not nearby. A simulation that only runs while watched is not a world ecology anymore. The system was also rewritten during beta by an engineer who, in Koster's words, did not really like or understand it, and the planned second stage, hooking the ecology into quests, never happened. Spawn regions, which placed creatures by drawn areas and lists instead of by resource surplus, eventually took over all spawning.

The second failure was the closed bank, and this is where players genuinely broke something. In the original design, new objects were withdrawn from a resource bank: a fixed pool of each resource. When the bank was overdrawn of MEAT, nothing using MEAT could spawn until some MEAT was destroyed and returned to it. In practice, Koster says, it was not MEAT that stopped creatures spawning. It was FUR and similar goods that players hoarded, which prevented deer and rabbits from returning. His correction post gives the cleanest example: players killed sheep, made huge numbers of shirts from the wool to grind crafting advancement, then hoarded the shirts or sold them very slowly. The central bank ran out of wool and could not spawn more sheep. The players did not eat the ecology by killing too fast. They starved it by keeping too much: shirts sitting in banks and houses were wool that would never come back, so the world could not make the animal that wool came from.

None of the steps below are presented as what Origin did, because Origin did not do them. They are the design rules that follow from Koster's account of what went wrong, rewritten for a small team building a simulated world today, and they stay inside your own project: nothing here asks you to touch a live game, a public server, or anyone else economy. A simulated ecology has three budgets, not one: the processor budget for noticing the world, the material budget for making things, and the player budget for keeping things. Ultima Online ran out of all three, in that order, and the legend only remembers the third.