Hey all, I’m back with the second in a series of posts about something that’s been around for ages for this week’s Video Game Tuesday. It’s all about part two of my blog on the use of artificial intelligence, or AI, in video games.

So, last time I talked about AI in general and some of things that it did to make video games actually possible. This week I’m going to be going over some more fundamental stuff, namely pathfinding. Pathfinding, or as some call it the Monte Carlo Tree Search method, is something that most games need that sometimes gets done badly.

Tree search method?: That term is a reference to a programming tree of actions and responses to an input, basically a series of if/then statements applied to the coding in a game. Say a player is facing an enemy, and they choose to jump. It might go something like this, “Did a player jump?” If Yes – then “Did a player jump before an attack was launched?” If Yes then…etc. This string of logical questions lets the system decide what to do next in certain situations. This most often comes into play for pathfinding in games.

Take for example Assassin’s Creed where a player is detected in a restricted zone, and the enemies become all hostile, alert, and begin looking for them. The enemies can often jump down a bit, go down a ladder, or up a set of stairs to look around for the player. But at no point can they decide to start walking in midair to reach a player or move directly to where they are without discovering them.

That’s what I mean by pathfinding. It’s a highly complex set of programming, and most players don’t really appreciate how much work goes into making good and solid pathfinding that can handle just about any terrain or obstacle without resorting to it outright cheating like that walking in midair example above.

Sometimes things are overlooked though, and when that happens you get to see hilarious results in pathfinding. Atheon and the Templar in the Vault of Glass raid in Destiny 1 are prime examples. When the raid was first launched, Atheon and the Templar were the bosses of the first raid, and the developers overlooked a tiny hole in their pathfinding logic that let players absolutely abuse the system for hilarious results by letting them be pushed or tricked off a ledge to their deaths. Bungie has never quite recovered from that mistake, and you’ll see the influence of that in every other boss in Destiny 1 and Destiny 2. They really don’t want something as basic as that to occur again.

But that’s just an obvious example of pathfinding. Sometimes it can be a bit more abstract, like in Castlevania: Portrait of Ruin’s mostly post-story zone, the Nest of Evil. Down at the very bottom of that gauntlet of nasty monsters is an encounter with a creature called the Doppelganger. and the gimmick of that fight is that it copies all the currently equipped equipment for Jonathan the vampire hunter or Charlotte the witch, depending on who it copies.

If it copies Johnathan and he’s had his sub-weapon unequipped and is using the Illusion Fist weapon, then all the boss can do is walk or jog towards you and never really fights at all. The reason for that is that the Illusion Fist doesn’t have an attack animation, so the boss can never fight with it. That is a really easy way of beating that particular boss.

That’s it for this week’s Video Game Tuesday!