|
News Original From 
7 Ways to Make Your AI Smarter
by Robert Hale on 06/24/09 05:18:00 am
Prompted by this article over at Bit-Tech on How AI in Games works it made me want to blog about some of the ways you can make your enemy AI appear smarter without having to re-write your AI back end or invest in expensive middleware.
 |
SCRIPTING
A huge amount of what convinces us a game has good AI is often completely scripted. Nothing ruins the illusion of AI like the Level Designers treating them purely like cardboard cutouts or filler. What the AI is doing before they start fighting is just as important as what happens during the fight.
My favorite reference for believable AI scripting are the No-One Lives Forever games. Yes you couldn't go more than ten yards without stumbling on a pair of AI guards having a conversation but it adds so much to their characters that you become far more forgiving towards them.
The arrival of an enemy is a great opportunity to make them seem smarter than they really are. AI that Rapel down a wall before fighting you or who shout for backup when they see you causing two more enemies to sprint around the corner. These are almost always scripted events but most Players will attribute it all to the AI.
Even just adding Patrol routes or some good ambient animations can make a very simple AI character appear more inteligent.
 |
FEEDBACK
AI that don't tell the Player what they are going to do before they do it look stupid.
In Half Life the Soldiers would always shout "GRENADE!" before they threw a Grenade at you. When they shouted "Flank Left!" an AI would always run out of cover moments later.
You are making your enemies appear as if they have goals and that they are trying to fulfill them. If the player doesn't know what the AI was trying to do then alot of their actions won't make any sense. If a Soldier just ran out of cover then the Player would assume the AI is stupid for leaving cover. By preceeding it with the command "Flank Left!" the enemies behavior is given a context that makes a stupid suicidal manouvre appear inteligent. Your enemies don't have to actually Flank anybody. They just need to say that they are before they move somewhere else. The Player will assume the AI is trying to do something very clever when they are really doing something immensely stupid. It's all about context.
Above all else AI that are talking to each other and the player appear more Human. The Grunts in Halo would have seemed very stupid if they had never said anything. Instead you always knew what was going through their tiny minds as a result of your actions.
 |
ACCURACY
If your enemies carry guns then don't turn them into Storm Troopers (unless they ARE Storm Troopers in which case it's OK). While the Player should have an advantage ov er the AI in terms of accuracy making the AI too inaccurate will just result in them looking stupid. If the player realises that they can just stand still in the open while they pick off the bad guys with a single headshot each then their sense of immersion will be completely broken.
Below is a video I made when we were making Wheelman to indicate just how "Stupid" AI can appear when they are inaccurate. The good stuff is at about 1:50.
Playing Half Life 2 Unsympathetically (YouTube)
If you want your AI to miss then put some effort into making them miss believably. If they are using automatic weapons then have them group their shots in a burst and have the entire burst miss. Don't just spread the shots out in a cone around the player because it's much more noticable.
If the Player is standing still in the open looking at the enemy then the AI should tear the Player a new one.
 |
 |
 |
 |
| 
7 Ways to Make Your AI Smarter 
