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The Craziness of the Aggro Radius
By Cameron Sorden | February 22, 2008
The idea of the aggro radius is inherently understood by longtime MMOG fans, even if you don’t describe it as such. It’s the knowledge you develop over time, by the harsh experience of repeatedly being attacked, that there’s a magic circle around your enemies which if entered will cause them to start angrily hurling everything they have at you. Eventually, you learn how big it is and how to avoid it. Look, I drew a picture.
This concept, however, is completely unintuitive for people who don’t play MMOGs. When my fiancee was first learning how to play WoW, I explained the concept to her. She hated it. Even though she knew there were these invisible circles around her enemies, she could never figure out how big they were or whether she was successfully avoiding them (she wasn’t– leveling with her was interesting in those days). It really annoyed her that she could be standing in plain sight of an enemy whose friends she had just killed, but the enemy wouldn’t even glance at her until she wandered into its circle. Meanwhile, enemies that she hadn’t even been able to see would run over a hill to attack her during a fight with something else.
The aggro radius is something you almost never hear discussed when someone is new to an MMOG and is being taught how to play. It’s not even something that developers put in tutorials. It’s just assumed that people will understand that getting too close means that stuff will attack you. Usually, someone has to explain the concept of the radius to people after they ask why other monsters keep interrupting their fights (after a few unpleasant and un-fun face-plants from adds). If you think about it though, it doesn’t really make sense.
Try to look at the concept with the fresh eyes of someone who’s never played an MMORPG. In real life, we rely almost entirely on vision and sound to detect and avoid threats. If someone throws a ball at you, you don’t sense it… you see it coming and catch it (or duck). Similarly, if someone comes up behind you, it can be quite startling when you turn around and see them. Most people won’t just sense them. Suddenly, you’re playing a game where many aspects of the physical world carry over. There’s gravity, 3d spacial navigation, acceleration and deceleration (in some cases). You can hide from other players and even monsters sometimes by staying behind walls. But if you back 15 feet away from a monster, it leaves you alone. It’s effectively blind to you and anything you do– even killing 20 or 30 of its friends.
The aggro radius is such a staple of modern MMOGs that most of the time, we don’t question it or even think about it. Every game on the market which has monsters of some sort uses the mechanic. Clearly, it works, especially given the density of monsters per square foot in MMOGs. If they could all attack you on sight, you’d be dead pretty quick. But is it necessarily the best way to handle things? What I find interesting is that this is one of the few longstanding MMOG traditions that wasn’t stolen from a MUD or PnP predecessor but rather evolved as a necessary effect of having graphical environments. It’s certainly not the only way to do things, though. Is there another system to get monsters engaging players that could be more fun or more intuitive? Or are we stuck with aggro radius as a mechanic for the foreseeable future?
I think it would be really cool to have a game world where monsters spotted and attacked players (or ran from them) the same way players spot and attack monsters. Think of the possibilities. You could have monsters with a far greater range of movement that actively hunted players from a distance. You could have rare monsters with cool treasure that fled at the mere sight of players, forcing players to stealthily hunt the exotic beasts for their loot.
You could breathe a lot of life into the NPCs and mobs of your game by making them act more like real creatures and less like walking piñatas.
Topics: Random |
February 22nd, 2008 at 4:55 pm
I’m all for it! I know AC2 had to dumb-down their AI quite a bit because the mobs were just vicious (and even trash-talked you! Ha!) but maybe, *just maybe*, we’re to a point where enough players would be accepting of smarter AI?
Get rid of the aggro rings, and let the monsters see as far as we can (although our graphics settings would certainly come into effect there… maybe a comfortable middle ground?) and line-of-sight for vision so if we can stay out of sight (and stay quiet) we can sneak by monsters from a very close range. DDO actually pulls this off pretty well, every character has a Sneak skill, not just rogues, and everyone can put points into a “move silently” skill if they choose to. It would be very cool to see some of what DDO did put to good use in an open-world setting.
February 22nd, 2008 at 7:40 pm
It wouldn’t be very noob friendly, and would make the game enjoyable only for people who have good attention to detail or responses. Unless they start off with only 1 or 2 mobs, and make the character that much more superhuman to compensate.
The ai for some FPS games lately are pretty nice though like Crysis if you’ve ever played it. If you’re in the woods, and there are soldiers in the forest they’ll yell out their position making everyone else alerted to your presence. Those soldier also start shooting at you from a mile away if you are carelessly walking on the beach instead of in the forest under cover.
If game makers start using that type of ai for MMORPGs then they’ll definitely create a wowkiller.
February 23rd, 2008 at 8:21 am
Processing on a mass scale. This sort of thing will come, I just don’t think coding practices are ready to optimize the number of cycles involved for AI like this on a massive scale. Devs are still sorting out working with a second core. I think the hardware is getting there, someone just needs to figure out how to use them best.
One thought I had was sort of a “player=center of the universe” type thing. Everything goes into simple mode unless a PC is within X range, then the advance AI kicks in.
Think of it sort of like the PC is a lantern shedding AI activation instead of light. Instead of mobs having an agro radius, PCs have an AI activation radius.
February 23rd, 2008 at 10:16 am
I’d love to see the circle of vision (aka aggro ring) changed to a cone of vision like FPS typically use, so sneaking becomes viable. I suppose you’d have to add “movement noise” to give the NPC’s some shot at hearing you sneak though.
I’d also love AI to make sense, ie. non-intelligent animals just beat on me, while intelligent humanoids, etc. get nastier and trickier rather than standing there playing Rock ‘em, Sock ‘em Robots with me.
Also, just because the mob has a red name and I walk into its aggro ring, does it *have* to attack? Maybe it’s normally a hostile creature, but every single hostile creature in the wild on Earth doesn’t blindly attack every time.
On that note, shouldn’t the AI ‘con’ us too? “Hmm… normally I’d kick the crap out of this idiot but he has friends… I’m outta here…” Or “yeah, my name is red but this solo guy is obviously way more powerful than me, why commit certain suicide?”
That would add a new element if the NPC’s ran in fear because we were so powerful. Would add even more of a surprise if they snuck off and got a bunch of friends.
February 23rd, 2008 at 11:02 am
As long as the mobs have a chance to attack and subsequently kill you, it would end up being extremely frustrating. People usually play MMORPGs to become heroes rather than run from lvl 5 Richard the Rat.
February 23rd, 2008 at 11:32 am
But it’s an MMO. When all the “heroes” are surrounded only by other “heroes” we end up right back to feeling pretty average, indeed.
By and large, people do play MMO’s because for the most part, you’re guaranteed to have a high chance to “win” each encounter. People like to win. It’s why AC2’s AI had to be dumbed-down to the point of mental midgets so the players could “win” more often.
February 23rd, 2008 at 1:03 pm
[...] not really coming up with anything original, so I’m going to piggyback off Cameron’s post once more; this time on his post regarding aggro radius. While I do agree that the idea of an aggro [...]
February 24th, 2008 at 6:48 pm
I think we make jokes about this every time we run an instance as a group, the group of mobs that wander by and ignore us there, in plain sight, making chutney out of their comrades.
Realistically, no dungeon would have 100 guards wandering at regular intervals. You would have a group of guards up front capable of offering resistance and sounding the alarm and then a reserve big enough to swamp any likely party that showed up, with maybe a few checkpoints along the way.
But that would be no fun.
I will say, in Blizzard’s defense, that at least WoW has variable sized aggro radii. The lower your level relative to a mob, the bigger the range they can detect you, so at least the “safety zone” isn’t static the way it is in other games.
February 25th, 2008 at 11:39 am
“I will say, in Blizzard’s defense, that at least WoW has variable sized aggro radii. The lower your level relative to a mob, the bigger the range they can detect you, so at least the “safety zone” isn’t static the way it is in other games.”
Don’t forget Wow’s 20 yard range aggro when fighting tanked mobs. Casters/healers outside of 20 yards have reduced threat until they walk within 20 yards of it. It lets ranged dps/healers have more leeway when it comes to aggro management.
February 25th, 2008 at 12:42 pm
I would be happy just to see one dungeon with a proper LOS aggro.
February 25th, 2008 at 4:07 pm
[...] Cameron has some things to say about Aggro Radii over on his blog. The idea of the aggro radius is inherently understood by longtime MMOG fans, even if you don’t describe it as such. It’s the knowledge you develop over time, by the harsh experience of repeatedly being attacked, that there’s a magic circle around your enemies which if entered will cause them to start angrily hurling everything they have at you. Eventually, you learn how big it is and how to avoid it… [...]
February 29th, 2008 at 2:41 pm
[...] was in response to an article written by Cameron Sorden on aggro radius. Cameron mentions that it would be cool to have mobs ’spot’ Players and [...]
March 2nd, 2008 at 11:44 pm
[...] late to the party, but there’s been a conversation on MMO mob AI that’s been going on for a while now. The debate is how to get more “realistic” [...]