In order to make a crowd more than just part of the scenery, certain elements have to come into play. As to whether Absolution’s Crowd Technology would be randomised or predetermined, Bobby had this to say. “We have both. The basic crowd locomotion behaviour is randomised and crowd members simply wander around the level looking at market stalls or fireworks. The predetermined behaviours kick in when events get triggered like explosions or gunshot or if a crowd member sees a dead body. At this point, these crowd members will react and change their behaviours to appropriately deal with the situation. This allows us to have complex gameplay within the crowd and not just have them wandering around like headless chickens.”
At some point during the game, the chances are good that Agent 47 will upset the crowd. Whether it’s due to aforementioned explosions, gunshots or a poorly disposed of cadaver, it seems that Agent 47 will be able to use the crowd as a double-edged tactical tool. “If he can get in front of the fleeing crowd, he can force them to change direction or just hit the ground in fear. Although, it’s not in 47’s favour to panic the crowd as then that makes it easier for the AI enemies to spot him and engage. But if the player wants to take a more action-oriented approach to a level, we want to reward them with a satisfying level of carnage and panic.”
We asked Bobby whether we can expect to find any Templar-types in the crowd that are willing to stand up to the tyranny of a lone assassin. Bobby’s response was understandably practical. “Would you try to stop a really big scary bald guy with a gun? I wouldn’t. I’d run like hell. So no, the crowd members won’t try to stop you; but they aren’t always as scared as I would be. I think that players should definitely experiment with the crowd once the game is released.”
But while you mightn’t come up against a vigilante who’s willing to go toe to toe with your Agent 47, you won’t necessarily be immediately punished for the smallest of mistakes in a crowded area. According to Bobby, the severity of your actions will determine the level of the crowd’s response. “[It] depends on the type of ‘mistake’ the players makes. Certain actions like leaving a dead body in a crowd is something that the crowd can react to and then recover from, but things like ‘accidentally’ opening fire in a crowd will cause mayhem and panic. It is definitely not a binary crowd where the smallest mistake will just cause instant panic.”
Hitman: Absolution and the engine that’s powering it, Glacier 2, are being developed side by side, which raises some interesting challenges for the team at IO Interactive. We felt that the aforementioned multiplatform memory restrictions would have been limitation number one, but it turns out there is something more foundational that stands as the biggest challenge to controlling complex artificial-intelligence systems in games.
“The hardest problem faced by AI programmers today is one of knowledge management. Even though the decision making tools have really matured over the last few years, knowledge systems haven’t kept up. As environments grow more complex, the range of actions available to an NPC grows with them and so does the amount of knowledge an NPC needs about that environment to be able to function within it. Especially for games like Hitman: Absolution, where the AI is required to constantly and smoothly transition between states and goals, knowledge representation and management is critical. This increase in required knowledge becomes really problematic to manage from both a useability and performance standpoint and I feel that this will be the next big topic in the game AI field in the next few years.” You heard it here first.
Consoling PC Gamers
Multiplatform development isn’t going away anytime soon – particularly not for popular franchises – but the unfortunate reality for high-end PC owners is that such games are coded with the lowest common denominator in mind. Given the aforementioned hardware restrictions of current-gen consoles, we were eager to ask Bobby how IO Interactive is handling Crowd Technology in a gaming world where console memory constraints limit the feature-set possibilities of such a multiplatform title.
“I think we’ve been quite smart with our design and so we’ve been able to get the crowds within the memory budget set for our levels. Even though memory was a problem for us, GPU performance was always more of a concern, especially on the consoles. On the flip side, there is a large benefit in developing for consoles in that it really forces you to be performance and memory conscious. Any performance/memory wins on one platform are usually wins for the other platform as well.”
“Of course, the limited memory does constrain us in a lot of ways but, for the most part, the constraints are more on the content side and not so much on the tech [side]. The bulk of the memory cost of the crowd is content-related (animations, models and textures), and the actual core crowd memory is trivial in comparison. Even with the restrictions, we’ve worked really hard to offer a large degree of variety for the crowd actors.”
For your (multiplatform) consideration
We pushed Bobby a little further to see if high-end PC users could expect anything more from Hitman: Absolution’s Crowd Technology given the access to additional/faster RAM when compared to current-gen consoles. “Of course, we will crank up the visuals (allow for more high-level-of-detail characters) in the crowd but there will be no changes to crowd size across the platforms. The crowd is a core gameplay mechanic and not just background decoration, so the crowd density has been carefully tweaked by the level designer to match each specific level’s topology and gameplay goals.”