Blending Autonomy and Control: Creating NPCs for Tom Clancy's The Division

[Music] [Applause] good morning and welcome to blending autonomy and control creating NPCs for Tom Clancy's the division my name is true Rutner and I'm a game designer at massive entertainment which is a Ubisoft studio and I designed and implemented the behaviors for mostly combat NPCs in the division I'm here with Phil Dunstan senior AI programmer and will be sharing this talk in the first half I'm going to be discussing some of the high-level behavioral intentions for our NPCs and kind of the design philosophy behind them and then the second half Philips going to talk about more the low-level behavioral systems and the scripted control that we gave to level design

so we're going to start with just a brief overview of the division and then we're going to also give a brief overview of the combat NPC's in the division then we're going to move on to the design philosophy kind of what drove our decisions behind making the NPC's and then we'll briefly explore the different archetypes and factions then we're going to move on to what I think is a pretty important topic which is challenge scaling before finally concluding the first half with the structure of the behavior tree for those of you who aren't already aware Tom Clancy's the division is an online and multiplayer open-world shooter RPG we just released on March 8th since we're specifically going to be looking at NPCs though here's a brief video of the different factions in our game

there should be some audio yeah it's plugged in good to go all right sorry about that we'll continue it's a bit loud good turn yep if you guys are good to go okay great so here's the video of the affections take to our city started to collapse the dark side of humanity to control the streets

this city fell apart it's crazy out here every man for himself survival of the fittest you gotta take what you need in this world this world is our playground now that no one's here to stop us we got out of Riker's jail and we ain't ever going back in that cage it's all ours now we're the new kings of these streets [Music] these streets must be cleansed save our city we must burn away this disease each trace of it freedom is not a right Liberty is not a

given this city needs an iron fist to restore order there shall be no resistance it is the only solution this is not our solution our mission is to save what remains to save what's left of our city [Music] we are the division so the division features 36 36 I'm sorry different unique combat AI that we split into 11 different archetypes we put

those NPCs into five different enemy factions and we do have one friendly combat faction will briefly mention it but we won't really talk about it much today our ABCs feature a suite of different features such as a detection system a threat system scripted controls that level design can use to control our NPCs reaction to the player's vast array of abilities dynamic objective handling reactions to civilians and wildlife and various idle activities the majority of which Phillip will talk about in more detail in the second half our NPCs were both used in what we call the open world which is a less scripted and more systemic gameplay space and a more highly scripted story missions which are a bit more like kind of your typical third-person shooter missions as I kind of alluded to earlier we used a behavior tree architecture in our snowdrop engine which is a brand new proprietary engine

developed by massive one other thing before moving on I think it's just important to note that our AI was completly server side next we'll look at the four design pillars that we had for creating our combat NPCs the first pillar is that our NPCs had to support the idea that our game was both an RPG and a shooter so this meant that we needed to allow the player to play in different ways and use different roles so think like disruptor tank sniper medic and others this was especially important because we were a co-op game and we wanted players to combine their skills to synergize with one another and that also meant that they needed a reason to do so on top of that we incorporated tip RPG systems like agro and crowd control

that aren't always seen in shooters another thing we wanted to do is we wanted to incentivize the pre combat setup something that we coined as the investigation phase internally which basically gave the player the opportunity to scope out and plan for a tactical attack and finally of course because we were an RPG and a shooter we wanted to reward the twitch gameplay of a shooter so that was the basic timing and positioning and dexterity challenges that provides the next pillar was that it was important that our NPCs fit into a realistic setting the Tom Clancy IP is of course known for its realism and its highly detailed universe so our NPCs needed to have some kind of realism to them so they were constrained by that to some extent so it meant we couldn't rely on magic and sci-fi even though we were an RPG no at first this

kind of seemed like a bit of a limitation and it was a challenge but later we found that the constraints and the guidelines that provided actually empowered us way more than if we had kind of a blank slate to work with the player could go basically anywhere in the world in our game since we were open-world so we had a near one-to-one recreation of midtown Manhattan so that also meant that we needed to develop ways of encouraging the player to come back to locations when they've powered or leveled up although we mostly solved that through enemy level scaling most importantly though even though we were in this realistic setting fun was still the most important thing for NPCs our NPCs were mainly there to drive fun for the player so even though that some of their behaviors were a bit gamey we

decided that that was best for the game overall we felt like we could push the boundary a little bit on that and like personally I mean that's a bit hard right working in AI because sometimes we get our egos a little bit involved especially me and you you have to remember like why you're making the game in the first place our third design pillar was to create strong archetypes so this meant creating NPCs that fulfilled various roles that challenge the player in different ways this meant encouraging the player to use different tactics based on the enemy compositions now we created excuse me we created NPCs that that use different strategies and skills and that's synergize with one another and that was kind of a core part of creating combat was to create something we called combat puzzles for the player and that was where we use two NPCs that worked really well together now this of course meant

that we had to create really clear signs and feedback to the player and we did that through the UI color the icons in the UI the appearance of the enemies and of course they're out of combat in in combat behaviors the final and most important pillar though is one of continual challenge so our NPCs needed to provide new concepts and gameplay to the player over time because combat was such an important part of the division so we kind of introduced a basic roll out of our NPCs and the different skills but that also meant kind of introducing the loop of introducing something new having the player practice it then master it and then introduce new and more evolved concepts additionally we did provide multiple difficulty levels for missions don't necessarily need to talk about that

though for the case of this talk though so creating a continual challenge did pose some problems to us though in development because it meant that we needed to create a ton of different NPCs so I'll discuss how we attempted to solve this problem a bit later in the talk now that we've covered the overall design philosophy let's take a quick look at the different archetypes features in the division before we do that though I think it's important to note the real reason why you created archetypes the real reason we thought it was important is because each archetype poses a different challenge and we broke this down into six separate archetype challenges the first of which is what we call target prioritization and it forces a player to deal with an immediate threat or face the consequences the next challenge that we identified was a repositioning challenge it forced the player usually out of cover to a new

position to avoid a dangerous threat next was the minimize exposure challenge and this meant that the player had to minimize the time that they were popped out aiming or in between covers the target or during challenge challenges the player to figure out an optimal path for defeating the enemies next was the positioning challenge which encourages a player to move to an advantageous position now this is really different than the repositioning challenge in that it's a very proactive action instead of a reactive one and finally the endurance challenge was one where the player had to spend a lot of time in order to defeat an enemy now this is a table that we gave to our level design team to create interesting challenges so this table is really meant to kind of show which archetypes fit really well together when their skills synergized using the challenges that we showed in

the last screen before I move on though just a quick warning that the videos shown in this presentation from this point on feature test maps with incomplete lighting and propping so you guys probably are all aware of this just something to point out so down to the archetypes the first archetype that we had is what we called assault and that's kind of your basic cover using grunt it's your basic third-person shooter challenge but they're really there to kind of balance out the fireteam and and yeah they they were a grunt role within the fireteam is what we call them next is the retro archetype which runs directly at the player and forces them to prioritize them or face a consequences they got more dangerous as the player got closer so it was really important for the player to take him out as quickly as possible sniper archetype

pretty typical sniper long range high damage single shot very accurate they forced the player to minimize their exposure so not stay up too long not going between covers too often the thriller archetype throws a grenade or other dangerous objects to force the player usually out of cover so this is a repositioning challenge next are the controller and turret archetypes the controller sets up and fights through a proxy generally turret and repairs it if it ever gets damaged now the turret automatically fires at the player usually with the high rate of fire suppressing them but what this did was this introduced an interesting target ordering challenge because the player could make a decision if they wanted to try to take out the controller before the turret was set up where they could damage the turret and lure the controller out or they could damage or and kill I'm sorry the controller well the turret was up and have the turret malfunction on its own next is a heavy

weapons archetype suppresses the player with a high rate of fire force the player to minimize their exposure but what's different with this and the sniper though is they typically had kind of a long reload time and allowed the player to come up and kind of exploit them the next archetype is the tank archetype which are heavy NPCs who take a lot of damage to kill but they also generally deal a lot of damage as well they have weak points on them and this allows the player to position themselves in a way that they can hit the weak points and some require flanking and they always end up either damaging the NPC by a lot or crowd controlling them leader archetypes affect the behaviors of other NPCs generally making them more aggressive so it's advantageous for the player to usually take them out as quickly as possible next is the support archetype assist teammates by healing them generally think of like a medic or something like

that again it's a target ordering challenge but medics are also really defensive so the player also has to kind of position themselves if they want to take them out or lure them into a wounded ally and finally we have what we called special and that is basically all NPCs that didn't fit into any of their categories now this meant that NPCs in this category were a bit hard to define and thus the player didn't have a lot of kind of education necessarily on the specific mechanics so we primarily save these for endgame to kind of keep it interesting for the player now we're going to take a look at our five enemy factions as well as our friendly combat faction now these are introduced in the order of which they're introduced to the player so the first faction the player

will encounter are the rioters they present a really introductory challenge to the player there are starter NPCs so they're really there to kind of teach the player the mechanics of the game and really introduce them to the various archetypes that we have in the games so the snipers throwers with very little distraction they're disorganized they're unskilled they're low-tech the next faction the player will encounter are the cleaners now the cleaners present a slightly more advanced challenge to the player and most notably they introduce a few new archetypes of the player for the first time and that's the controller and les turret archetypes and then of course the tank archetype they're a bit more organized and they're a bit more deadly than the rioters the third faction the player will encounter are the Rikers and the Rikers present a slightly more advanced challenge than even the cleaners and they're a bit more coordinated so this is the first time

you cook the player will kind of see coordination and combat the fourth faction is the last man battalion and the last man battalion is a militaristic faction so it fits kind of the clan CIP really well and it provides advanced challenges to the player they're organized they're tactical and we'll talk about some of the things that they do in just a bit and the last enemy faction that the player will encounter is the tier 2 of the last man battalion now narrative Lee they're the same as the last minute battalion but they actually are gameplay wise a pretty separate faction they're intended primarily for endgame because they present such an advanced challenge to the player we also blend our archetypes a little bit at this point so we kind of blend what a controller is with a support for example so we kind of changed things up a little bit for the player they're very organized they use a lot of group tactics so they're really intended to be

a difficult play and last but not least is our soul friendly faction combat faction they should say which is the joint task force or the JTF they're pretty basic combat behavior is only a single archetype and really their main purpose was to be a cheerleader in the game for the player so they would just tear the player on in and out of combat so now that we've talked about the different archetypes and factions in the game I want to talk about the NPC challenge tiers which was pretty important to our game it'll combine kind of these two components so to provide a continuing continually involving challenge for the players we took each of the five factions and we split them up into tiers starting with the rioters and ending with the last man battalion though we had a bunch of different aspects that I

listed there that we improved as we increase the faction tier so we did this really for two reasons like one we wanted to provide a continuing evolving challenge for the player which is one of the pillars I mentioned if you're a number but possibly the more important reason to that as well or equally as important is that we needed a quick and relatively easy way to create a lot of NPCs so we kind of picked components that we thought we could tweak that would be interesting in order to provide the greatest variety possible so we're going to briefly look at each of these elements and how they're scaled and we're going to start with reaction to player skills and actions so to efficiently scale the way that NPCs reacted to the player's vast array of abilities we created what we called profiles or reaction profiles now these profiles changed depending on the

faction and the role of the NPC which I'll talk about in just a second so first is the dump profile and this is used exclusively by the writers and it allows the player to be a lot less careful with their abilities and how they use them so the player doesn't have to use a lot of consideration they get a lot of you know kind of bang for their buck with their skills so as an example if the player uses a seeker mind on NPC and the seeker mine is an autonomous ball shaped bomb that rolls towards an enemy that explodes in close proximity a dumb profile NPC will run away in a panicked way and they're gonna run towards an ally a very reluctant ally actually and hopefully the bomb will explode and kill them or damage them both next is a default profile which is used by the majority of our NPC's in the game it's slightly better than the dumb

profile in terms of the reactivity in the way that the NPC avoids the players abilities but it's still not very effective so in the example of the seeker mine instead of running towards an ally the NPC just runs away from the seeker mine in a panicked way the next profile is the elite profile and the elite profile is only used by the tier two of the last man battalion and elite role NPCs now this profile actually allows the NPCs to counter some of the player skills so if we looked at the secret mine example again an NPC targeted by that will roll out of the explosion next is the tech profile and the tech profile is only used by it's kind of rare so it's only used by a few NPC's in the game but it allows NPCs to counter or even hack some of the players skills again to use the secret mine as an

example if the player deploys it towards them they will hack it send it right back to the player and the players won't seek your mind will blow up in their face and the final two profiles are the heavy and the turret profiles which are used by the tank and turret profiles respectively so heavy profile the NPC doesn't usually react to a lot of things because they're kind of big and heavy but they do have a couple few unique in ways that they counter skills as well and finally to use the secret mind example the NPC will actually kick the seeker mind if it gets close to them and then have it destroyed so our next difficulty modifier that we used was movement speed and style so we increase the movement speed basically of NPCs as we improve the faction tier however we

only limit this to the strafe speed of the NPC's and the rush speed of rushers now we primarily did this for a kind of technical and production related reasons but we actually thought it would ended up being pretty sufficient so some NPCs actually also had some kind of panicked movement styles specifically in the lower tiers and then as we got up into the higher tiers they used more composed movement styles additionally we had two different overall cover movement styles so when NPCs were moving to cover the first one was what we called mixed movement where an NPC would sprint to a location stop shoot and then either run into cover or strafe and shoot and took very short distance the other option was called full strafe where the NPC would strafe into a cover while shooting the entire way now a faction could have one of these two profiles so we made it pretty easy

the next modifier we had was the group behavior modifier which we have split into two groups which again the faction got one of the first was what we call disorganized which is where NPCs didn't coordinate their movement they didn't communicate to each other so they didn't provide cover fire and then we had organized and organizes where the NPC's did provide cover fire fire for each other they did coordinate their movement and they also actively attempted to swarm and surround the player the next modifier was cover usage so we split this into two major groups one of which was assigned each faction the first was inconsistent where MPC's would occasionally wander out of cover and start shooting really aggressively at the player by contrast the consistent one meant that NPCs always stayed in cover and if they ever found themselves

out of cover for some reason they would attempt to get back in immediately though one of the more important ones was skill usage so we scaled skill usage not only in terms of the frequency in which NPCs use skills and you know like the speed and the duration and things like that but we also ended up swapping out entire skills so as an example let's look at the thrower archetype so the thrower archetype starts off in the lowest faction the rioters with tear gas grenade which is non-lethal provides a satisfactory the player it's not particularly dangerous but if there are other NPCs around it can be a little bit dangerous than the player so they still want to avoid it next as we move up into the cleaners faction we swap that out with an incendiary bomb it's basically the same thing as a tear gas grenade except it does have damage

over time included after that we improve with the Rikers in the Rikers we swap out the incendiary bomb with a frag grenade and the frag grenade deals quite a lot of damage and it has a shorter fuse and finally the last kind of evolution of the thrower is the last man battalion where we actually swap out the frag grenade with a grenade launcher that shoots three consecutive grenades that explode an impact so hopefully you can kind of see a progression of challenge there for the player and finally it I think it's worth mentioning that we did a little bit of Health kind of stagger or suppression resistance and damage and accuracy improvements with faction tear we tried to keep this as minimal as possible because we found that all the other things that we do like behavior I'm sorry the players respond to a lot better so is bless about numbers and more about behavioral changes so I'm going to show

a video about or that compares the first faction or game the writers with the final the most advanced faction the tier 2 the last man battalion now please note the differences in the cover usage the skill usage the tactics and their skills in combat and also just a quick note just a reminder that this is a test map and I have God mode in god mode on so I don't embarrass myself by dying

[Music] thank you too

[Music] so we also scale difficulty and a few other ways which I'll just briefly mention here so we scaled the challenge of individual NPCs by using something we call NPC roles which is basically our one way to change the difficulty of an NPC without changing the faction so we start off with the what we call veteran NPCs which is the first improved role and they're essentially the same thing as normal NPCs except they have a little bit better weapons and they feature the addition of armor so their health bar looks very visually different to the player the next role is elite and elite NPCs have improved weapons even more improved actually than the veterans but

they also have special ammo types we give them brand new skills and they have improved ability reactions so they start using the elite profile for example they also have additional armor and even better aiming one quick note though and the skill and modifications we actually ended up just using the next faction up or two factions up skills generally and that was mostly just to save production cost and end up working actually pretty well I think and then finally we have the named role NPCs which are basically just reserved for bosses and there are the elite NPCs but they just have more armor unique weapons and do a little bit more damage so my final topic before passing the stage over to Phillip is just to talk really briefly about the structure of her behavior tree so as I talked about before one of the big

challenges we had on the project was creating a huge number of NPCs and of course the way we decided to do that was to make our behaviors is modular and reusable as possible so we split them up into the groups which you can see here so I'll kind of take you through the flow of the NPC behavior so we first start off with what we called high priority of critical events and so that's basically an evaluation of is there a grenade nearby is there a seeker mine that's attacking me or things like is there a status effect applied to me or is my weak point exploding something like that now if those checks fail we move on to what we call scripted events and these are all events that are level designed controlled so these are move orders and things like that so Phillip will be talking more about that in just a moment we then move on to low priority critical events and NPC objectives the NPC objectives being dynamic objectives at

the NPC's do it affects their behavior and movement then if that fails we move on to our detection system which is basically controlling whether the NPCs in combat after an idle investigation and so forth then we move on to some of the very specific archetype behaviors before finally ending up with the base behavior that almost all NPCs share now that limp that's that controls cover usage reloading shooting group behaviors things like that you'll notice I also pointed out the faction tier modifier so all those things that we listed before those all are listed in those blocks and are controllable in those blocks so before digging any deeper though in the behavior tree I'm gonna pass the stage over to Phillip

yeah thanks joy and good morning to everybody my name is Phillip Dunston and I'm a senior AI programmer on Tom Clancy's the division you've just heard drew talked about our design intent and philosophy for the embassies and how we differentiate these through their actors archetypes and the factions I'm now going to describe some of the more technical elements of the NPC behaviour and I'm going to begin with a brief description of the combat encounters before diving into some of the behavior systems that underlie our embassy behaviors I will then talk about how we give control over the embassies to level designers both directly and through these behaviors and finally I will finish with a few lessons that we learned working with cross discipline teams and particularly working with level designers the division is a mixture of open worlds and narrative driven story missions open world

consists of emergent behaviors with roaming mobs interacting with level designs place encounters and our story missions are generally authored linear series of encounters with a very predictable player movement across both open world and story missions a core creative intent on Tom Clancy's the division was to give the player control over how calm bears initiated and as drew mentioned earlier this is called the player investigation phase the player pole skill helps players identify from high-priority targets gameplay gameplay mechanics allow players to coordinate targets and to synchronize their combat and importantly we wanted to allow the player to be able to relocate prior to the beginning of combat for a group of players to be able to move to flanker mob of NPCs or for a single player to approach within an optimal combat range based on their combat loadout to make this possible we needed a system to allow players to

approach the embassies without triggering immediate combat and that was the responsibility of our detection system our detection loop is built of five alert levels escalating an NPC from idle up to investigation when a target is spotted into combat after combat if all hostiles are dead NPCs can transition to a combat investigation phase and from there either back into idle or to combat as drew mentioned spoke about earlier the alert level controls some of the behaviors in the base of our embassy behavior tree the detection system is built as built on top of the alertness value and this is affected by both audio and visual stimuli and is defined per archetype our audio visual stimuli are governed by standard vision cones and I'm sure you familiar with these we have forward and periphery cones and these

are shown in yellow in a diagram in the video video playing we are in addition to the standard vision cones we have instant combat cones these are shown in orange if a target is seen within the instant combats cone combat is triggered immediately to prevent the player from sneaking out behind an NPC we have a 360-degree close awareness area and our vision cones differ if an emphases in combat or out of combat if the NPC is aiming or not aiming and they are also modified by the weather weather interestingly to allow the the player to be able to sneak up on a group of NPCs out of combat we modify the line-of-sight test slightly so that a player in low cover is remains hidden more easily our audio events contain a sound type and a radius the radius governs the maximum distance at which the sound can be heard and the sound type specifies limits the maximum alert

level that can be triggered by that audio event and interesting in suspicious sound sorry can trigger well such as player vaulting of a cover can trigger the NPC into a investigation let the robonaut into combat and at a threatening sound such as shots fired or explosion can trigger combat in addition to creating pre combat gameplay opera up options for the player we also want to give the player the ability to exploit the detection system during combat and to facilitate this the NPC's remember the last position a hostile target was seen the last name position contains two points the aim at position and the navmesh position the aim at position in green provides a point for the embassies to aim at so where they no longer have line of sight to the target this is particularly useful where the target is in low cover we can position the aim at points

slightly above blue cover or outside of corner cover so that bullets and flames are seen to naturally flow past the cover edge with the occasional shot hitting the cover the navmesh position allows NPCs to find positions that can see behind the cover either for flanking or as part of an investigation behavior moving on to our position system this is core to all of our combat behaviors and we use this for both cover and non cover position queries we don't use any local steering on the division so we use this for nearly all of our NBC government combat movement and some of our out of combat movement the position system operates on pre generated tactical positions across six square kilometers of Manhattan we have almost two and a half million tactical tactical positions both cover and non cover our cover base positions conclude information about the

cover depth the cover height and the cover facing direction and I'm non cover positions are generated on a rotated grid with approximately 4 meter spacing we use a rotated grid here to avoid some of the artifacts arising from the north-south and east-west orientation of most of the buildings and streets in Manhattan as behavior to run on the server these tactical positions are permanently resident memory to perform queries on the tactical positions we use a single UBA position evaluator with memory parameters affecting the scoring some of those parameters are shown here to make it easier for behavior authors we expose sets of parameters through different behavior tree nodes you can see in the screenshot here we have a fine cover position and find uncover position nodes and these are the workhorse nodes of our combat behaviors in addition you can see other types of movement queries in the top right for example you can see a node which allows an NP speed to find a suitable place to

place a turret and the bottom right we have a node for an embassy to find a position to run away from a nearby grenade we often perform multiple successive queries in behaviors with more and more permissive parameters for example we might perform a cover position query with an optimal range if that doesn't work we'll fall back on an on cover position query with a lot with requiring line-of-sight to the tiger and finally if both of those fail a cover or a non current position query without line-of-sight and we found that this gives us better results than trying to identify a single to best position in a single pass it avoids the challenging problem of having to track trying to tune the different weights for the different parameters for the different queries caching both navigation and line-of-sight results was key to making this work with acceptable performance in addition to combat positioning we reuse

the technical positions and the positioning system for investigation behaviors and other non-combat behaviors the example here is our scripted investigation behavior a group of NPCs is instructed to search an area and I want to pretty write something that drew dimensions here this is a lot of the videos and screenshots you're seeing are from are not executive of the final quality of the game they're taken from test levels generated in our snowdrop engine during development so back to the example the search query here is a simple algorithm we take all of the tactical positions within the search volume when we query the positions we look for a position based on the distance from the NPC and looking for corner positive coverage positions and finally as the npcs move through area we eliminate positions that have become visible to the player this is a simple algorithm and it works well with multiple aged muscle agents the division

finally I will talk about the threat system the division is designed to be played co-op with up to four players and so we needed an agro staff threat system target threat scores are calculated from a base threat which is made of stable parameters such as whether the agent is a player or whether they're currently behind cover and did action threat which is usually a single frame event such as another target shooting or the target using a skill and the action threat decays over time so those are our core some of our core NPC behavior systems we're now going to take a look at how we allow emphases levels I'm sorry to control MPC's both directly and through these systems the snowdrop engine provides level designers with a visual scripting environment if you've used CryEngine or unreal before you're probably familiar with this tolerance environment we provide nodes that allow

level designers to issue low-level what is - NPCs to sentient NPCs alert level and to modify positioning and threat systems and we also provide a nodes to set high level objectives on groups of NPCs one of the first tools that we made available to level designers was lower level orders and we call these NPC orders NBC orders are typically used to control a single embassy in a scripted environment such as putting a hostage behind cover or having an NPC follower player it's tempting to implement these as an override behavior that replaces all of an MPC's behavior but we found that much more effective to implement them in the behavior tree as a reaction to a critical event in this way we can have them override the base NPC behaviour but still have the NPC responds to very high priority critical events such as grenades or has player skills now I'd like to take a moment here to talk about level design

in my experience level the Sun is like to have full control over the player experience and part of that is having knowledge about how the Embassy is going to react in any given situation so what happens when you give level designers who like to have full knowledge of the embassies you give them fine positioning control over NPCs with embassy move orders well to grow a bit of an old name here you get move orders for everybody you get a move order you get a moove order you get a move order and you don't get a move water and so this thanks Dave yeah okay so this isn't this isn't very good because Nouveau move orders have some serious downsides remove all orders skip the evaluation of the underlying systems we no longer use the results of our sensory and detection system and our threat evaluation system and so move all

over the level orders break NPC reactivity and this is really big for players players seem much more likely to notice missing NPC reactions to events in the environment than they are to notice missing NPC abilities also NPC orders don't provide any context to the previous that follow those move orders and take for example we have a move order that was interrupted by a combat the behavior that follows that interruption has no information about what the what the MC was trying to achieve with that move order and finally I think and I think most importantly low-level orders force level designers to have to create AI they need to plan for all of the permutations of combat in the environment and they need to script accordingly and this isn't a burden that a level designer what level designers want and it's not one that we should be forcing upon them so we're going to prefer systemic approaches that work with the behavior systems rather than circumventing them so the first thing we

next thing we gave for level violence was the ability to modify the positioning system and initially this were through NPC zones an NPC Sonax is like a binary filter to the positioning system the positioning of position evaluator will only accept positions that within the volume specify the empathy zone if NPCs are outside of the zone then we can allow positions that move them closer to the zone but once inside they will remain within that zone however this doesn't work so well in the open world short-range combat embassies break down at the boundary edges when their target is outside of the zone and even medium-range NPCs can be sniped from with the punitive from players from outside of the zone so we also add a tactical position modifiers and attain the positional modifier was a soft version of NPCs zone we changed the position evaluator to score points that are close score positions that are closer to the volume higher and give maximum score bonus to positions with that are within the technical position

modifier volume even still we found that these modifiers could be become easily overused one other problems level designers were trying to solve was trying to solve was that with position modifiers was to prevent combat in one area from attracting all of the NPC's on nearby and this was coming particularly often within narrative driven story missions but it could also happen in the open world in the denser parts of Manhattan a level designer would set up different accounts as in adjoining rooms but as soon as combat initiated then all of the embassies and that mission would come running so we gave Louis sinus two additional pre combat alert levels the first of these is the scripted investigational at law and we saw this early when we looked at the scripted behavior um when it can how it really is the the tactical position system with the scripted investigation NPCs were continually to search an area ad infinitum and second we gave them a

scripted combat alert level and a scripted combat level instructed embassies to take cover and act as if combat was going to take place with his level Direction specified by the level designers importantly the both these level alert levels skipped the initial combat reactions or initial reactions from an NPC entering combat such as barks and and there are the combat reactions and they don't transition back into either combat investigation or idle the NPC's will stay in those areas until combat is being has begun finally and some what's very successfully we added high-level objectives and you can see the list of halibut directives that we provided here these objectives are built on top of the underlying NPC systems they modify the position of the detection system the position of variant and positioning system and the threat system the primary behavior for these

objectives was implemented a slightly lower priority than the embassy orders but throughout the behavior tree the NPC objectives can be used to provide additional context to behaviors animations and barks and high-level check this can be used in both in combat and out of combat situations and we had taken a deeper look at one of these objectives the interact with prop objective so for the interact with prop objective a group of embassies is instructed to move into the vicinity of an object and if there are no high um high value threats then to start interacting with that object we modified the positioning system to score the positions near the object higher and score even higher positions that are between the object and any tie and any hostile targets and so embassies are naturally seen to take cover in front of players approaching the the object we modify the threat system to increase the

value of the threats that are in the area around the object and further increase the value of threats that are targeting NPCs that are interacting with the object and finally we introduce new behaviors to move NB C's that are a long way away from the objects near the object and also if there are no high value of threats and the vicinity for an NPC to begin interacting with the object so the question arises then or low-level orders or high-level systemic behaviour what I tell the truth we needed both in the open world we prefer this the scenario behaviour of the high level objectives this Mendel's the unpredictable player movement and it allows us to maintain as much NPC reactivity as we can low level mission tava are great and story missions they give fine control over NPC positioning and they work much better for scripted sequence than animation sequences they are more interrupts and they don't have the same constraints with initial player main PC positioning

we've found across low-level orders and high electives that players will find a way to break all the variant pc behaviour but we and certainly low-level orders are more brittle than the hell objectives but we certainly still found them very important to have for the division so I've now discussed the technical aspects of the MC behaviour how we give the controller level designers and I'd like to finish up with some of the lessons that we learned working with cross discipline teams and particularly working with level designers and I think this relationship is one that doesn't really get discussed enough we often talk about the relationship between our designers and I our programmers or animators and AI programmers but rarely the relationship with level designers and yet level design is so important to good AI good level design matches the capabilities of the AI it shows off that the strengths of our AI and it hides any shortcomings and of course the most important thing

about any relationship is communication and we're talking about two-way communication here yes we need to educate the level designers on the features that we're giving them to them to control the embassies and how we would like them to be used but we also need to talk with them about the bugs that are having and to try and identify features where we can improve the tools that we're giving them and the AI behaviors in the bull scuse me and the AI behaviors in the level sign they're creating I'm going to grossly generalize here but I'm a bit here and I certainly don't mean to make any any offense at all to level design in my experience level designers I used to making things work with the tools that have available to them and the systems they use are often in flux during the whole arm state of the project development they often have very tight production schedules and maybe to be too busy producing content to be able to make suggestions on a IBM features so talking

to them about the issues they're having and how we can improve our tools it becomes even more important we found that wiki's and emails are completely insufficient for this during the height of development wiki pages get bookmarked emails get marked as follow-up but no one gets a chance to read them on the division we use cross discipline teams to great effect on certain particular games gameplay aspects one of my favorite things we did on the division was weekly sync meetings with key level designers and members the NPC teams and this was a particularly effective with our remote Kotov teams these level designers because we came funnels for the type of communication that I'm talking about between level designers on their teams NEMC team and also and I very proud of this as we had a system an embedded level of signer within the MPC team this level designer became an informal point of contact for other little signers on the project with problems they were having and the level designer could respond quickly and investigate em and the detect patterns

in those problems validation and debugging tools are also very important we can validate as much as possible in the editor for instance we can check the volumes that are passed to investigation areas or NPC zones to make sure they contain enough tactical positions to be viable one of the powers of the snowdrop engine is our ability to create and iterate quickly on test levels and we use these both for reproducing the problems that level designer having away from the complexity of the full game we also use it to provide examples of the intended use of our AI to level design both of these tasks became very important role of the embedded level designer on that team but finally we is we found it very useful to expose our debug drawer environment to level designers not all of the level designers would use the debug drawer but some of them found it very helpful to be able to quickly debug simple AI problems on the division we

have a very probably havea tree editor in debugger and you can hear about more of this tomorrow with Janice Gilbert's talk in the AR summit but we have found that this was never used at all by level design this is simply to lower level than that they are interested in for debugging NPC behaviors inside conclusion you've heard me sorry you've heard Rui talk about the four pillars of design that we use for cranium pcs how the division is both an RPG and the shooter how we prioritize fun but we respect the realism for the Tom Clancy universe how we create strong we create combat Chatham Challenge puzzles with strong archetypes and how we continually challenged the player through invested increasing Embassy behavior complexity and abilities you've heard me talk about the behavior systems and how we give control over level sign to be over the embassies both directly and through these systems and finally you've heard

me talk about the cross discipline teams and particularly that relationship with all design that I think is so important like the shadow big thanks out here to the four Ubisoft Studios that worked on the division lead studio massive entertainment and our three code of partners reflections Red Storm and Ubisoft annecy there are a lot of people that went to making contributing to the NPCs on the division and we thank heaven for a quick plug for Jonas Kubrick's talk tomorrow in the AR Summit Jonas will be discussing behavior tree editing in debugging tools and also add funiculi step enough talking later in the week at the main conference on the global of illumination in Tom Clancy's the division I'm pretty sure there aren't any time for questions today but if you do have any questions drew and I will be around here afterwards we will also along with Jonas via the Ubisoft lounge on Wednesday morning from 11:00 to 12:30 and you're all welcome to come and ask us questions about the division without

working on AI and about working at Ubisoft and in particular if you'd like to speak to us about working in Sweden a massive entertainment we'd love to hear from you we're always looking for good people thank you very much you