Driving Emotionally Expressive NPC Animations and Behaviors with a Designer-Friendly Pipeline

[Music] thank you I'm Gucci boyda working at Square Enix advanced technology division as an AI engineer and today I will talk about driving emotionally expressive NPC animations and behaviors with the design of any pipeline so first I would like to thanks all the approvals that worked with me on this project so thanks a big thanks to them so as of today relationships between users and characters has been mostly unchanging it is often one directional uh from player to character and that Square Enix have been technology division we believe that the realization of deeper communication between users and characters will bring a completely new gameplay experience I'm a research efforts on character interaction already bought some fruits with our experimental emotional

pipelines that I introduced at DDC 2019. this pipelines allowed our NPCs to be more aware expressive and Lively uh since that time we started a new project named wonder where the philosophy was gods do not play dice the meaning was that AI based game design should not rely on random value all the decision making should be as natural as possible and make sense allowing the goals of the agent such is natural Institute is a project to have this emotional pipeline to allow NPC to have exp emotions mood enough personalities allowing them to be Livia and enhance the player experience but this time the challenge was to bring this pipeline to production and today on top of explaining it we will cover its adaptability to any experience and how to balance and debug it depending on of the needs of the designers but also on the experience so first what are emotions mood and

personalities depending on the paper you are looking at there are many definitions in this presentation we Define them in the following way so emotions are short-term feelings that evolve quickly over time like Joy distress and fear and mood is a much more long-term feeling that evolve slowly but smoothly over time like exuberance depressed and the threat and personalities overall defines the agent depending on the experience you create it may be either fixed or very slowly evolving over time like curiosity shyness and laziness so now uh what why would you want your NPCs to have Dynamic emotions moods and personalities what would this bring to your experience so first let's take an example with our Prototype game Wonder but without a motion animation or personality and mood

so in this experience the player is a little fury that you can see on the bottom left and give orders to this character Pino here we ask to use the book and we try to use it in the way you think is good however he did a shot into it so it was not a good use case and the player told the Pino about that but not quite happy about it um in this game yeah you know will learn basically thanks to this interaction if it's quite use case or not and being able to solve Quest and other things later and I would like you to focus a bit more on the character itself and the way he's expressing the different thing happening around him uh consider the work is always the same as there is not much viation and the face is just a little smile not changing much having some little uh of course animation for the action but nothing very uh outstanding so now let's have a motion animations mood and personality uh on for this demonstration and do the same thing we can already see that phenomo is moving much more energetically uh thanks to

this personality is into I hear he was hitting the book which is not correct and we can see that the reaction is also making more sense now and now I try to use a stick and we'll be able to be to see a bit more this personality motion like he's very in the exuberant kind of feeling now [Music] you can also see at the same time that the speech is uh changing based on this mood and personality he is quite happy about this uh being able to actually hit a ball with the bat uh overall personalities are a thing that evolve very slowly in this game like about five to ten minutes you may be able to move to one personality itself because it's very slow um I am now going to use the debug UI to quickly change the personality of the character and so um basically the little values when we have added based on the different personalities the characters in two here is a bit more reserved unit of personality and we are going to do

mostly the same kind of actions this year a little variation you can see already that uh the little reactions the ways expressing all the details mind that he may have on his face when he's encountering objects that he likes of dislike um is very different from the previous version ID and if you take a bit more attention you can see some differentiation based on the mood he's in two [Music] it's a bit maybe cuter with this personalities and here we try to use the dumbbells this time and I think it's quite a nutcase uh use case normally but yes player for some reason said it was neither a good nicer than lastly move to another question 19 this time we are going to show the mood so mood is basically here affecting a little bit the mood for the animation of the character it was not a simple easy to see during the demonstration so we have used the debugger to show a little bit more easily but I will come back to

that later um so now that you have seen that let's try to explain to you what is this emotional Pipeline with the different modules it has so first the immersion module it is based on the revised OCC model from the paper the processing model Revisited we have chosen this model because of its Simplicity and compatibility with game development which is not the case for a lot of these models for instance here her event is replaced by a game event and then it's just tree exploration based on conditions it is also a very well known uh Infamous model that worked really well with other mood models that I will explain later um so uh follow prototype Wonder we are actually not using the world graph uh we are using only the upper part of this OCC model so let's take an example with a popular game event uh first

um we assess if this game event is going to be a positive thing or negative thing for the agent for instance if it's hit by a goal it's going to be negative fitting except if he is a masochist I'm visiting a delicious cage it's going to be a positive feeling except if he has hiatus then based on the category of this event we can have consequence of events like for instance window board because of a goal or my closets are wet because of the weather because it's raining uh you can also have action of Agents like my own actions or the action of someone else and we can also have aspect event which is about hearing smelling or seeing something and lastly we'll have a list of emotions on the last row that we are going to generate based on the branch went into doing the analysis of this game event now is a popular game event um so the player this time has been hit

now hit the ball with the bat successfully so the agent is looking at the player and he's feeling happy for the player so it's a positive feeling because it's the action of another agent and we are going to advance this agent will Express a narration to other player let's say now that we have a windows that broke due to the ball that has been hit earlier by the player and this time it's going to be the consequence of the previous action as a player and the actual consequence is something bad we think the window broke so the agent is going to express distress towards this window in this way uh emotions are going to be generated in our experience this model can support up to 24 emotion in total depending on how much of these two you want to support emotion can be expressed in a lot of different ways it can have voice sound it can have fascia blend as I am showing here on top of other animations like shame or distress or pride and we can

also special animation and special speech when we are actually expressing these emotions um of course um this emotional module can be adapted to any experience as I said before uh even if it's quite big what you have to start with is actually it's a very basic and minimum version of this model that we think it is uh these three branches with actually eight emotions and from here uh you can actually add branches depending on what you want in your experience for instance if you are dealing with a known object to which the agent is able to get the liking or disliking based on the item features then it it can be interesting to add this and familial aspect Branch to have interest and discussed as a motion if interactions between AI agents themselves or AI agents and the player are one of the key of your experience then we recommend adding this related consequence Branch it's basically what we call a consequence of an action of an

agent so I will take an example to explain a little bit in detail what it is exactly window for instance earlier we said that the window broke due to the ball that has been hit by the player and at this time we express distress towards this pocket window well we know the agent knows that this ball has been hit by the player earlier so that's a player fault uh so we are actually going into this related consequence branch and express anger towards the player and thanks to this actually you can also have relationships Evolution between your agents themselves horse agent is a player based on this emotion that are being regenerated lastly if uai agents are able to prospect based on something happening around them the addition of the prospective consequence Branch will give great feedbacks so let's take an example the AI agents hear some noises in the stairs in the middle of the night the agent will feel fear that may be an

intruder may be in the house so yeah agent is courageous and decides how to check uh what is going on in the stairs so you check and see that actually his cat was playing with the goals and one felt of the stairs so he feels some relief or some kind of the actual consequence of this face is something positive so if we follow this model it's going to be Joy but it's not quite relief so we advise you in this case to actually add these four little branches below that will add the necessary distinction for instance belief in this case will be expressed because it is confident perspective and desiable consequence however uh when it comes to perspective in game uh it's not fun it's actually a very complex thing to do um in Wonder we are mostly using it on SIMPLE examples where it's easy to guess uh what may happen in the future for

instance prospecting from weather-based even like clouds are getting darker and darker so maybe it's going to rain or player taking an apple and going in the direction of the agent maybe it will feed the agent in this case so overall this model offers a lot of flexibility and allows the design now to basically adjust it depending on what they want to create while we have covered emotional Generations they are still two unknowns one is emotion parameters computation and the second is how to assess positivity of an event as your experience may already have many many game events the emotional model would like to listen to a few of them that you have listed up in the data table here we are listening to eat food or object and object visible uh they will have their event category a way to compute the emotional intensity and a way to compute the duration of these emotions and based on this

intensity function we'll be able to assess if this event is going to be a positive thing or a negative thing for the agent for instance hit by object is going to be negative because it's minus the hit speed and multiplied by the item weight and for heat food it's going to depend on the liking of the items that he is currently trying to hit um speaking about liking uh we also have this like this like system in our game and we are actually um generating liking and disliking at the same time that approaching everything emotions um so here the agent has been electrified by your fans so we are generating uh distress towards this uh this fence because not a pleasant feeling and at the same time we are going also towards this negative effect to the fence object and it can have an intensity and a memorable duration if you want it to be forgettable after some

times and on the top right you can see that currently our agent seems to like very much uh red apples okay so now I'll move upon to explaining the mood module which is a PID model so the PID model is a 3D space with three axis P A and D P for pleasure for arousal and default dominant so how pleasant is an emotion how intense is animation and how much control and influence the agents may have over situations these 3D models will have inside all the emotions that we are generating before are mapped and one octane for this model will represent one mood in this case where shame is we are the multiple thread and we are supporting a different mode as you can see on the left

in the center we have our default mid position and that is a little point that will move freely around this space uh while all these emotions are generated and yep and that's basically the PID model so we despise the complexity of a Swedish space we chose this model as it has one of uh of the few that works really well with OCC model like and simple at the same time um it allows a lot of expressibility and wide variations of mood and expression and it's important enough um so as I said sweetie may still be a problem so we'll come back to that later so everybody getting the updates of this PhD model um when an emotion has been generating like Joy depending on the intensity it will move at this point we move towards the joy emotion quickly or not and then there is no emotion anymore

um the agent becomes bored so the default mode finds a mood position and with point we'll go back slowly towards this development position as he got both involved now expression uh mode can be expressed in a lot of different ways it can for instance be expressed inside the decision making for instance having specific goals for specific moods also having specific set of actions you can also influence the way the The Voice we can manipulate the voice a bit based on this mood that we are currently doing in Wonder as well and we can also have a variation of Base body animation so here I am showing a single frame of our animation and we can see that based on the mood it's actually changing quite a lot and now I'm going to place a full animation and we can see a bit more in detail what are the difference between all these modes so right now is a in a fine mood so it's a bit not super

confident in his hit now his or Stylus is giving a big hit on the ground and when his exuberance actually jumping and hitting at the same time in further side it's just just a little tap on the ground very gentle um so these animations uh give a mood taste to the base animation that we had but they are not too strong variation uh as at the same time so they can play it well together um so the 3D PD model have some pros and cons and when it's come to adapt it to your experience you may want to get rid of this 3D uh while this really gives a vast variations of Expressions uh the more Dimensions the other ideas to debug and to balance and depending on the mood Expressions also assets can go quickly out of end asset cost so we have to find in Wonder at least we have to cut it down to 2D and what to choose between these uh three combination so inside this model there is one key axis

pleasure pleasure is basically the separation between what is a positive emotion and what is a negative emotion so it's a very important axis to have a nice evaluation of our game in expression so we are actually going to look at Roswell or dominance and choose between one of them and to make the choice what is a nice nice expressibility in their ways we are going to take a look at our generated emotions list what we can see in one case is that most of the emotions are actually in the original positive space so we are going to have a really hard time to go into the negative part of the horizontal space uh in this case we think that ozone is a less important axis and then we decided to keep pleasure and dominance for our 2D space but may not be the case for your experience we are to adapt of course these mood names mostly keepings a plus names

and here we are we have our 2D PID model so it has now become a DP model yeah uh we still have to put back our emotion from 3D to 2D so we check the official list of position for this emotion inside the PHD space from the paper and what we got is this location in the the cubes find the 2D space um we can see that most of them are overlapping and not well positioned the position of them is not very well balanced in the space um well it makes sense for psychology and all this research we opened exact humans or this kind of thing but when it comes to game the most important thing is to have a lot of variation of expression and to have the overall experience balance so we decided to actually post all this emotion to the Border in in the square and that's our

new mood space we could have done also in a circle around the center if we wanted to and here now I'm showing our experience with the UI showing the current mood how it evolves based on the different emotions that has been generated we can also see the emotion model at the top our CC model and we can see that right now it doesn't feel like super happy and it is in a hostile mood especially because the player is actually not super nice to him I think it's going to be visible now with the way it's working now is not super friendly however yeah based on on now he did a successful action and the player was happy so now we are able to go back a little bit inside this exuberant mood because that's how this mood and emotional generation happen in our game um and we hope it was nice so now personality module

as you can see it's a very simple structure it's just UTD parameters between zero and one unlike laziness curiosity and honesty and why it's super simple uh it can have actually a broad way of expressive expression inside your game um you can have different goals available depending on the personality or the way the actions are done also a bit different on the action available can also change for the planning phase for adding animation we can also have also strong variation for instance in our walking cycle based on the personality we are into right now as a animation is changing quite a lot the way of speaking as I said before is changing based on the personality is currently into and as I've done in GT 2019 we can also have this default mode position uh that change depending on the personality you are into like if you have a angry kind of personality you may want

to put your default me position more in the All-Star in mood so that when the agent got bald it will go slowly to back towards this hostile mode um now um when it comes to personality and you want to add personality to your game we advise to First actually choose where you want to express them and where they will have influences if it's just in the decision making like in GT6 2019 for my talk as any number of personalities should be manageable as it is only when it is only design cost and majority of the case it's not going to be asset related normally but if it's about giving inferences to animations speech or asset related applications then it can quickly go out of hands and that's the case for Wonder actually uh in Wonder we have eight different personalities and that's that's quite a

number um personalities influences both base animation of world idle reactions but also the way the agent is speaking um so that's a lot of assets to create uh for instance we have eight personalities with four modes and one base animation as well so this make a total of 33 animations to create that's a lot that's way too much for what you can handle so we decided to at least try to cut this number down a bit so we decided to create what we call personalities principles for them that will go back to a few of these personality parameters together and thanks to this we are able to reduce the number of Animation from 33 to 17. it was enough in our case of course decision making I can use this personality principles if it wants but you can also use these eight personalities as before so there is no

problem with that okay now let's move to troubleshooting and speak about our different debug's tools and tweaks and the balance tools that we have created foreign so the first tool we have is basically personality debug we can just click on this UI and set the character in a specific personality right away so if you want to test something very quickly it's very useful in a similar manner we have this uh um mood space that build UI where we can click into and set our character to be in a specific mode and specific personality whenever we want so that we can test all the possibility easily we can also see really right now that mood heat map that is updated during the World Experience allowing you to know basically how the users are playing your game and if

for all players for instance the Moon is always in the same area is not able to actually to move in all the space which is something you may want to know and try to fix we also have a personality history that allow us to know when a personality changes happened what is the source and how they evolve we also have emotion history that released the different parameters this emotion had when they occurred and from what source and uh at the end we have the most important tool that I will explain now the emotion of all information that basically computes inference score of each emotion on the mood during your playthrough so that's the table you can see at the bottom so for each emotion we'll have the number of occurrences to average intensity and the average duration it has had during the whole place and from that we are going to compute an inference score which is just the sum of

this intensity multiplied by duration for all this emotion so how can we use this tool um in one specific case one of the most uh known problem are difficult to balance problem is the mood is always in the same area like no matter what player plays it's always there and it's very hard to get away from it well if you look at this table now we can get a lot of information from it we check for instance first what is the highest influence score in motion and we can see that Joy is actually influencing at least twice more than the other emotion on the mood so maybe it's too much in in this instance in this case we are going to investigate joy and see what may be the problem you consider the number of occurrencies of this emotion is actually almost a double to the other emotion so maybe we can try to reduce this number of occurrences but

sometimes it's not possible because it makes sense in a game a design point of view so we can try this time to reduce its average intensity so that it better use this range from 0 to 1 instead of always being very high sometimes it's still not enough uh it doesn't make sense so you can do it you can do a similar thing with the duration and try to lower it a bit that does less influence on the mood overall but if everything makes sense for your design then maybe it's the other image on the counter emotions are not influencing the mood enough in this case you want to try to boost either the number of times they append or the intensity or the duration of them and at the end yeah if you are able to get an influence call that are mostly balanced between all your emotions or a bit more positive or a bit more negative and you can do it easily and understand easily thanks to this uh about two but you have to uh to aggregate your data with many

players as players of different personalities and way of playing so that's it for me today uh thank you for watching and if you want to contact me uh here are my informations I have a great GDC [Music]