Posted by Michael on June 20th, 2006, in Development
Attention span is a property of an actor. It reduces every time the actor interacts with the same object as previously and is reset to maximum when the actor switches objects.
Actors will prefer to interact with objects that they like. Attention span prevents obsession with a single object and forces the character to interact with another object once in a while.
There’s a problem with this. If attention span is reset to maximum when the actor picks a new object, it will go back to the previous object whenever it needs to make a new decision. Because it likes that object so much.
So you’d see a girl playing with a ball in different ways, then picking up a stick and throwing it away, after which she will play with the ball again.
Of course we always have a chance of break-up which would make the girl lose her fondness for the ball and thus allow her to choose to interact with another object. But break-up should remain relatively rare for dramatic reasons.
If attention span were to work for objects in a similar way as fascination works for opportunities, we would see attention span for a specific object drop as you keep interacting with it. When you’re done interacting, attention span would rise back to maximum slowly.
This sounds like attitude to me. Currently, attitude keeps track of whether the actor prefers to make a relationship better or worse. It’s a boolean value (good or bad) and it’s connected to the relationship with an object. We could expand attitude so that it can express how much you like to make the relationship better or worse.
Here’s how that would work:
The normal level of attitude is the maximum. When you interact with an object, your attitude about this object decreases. All of this in absolute terms while good or bad are signified by plus or minus and do not change in this operation. Attitude modifies your intimacy with an object temporarily. In other words: you get bored, even with objects that you like. While you’re interacting with another object, the attitude about the previous one slowly improves.
We will have to find a careful balance between attitude and decrease of intimacy through seperation. The latter lasts a lot longer and should thus be invoked less frequently.
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Posted by Michael on June 19th, 2006, in Development
This is a summary of my earlier musings about hostility and intimacy.It leads to the introduction of attitude which allows an actor to choose actions that make relationships better or worse.
Each item in the gameworld has a list of opportunities. Those are interactions that an actor can do with them. Each opportunity has an intimacy value associated with it. This intimacy value expresses the intimacy of the relationship that is desired to perform this interaction.
Items can be environments, inanimate things and actors.
An object is an item that advertises its list of opportunities to all actors.
Each actor has a relationship with each object which is expressed in a level of intimacy. This level can be positive (friendship), negative (hostility) or neutral (indifference).
About each relationship, every actor has an attitude. This attitude is the way in which the actor plans to continue its relationship: towards more or less intimacy.
Relationships, including their intimacy and attitude, are shared by both members of the relationship. For reasons of simplicity, asymmetrical relationships do not exist in the world of Drama Princess.
Each actor also has a degree of enthusiasm. Very enthusiastic actors will choose opportunities with intimacy level that are far removed from the intimacy of the relationship. If the attitude about the relationship is positive, the actor will choose an opportunity of a much higher intimacy level. And vice versa. A less enthusiastic actor will be more careful and choose opportunities that are only slightly higher or lower than the intimacy level.
Every interaction impacts the level of intimacy of the relationship. Choosing an opportunity with a lower intimacy level than the relationship will decrease the relationship. And vice versa.
The bigger the difference between the enthusiasm values of the actors, the bigger the chance of a break-up. At least in good relationships. In bad relationships, there is no chance for a break-up. The relationship will simply get worse as actors keep interacting with each other.
Seperation of an actor from an object will cause its relationship with this object to slowly evolve towards neutral. I.e. a bad relationship will get better, a good one worse.
Shock is an external event that can cause a break-up, disregarding the level of relationship.
A break-up resets the relationship to neutral intimacy. When the relationship is more or less neutral, the attitude can keep changing. Only when the relationship has started to develop in a certain direction, will the attitude be fixed in that direction.
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Posted by Michael on June 19th, 2006, in Development
Every item in the game world that can be interacted with (i.e. every “object”) broadcasts a list of opportunities to all actors. The actors can then choose to do one of these interactions.
Sometimes, however, the object might only want the interaction to take place in certain situations. E.g. the interaction may only work if the actor is sitting down. Or if the actor is a young child. Or if it is raining.
For this reason, every opportunity has a condition that needs to be fulfilled before the character can choose it as a goal.
In general most opportunities will be available for most actors. So the condition should be optional, to minimize processing time.
The condition should have an open format that suits any situation.
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Posted by Michael on June 19th, 2006, in Development
This is a stream of consciousness about the possibility to reduce the intimacy of relationships and how shocks are triggered in the Romanticism model. I will post some clearer conclusions in a future post.
One thing still bothers me with the Romanticism model as it is now. And this thing rises to the surface as soon as I start thinking of a Drama Princess actor as an avatar for the player. It’s the fact that actors are “programmed to be nice“.
Read on…
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Posted by Michael on June 19th, 2006, in Development
When a Drama Princess actor interacts with an object, its intimacy with this object increases. The actor starts the game with predefined intimacy levels for categories of objects and certain individuals. From there the intimacy can grow.
Up till now, I’ve always thought of the maximum (or optimum) intimacy to be the same for all objects (with perhaps a crude differentiation between inanimate objects and characters). But allowing the author to define an optimum (final) level of intimacy for each character would help craft the narrative by allowing certain characters to fall in love with each other and others not.
For the sake of playfulness, this author-defined maximum initimacy does not need to be fixed. Perhaps if they work on it hard enough (especially in interactions with the player’s avatar), characters could raise this maximum, allowing for unexpected fondnesses.
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Posted by Michael on June 17th, 2006, in Development
Perhaps underacting is a form of stylisation that can help us limit the amount of hand-crafted character animations that we need. For this purpose, I studied Humphrey Bogart’s and Lauren Bacall’s acting in Key Largo with the sound off.
Here’s some observations that don’t necessarily apply to underacting as such but perhaps to human behaviour in general.
A very inspiring thing regarding idle behaviour -which came up a few times before in this journal- was that I noticed that an real actor doesn’t have a neutral pose. He does a certain motion and then freezes in the end pose of this movement. Later he does another motion that ends in another pose.
This could be translated to virtual actors if, rather than blending out of and into a neutral stance in between actions (which most games, including The Endless Forest, default to), at the end of an action, an idle animation is played that pauses in a certain pose (with a loop for subtle motion so the characters don’t look frozen). Then when another action is chosen, the idle motion continues to play to its end while the action animation blends in. In theory, there would still be a neutral stance at the end of the idle motion and at the beginning of the action, but it would disappear in the transition, or at least be displayed only for a very short time.
Walking speed is used for expression: slowing down means attention, speeding up means enthusiasm or urgency.
In 8 and in The Endless Forest, the character walks fast if the target is far away and slow if it is closeby, thus ignoring the expressive potential of walking speed.
When something happens, e.g. when someone talks to the actor, the actor’s body does not respond immediately. He sits there motionless and we think he’s listening. Only a little later does he turn his head towards the event.
When a third person arrives, the actor looks at her and steps back a little to make room for her in the circle of the conversation.
When the actor looks down briefly during an interaction, it expresses thought or (mild) embarassment.
When an actor stays in the same pose while another is talking, he seems to be listening, even if he doesn’t look at the other. In fact, not looking seems like he’s listening more intently.
When several actors are in a scene, the viewer pays attention to the one who does the action, more or less ignoring all the others.
Bogart almost never holds his head straight. It’s always a little cocked. At least when he’s sitting or standing still.
When a woman touches her hair in the company of a man, it expresses romantic interest.
An actor can be standing still until he is spoken to. Then he moves into another pose (hands in back, e.g.).
When a shock happens, the actor changes pose as well.
When the actor is still in a pose and wants to move, he will first look elsewhere.
The actor stands still when listening and wobbles when talking, especially when starting to talk.
Just staring at somebody without moving and without facial expression expresses hatred. When the eyes are wide open, it expresses aggression.
Unrelated to actors but interesting nonetheless: a slow ventilator expresses heat. 🙂
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Posted by Michael on June 16th, 2006, in Development
The core of Drama Princess is playing canned character animations. This is a very artificial situation. Human actors put a lot more variation in their performance. They never really do the same things more than once, certainly not within the course of a single play. Virtual actors, with the current state of technology, are not that versatile.
The risk exists that, despite our efforts, our Drama Princess actor will still seem artificial and robot-like. We could compensate to some extent by making large amounts of animations for each character. But that costs a lot of production money, takes a lot of production time and increases the file size and probably the memory requirements as well. And ultimately, given the nature of the system, the actor will repeat its motions once in a while anyway.
It looks like repetitive behaviour is a fact of life when working with virtual actors. The question now becomes, how do we work with this limitation? What can we do within this limitation to maximize believability.
One solution could perhaps be found in stylisation. Certain forms of theater have embraced such stylisation. The Commedia dell’Arte is a well known example that inspired modern artists like Meyerhold to develop an extremely stylised form of acting. Since the vocabulary of such acting is limited, it could serve as a model for a virtual actor system.
The more expressive animations are, the more you will notice when they repeat. If animations are subtle, however, you will be far less likely to notice the repetition.
Perhaps the underacting that was typical for Hollywood films in the 40s and 50s could be inspiring as well. Humphrey Bogart and Lauren Bacall are masters in acting out passionate feelings while hardly moving a limb or batting a lid. We’ll have to study their work a bit to find out if they are really immobile or if there is still a lot going on that is possibly far too subtle for any virtual actor.
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Posted by Michael on June 16th, 2006, in Development
I made a first little text-based test with a very limited version of the Romanicism idea.
Some observations:
Despite the randomness, the behaviour in the beginning is (almost?) always the same. When shocks start happening, more variation occurs. So perhaps we shouldn’t wait until a relationship gets saturated to generate a shock. Perhaps mild shocks as the relationship develops, would appropriate.
Distributed “mini-shocks” would also allow the actor to express its feelings once in a while.
At some points, the girl seems to cycle through the same set of behaviours. So we may want to add a bit of randomness to the restoration of fascination.
The girl is always doing something. This will probably make her look unrealistic or nervous. In the romanticism concept, this would be solved by adding more opportunities to the environment (in this case, the room). But that would still make her choose between the ball and the room and might still make her interact with the ball too much. Maybe we should introduce a new element: idle behaviour. Just standing around, doing nothing much, looking at objects, or staring in space. This could be influenced by a variable like comfort. The more comfortable an actor feels, the less it will be inclined to choose an opportunity as a goal and the more it will choose to do idle behaviour. This could be used to help define the actor’s personality (fixed) or its mood (dynamic).
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Posted by Michael on June 14th, 2006, in Development
This is basically a new version of Consumerism, named after a suggestion by Patrick. I’ll try to be brief for the sake of clarity. The details can be dealt with in seperate posts.
Drama Princess is by no means an attempt to recreate human life. Its only purpose is to model autonomous behaviour of characters in such a way that the user can imagine things about it. Rather than realistic or even believable, we want our characters to be suggestive and inspiring.
A character that interacts with something is called an actor. The (potential) target of such an interaction is called object. An object can be another character, an inanimate item or an environment.
Intimacy is the level of the relationship of an actor with each object in the world. The actor starts the game with intimacy values for categories of objects only. When it interacts with an individual, it creates an intimacy value for this object. Each interaction with an object changes this intimacy value.
Enthusiasm defines attention span and the eagerness with which an actor will try to improve its intimacy with an object. A very enthusiastic actor will switch more easily between different objects to interact with. Enthusiasm remains the same throughout the game (unless aging is part of it).
The author uses intimacy and enthusiasm to define the personality of each actor.
All objects in the game world have a list of interactions that actors can perform with them, called opportunities. Each actor continuously collects all opportunities in its vicinity and chooses one of them as its goal. It will attempt to achieve this goal by performing a sequence of actions.
All activity in the game is interactivity with objects.
Solitary activity is defined as interactivity with the environment.
Every opportunity fits with a certain level of intimacy. An actor will select an opportunity as its goal based on its level of intimacy with the object that broadcasted the opportunity. Enthusiastic actors will be more inclined to choose an opportunity that is more intimate than fits their relationship with the object. Less enthusiastic actors will choose one the fits more closely.
Every time a goal is achieved, the actor’s intimacy with the object that broadcasted the opportunity is altered. Most of the time, the intimacy will improve (the reasoning being that interaction with objects increases familiarity with them). But the bigger the difference between the level of intimacy of the opportunity and the level of intimacy of the relationship, the higher the chance of a negative effect (because the other character does not want to be rushed when you do something that is too enthusiastic or because it is disappointed when you do something that seems too distant).
When an actor is seperated from an object, its intimacy with this object goes down over time. Intimacy is a value that is shared by both participants in the relationship (for the sake of simplicity, they are always equally fond of each other).
When intimacy with an object has exceeded its maximum value, the chance of a break-up will grow. When this happens, the intimacy between the two will be reset to a lower level.
When intimacy drops below zero, actors will be more inclined to choose opportunities that are even lower (i.e. you want to reduce the intimacy with your enemies).
Since interactions alter the intimacy, the preference of an actor for opportunities will continuously change. To completely exclude the chance of an actor selecting the same opportunity twice in a row, fascination for the opportunity drops instantly after the goal has been achieved. Over time, fascination reaches a normal level again.
To ensure that actors don’t keep pursuing goals that they cannot achieve, fascination of the opportunity that has been chosen as the goal decreases over time. At some point other opportunities will seem more appealing and the actor will choose a new goal.
The concept of shock ensures that characters respond to sudden events. A shock will replace the global list of opportunities with a limited list of responses to the event, out of which the characters can choose.
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Posted by Michael on June 13th, 2006, in Development
The Oz papers tell me that expressing emotions is very important for the characters to be believable (which is something they in turn learned from the Disney animators). And my Body Language book tells me that when people like each other, they start imitating each other’s body language, at least in the early stage of the friendship.
So it seems that it would help believabilty if characters would express the effect of an interaction with each other through body language (rather than by having plus or minus signs float above their heads as in The Sims). So that when the interaction (i.e. “achieving the goal” in Consumerism speak) results in a positive effect on the relationship, the characters briefly imitate each other’s posture. Or when the effect was negative, they purposely don’t.
Perhaps the animation sequence that is played during such an interaction can end in a certain pose (it has to go back to some neutral stance anyway) which is an invitation for the other character to either imitate or ignore.
Even if this would look artificial, it could still be powerful. I only wonder whether this can be read by the player (either consciously or subconsciously). I know of only one other game that uses imitation to express relationship: in Animal Crossing a character changes into the other character’s clothing to express fondess. This is very clear to the player.
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