Developing a system for interactive drama requires finding the optimal point on the scale between the extreme high level of an animation movie, where everything is predefined, and the extreme low level of a hypothetical ideal AI or A-Life system that only authors the smallest atoms of behaviour and where all results are emergent.
In a realistic present-day situation, building autonomy into your characters boils down to designing a system that allows these characters to choose from a list of pre-defined actions. One side of this problem is the selection mechanism, the other side of this problem is the definition of the actions.
The actions can be be defined on a low level (walk, breathe, wave, pick up) or on a high level (walk to the wall and pick up the key and wave when you’re done). The lower the definition, the more emergent the behaviour is. The higher, the more the behaviour will make sense. The selection system will need to be designed to deal with either one.
Actions defined on a higher level are actually sequences of actions defined on a lower level. So strictly speaking, we could have two selection systems: one to select from a lower level and one from a higher level. These systems could work together or alternately. The latter requires yet another selection system that decides when to apply the lower level, more emergent, behaviour and when the higher level, more defined, behaviour.
Posted on May 23, 2006 at 9:43 am
Perhaps this distinction can be mapped unto another desired distinction in the behaviour of autonomous characters. Namely the distinction between behaviours when the characters is on its own and behaviours when the character is in the company of other characters. For the sake of drama, a higher level definition is required for the latter.
Being alone or being in company does not have to be a binary situation, however. It could be a scale going from being completely alone, over having some objects around you and being among other people to being among friends. Perhaps the selection between low level and high level actions can slide accordingly: as the character is more alone, there is more chance for low level behaviour. This chance decreases as the “social level” of the situation increases and more well-defined behaviours are desired.
At the highest level, these behaviours probably need to be defined for two characters simultaneously. Especially when these characters are interacting with each other (playing a game, talking, hugging). It’s kind of cute to think of a selection method for behaviours ranging from total randomness in the depths of solitude to orchestrated in pairs when together with a friend.
Perhaps this is also a type of stylisation that could be interesing artistically.