This paper describes a software system called "Emergence" that displays three dimensional, computer generated environments and autonomous, animated characters, in real-time. The users, or participants, are represented as "avatars".
Through a scripting language one can use techniques of Artificial Life to specify behaviors and relationships between characters and objects. This system allows for the creation of muliparticipant virtual worlds that are "alive", responsive and interactive.
We examine the role of the avatar and the relationships between the avatar and its human counterpart as well as relationships between avatars and artificial life forms.
We are told that in the not so distant future we will spend hours immersed in three dimensional virtual worlds. These worlds will include "avatars", virtual representations of ourselves in the form of computer generated characters. Our soul, our consciousness, will somehow be embodied in an avatar. The avatar becomes our other body, another container for our spirit.
What is the relationship one has with his or her avatar? Do we control it like a puppet, or is an avatar like a child, containing the spirit of its parents, but with its own set of behaviors? What part of "us" is in our avatar? Is part of our soul in this computer generated character?
The psychologist C.A. Meier, equates the soul to our most intimate identity, our conscious ego (Meier 1986). When writing about the localization of consciousness Meier refers to the observations of Mary Kingsley, an ethnologist who lived with West African tribes in the 1890's.
Kingsley described the West African belief that a person has more than one soul and that there is a certain type of soul, called the "bush soul", that dwells within a wild animal of the bush. A person's bush soul lives inside an animal though that animal also has a life of its own. (Kingsley 1899). This implies that it is not necessary to leave one's body to experience another world.
An avatar could serve as a place for the bush soul to dwell. The avatar carries a person's bush soul into the virtual bush by following the guidance of the person attached to it. But it is also "alive" with is own set of behaviors. In this world interactions occur and relationships are developed with forms of artificial life as well as with other avatars and their bush souls.
This formed the inspiration for my current work. In order to create this kind of virtual world, it was necessary to first build the underlying framework that would support a "living" virtual environment. This was accomplished with a team of computer science and design students who assisted in the development of a software system called "Emergence".
Emergence is a PC-based software system that supports an active, responsive, networked, virtual world. In this system, environments and their inhabitants are rendered in real-time as three dimensional, texture-mapped polygons. The users (called “participants”) are represented as 3D avatar models. Sounds such as voice, music or ambient effects are linked to objects and characters in the environment to enhance the sense of life and space.
Emergence supports multiple camera viewpoints. Each inhabitant, including the avatar, can be viewed from a first or third person perspective. We have found it most effective to attach a camera to the avatar with a certain distance and lag. This third person perspective allows one to observe the avatar while attached to it. There are also free roaming cameras, allowing exploration of the world independent of a participant's avatar.
In addition, we have developed a client-server model that enables the networking of environments. The server handles changes to the world geometry and movement of objects, sending updates of the world model to the clients. Clients render user-dependent views into the world, and receive user input.
Our primary focus is on the design of movement as it relates to the animation of avatars and other forms of artificial life. Therefore, one of the major requirements of the Emergence system is to handle hierarchical motion data from articulated 3D models, including motion-captured animation, since this is most important for the impression of life and interaction within the world.
To do this, we have created a production pathway that converts 3D models, including textures, materials and hierarchical animation data into a form that is read by our system.
Fluid and "natural" motion take precedence over realistically modelled characters and environments. We are creating living, abstract worlds. The design of characters and other environmental objects is derived from their behaviors and their style of movement.
We have also developed a scripting language that allows one to design behaviors and relationships between characters and objects. Using techniques of Artificial Life, the unique behavior of virtual inhabitants emerge from a set of parameters that are defined through the scripting language. In the case of the avatar, its behavior is combined with joystick control input from the participant.
The computer-controlled inhabitants of the virtual world are designed with interactivity in mind. Each of the inhabitants or agents of the virtual world has a set of parameters that govern their behavior towards other inhabitants. Using the scripting language to manipulate a set of parameters, an agent can be endowed with "feelings" towards any object in the world. Feelings such as love, like, dislike, fear, hate or indifference drive the agent's movements and affect an agent's reaction to an inhabitant when in its vicinity.
As an example, a character may like an avatar and follow it around, but it may also fear another character and will flee when it sees that character approaching the avatar. In addition, it may be part of a group and will occasionally go off to join its group. As in real life, a complex social environment can be achieved from the interaction of simple agent behaviors.
In order for agents to "see and hear" other inhabitants and maneuver through the space, each agent has vision and sound sensors and a range of individual characteristics that control features such as dynamics. All parameters can be customized for each agent creating diversity within the world.
Any inhabitant can also be a member of a group. This allows for the development of emergent group behaviors. Emergence occurs when, acting under local rules and local information, a collection of individuals appears to act as a centrally controlled group. Examples of emergent behaviors are abundant in nature. Flocks of birds that appear to be acting under a single control as they collectively meander or schools of fish that appear to be guided along the same path are two examples.
In our world, emergent group behaviors include flocking, following and fleeing. Agents belonging to a group still retain their individual feelings towards other inhabitants.
In addition, an inhabitant's behaviors and feelings can adapt over time. For example, a participant's avatar can harass an agent that likes it (by getting in its way and following it closely), causing the agent to gradually dislike the avatar. Or a character could come to life only after an avatar interacts with it. As in real-life, feelings can change based on interactions with certain characters or due to time-based events.
Procedural behaviors applied to articulated 3D models proved to be a powerful method for invoking the sense of an alive, complex, social and interactive environment.
Another strong area of interest is in the exploration of new forms of Performance Art that take place in virtual worlds. As part of this exploration, we have recorded substantial amounts of motion capture data of performance movements and other human motion.
The motion data is applied to various 3D models and can then be layered with a virtual performer's overall set of behaviors, creating complex, somewhat unpredictable performances. Through scripting, a performer can react and interact with the audience and other performers in ways that are not possible in real life.
The Emergence system was developed to allow for the creation of artistic works, such as "The Bush Soul". Emergence provides a creative environment that encourages one to go beyond the rigid format of commercial video games with their uninspired designs and simplistic focus on violent, "kill or be killed" behavior.
With this system we are experimenting with forms of communication that rely on symbolic gestures, movements and behaviors. Our focus is on motion, the "life" of the environment, and the role of artificial life in the creation of an art form which includes the interactive experience.
Many cultures believe that everything has some form of a soul. We carry this idea into our virtual world where every object is instilled with some form of artificial life. Driven by its internal code or in response to its environment, an object, for instance, may change its shape and color, make a sound, begin to move or initiate some type of interaction.
In this virtual world relationships can be formed between all elements. Movement and interaction enhance the emergence of a rich environment populated by engaging inhabitants. An intriguing place for a wandering bush soul.
The first installation of "The Bush Soul" was presented at Art Futura in Madrid, Spain in October 1997. The piece will continue to grow and evolve.
The software development is partially funded by a grant from Intel Corporation.
Kingsley, Mary 1899. West African Studies. London: Macmillan and Co., pp. 199-209.
Meier, C.A. 1986. Soul and Body. San Francisco: The Lapis Press, pp. 268-277.