DigitalSpace Papers
Inhabited Virtual Worlds in Cyberspace
(book chapter, JC Heudin, editor)
Bruce Damer, Stuart Gold, Karen Marcelo, Frank Revi
Contact Consortium
343 Soquel Ave, Suite 70
Santa Cruz CA 95062-2305 USA
contact our Webmaster

Bibliographic Reference: this is a book chapter by Bruce Damer, Stuart Gold, Karen Marcelo and Frank Revi featured in Virtual Worlds, Synthetic Universes, Digital Life, Jean-Claude Heudin Editor, Perseus Books, 1999, Reading MA USA, (New England Complex Systems Institute Series on Complexity), pp. 127-152.

If you have comments on this chapter, please email comments to Bruce Damer via our Webmaster.
Chapter Contents
I. Roots of the Medium
II. Technical Underpinnings of Inhabited Virtual Worlds
How to Build a World?
III. Example Virtual World Projects
The Social Matrix
The Role of Alife in the Inhabited Virtual World
Sherwood Forest Town
TheU Virtual University Architecture Competition
Biota’s Nerve Garden: A Public Terrarium in Cyberspace
IV. The Long View: Virtual Worlds as a Primordial Soup for Society, Technology and Life on Earth
The Future of the Medium
Prospects for a Cambrian Explosion Inside Cyberspace
Simulacara to Nanocara


In his introduction to this volume, Jean-Claude Heudin defines Virtual Worlds (VW) '…as the study of computer programs that implement digital worlds with their own ‘physical’ and ‘biological’ laws'. He cites two building blocks, VR (concerned with the design of 3D graphical spaces) with ALife (focused on the simulation of living systems) and forges a synthesis in VW, which is then 'concerned with the simulation of entire worlds and the synthesis of digital universes.' This chapter will suggest a third component to the concept of Virtual Worlds, that of the Virtual Communities (VC) that form in and around them. We could refer to this type of environment as an Inhabited Virtual World (IVW).

In this chapter we will briefly review the historical and technical underpinnings of IVSs and then suggest a future role for Alife within the online virtual world medium. We will then illustrate some extensive virtual world projects undertaken by the authors’ organization, the Contact Consortium, which illustrate principles of emergence in virtual communities and the structures of their worlds. It is useful to point out that the Consortium has its roots in networked learning and contact experiments, so our worlds have a definite pedagogical bent. We will conclude with some short and long term views of where virtual worlds, Alife and virtual community may be headed.

I. Roots of the Medium

Virtual community finds its technological roots in the earliest text-based multi-user games such as Space War that was a popular application within the early development of Unix. Continuing this trend was the development of UseNET, LISTSERVs, MUDs, MOOs, IRC and conferencing systems like the WELL in the 1970s and 80s (Rheingold 1993), and the World Wide Web and its many progeny in the 90s. The merging of text-based chat channels with a visual interface in which users were represented as 'avatars' occured first in Habitat in the mid 1980s (Benedikt, 1991) and reached an important watermark with the launch of the 3D Internet-based Worlds Chat in the spring of 1995. Strangely, one would suppose that the rise of 'inhabited' 2D and 3D visual spaces in cyberspace would have been heavily influenced by the prior example of Virtual Reality (VR) systems and be closely connected with the development of the Virtual Reality Modeling Language (VRML), but this was not the case. Inhabited Virtual Worlds and their communities drew primarily from their roots in MUDs and text-based real time chat systems and utilized the power of existing 3D rendering engines developed for gaming applications such as Doom and Quake. VRML has had little to no influence except as an occasional model interchange format and is used in few IVWs with large user communities. IVWs do not take advantage of the full immersion and special devices of VR systems but instead concentrate on running effectively on a large range of consumer computing platforms at modem speeds.

II. Technical Underpinnings of Inhabited Virtual Worlds

Since 1995, a dozen technologies for IVWs have hosted hundreds of thousands of Internet visitors. Each platform represents a distinct vision of what kind of experience a virtual world should offer its communities. This is the 'early adopter' period in the development of the medium and we expect this 'Cambrian Explosion' of approaches to continue for some years. IVWs are still seeking to justify their existence financially, and provide reasons for users to return to the spaces. Some have chosen the game play model. Ultima Online, Quake and other multi player gaming systems have found success by providing a highly structured environment with quests for players to embark on, skills and tokens to acquire, health to endanger, or clans to pit in combat. Social creative virtual worlds, such as WorldsAway or Active Worlds, have relied on inhabitants to build up the community structure, economies, and very content of the spaces. This chapter will focus on these social creative worlds due to their interesting emergent properties and inherently more open architecture. It is this openness that makes these worlds more likely to incorporate metaphors from biology.

How to Build a World?

The technology involved in serving up an inhabited virtual world experience is extensive and impressive. From robust client-server architectures, to streaming 3D object models, to tricks dealing with latency, to citizen authorization and crowd control, and finally to databases managing and mirroring hundreds of millions of objects and thousands of users across networks at modem dial-up speeds, IVWs represent one of the great architectural achievements of computing. We invite you to view the image of one particular cityscape, contained in the color plates section of this book. This 'satellite view' of the Alphaworld cityscape is actually an artful processing of the database of 3D content placed down by some of 200,000 users in the first 18 months of operation from the summer of 1995. Currently over 50 million objects occupy this space, which can be visited by users with ordinary consumer computers running on slow (14.4 or 28.8 KBPS) modem connections.

The literature surrounding virtual world architectures, community development (Damer 1995, Damer 1996, Damer 1998, Powers 1997) and avatar design (Wilcox 1998) is comprehensive and growing, so we will not treat this subject further here.

III. Example Virtual World Projects

We will now describe some of the projects in virtual world cyberspace undertaken by the Contact Consortium and its Special Interest Groups (SIGs). These worlds and their resultant communities of interest, were all hosted on line for a general Internet audience between January of 1996 and the fall of 1998. Due to the origins and charter of the organization, these worlds have a distinctly pedagogical bent. The three projects we will review include:
  1. Sherwood Forest Town: A Virtual Village on the Internet

  2. TheU Virtual University Architecture Competition

  3. Biota’s Nerve Garden: a Public Terrarium in Cyberspace

Before diving into these worlds, we should consider some of the elements of an effective social matrix needed to make any project a success. Following in the footsteps of successful community and frequent visitation of worlds, a rich set of biological metaphors could be introduced. Artificial life can both imbue inhabited cyberspace with new meaning and new interest and can also serve as a technology cornerstone in the delivery of the experience to users.

The platforms used

At the very birth of this medium, there are a variety of platforms that can support inhabitation over standard Internet connections on consumer computers. There is an exhaustive treatment of these platforms at the 'Avatar Teleport' on the web at We will take a quick review of the major platforms below:

The Social Matrix

In addition, perhaps more important than the technology of the IVW platforms is the social engineering and people management that strengthens the tenuous web of interactions and shared experience that create communities compelling enough draw users to return to the spaces. Visually impressive 3D effects are not necessarily conducive to good social interaction, as successful 2D environments like Fujitsu’s WorldsAway or The Palace have shown. We are only beginning to understand which social user interface affordances promote the development of effective virtual communities. Features such as text or voice chat, private channels, friends lists, muting or expulsion, gift giving, voting and associations, town charters, gestures and many more features are only part of the picture. Best laid plans can do little to encourage or discourage the emergence of social leaders, dispute resolvers, gossip mongers, goodwill spreaders, gatekeepers, community disciplinarians, thieves, abusers and vandals.

Figure 2: A head-banger attacking a user in Onlive Traveler’s Utopia community
Click on this image to bring up the print resolution version

Figures of legend, social norms, and virtual world equivalents of urban myths all rise to color the character of virtual communities. A good reference and more rigorous treatment of these themes can be found in the works of Harvard researcher Sherry Turkle (Turkle 1995). In our three and a half years of anecdotal observations, we have witnessed many fascinating events and heard an array of incredible stories:
  1. An endless series of weddings between citizens who are getting married for real or treating their cyber betrothals as a whole new form of social interaction (figure 1).

  2. Gangs of head banging and boom boxing teens terrorizing Traveler worlds and being recruited into a newly devised team of avatar football players (figure 2);

  3. An eight month old infant using the microphone to chew and suck his way into contact with avatars in Onlive’s Traveler

  4. Rabbis and Zen Buddhist monks resolving a dispute between spiritual centers built too close together and learning valuable lessons from each other in the process;

  5. The memorialization through virtual gravestones for community citizens, dying either in real life and figuratively (due to evictions from worlds). For example, the death of Princess Diana was marked in cyberspace worlds by flower-bedecked monuments hours before Britons and the rest of the world woke to the news;

  6. Other social structures emerge in world including societies, elected officials, and police departments pursuing vandal gangs of former police officers;

  7. Face to face meetings of virtual worlds citizens occur and either connect the bonds more securely or shock people with the alternate realities of their real life selves (figure 3).

The Role of Alife in the Inhabited Virtual World

The unique theme of this volume is to investigate how concepts of artificial life (ALife) are being or could be incorporated into virtual worlds. ALife has a unique and powerful role to play in the inhabited virtual world and its communities. The contribution of Alife in cyberspace can be divided into two parts:
  1. To provide biologically inspired behaviors, including animated behaviors, growth and decay, generation and mutation to draw users into these spaces.

  2. To power underlying archtiectures with biological metaphors.

Using Alife to draw attention span

We have seen the success of non networked CD-ROM games such as 'Creatures' from Cyberlife of Cambridge, UK, Petz from P.F. Magic of San Francisco and the ubiquitous Tomogatchi of Japan in capturing the human imagination, attention span and pocket book. Networked environments, such as gameplay systems, and social creative virtual worlds, are all on the verge of acquiring richer biological metaphors. For networked gaming, the drive for more lifelike animation, better combatant characters and more rich and changeable worlds inspires efforts such as Motion Factory’s Piccolo, a state machine based character animator. Players soon tire of key-framed repeatable behavior sequences and yearn for objects that seem to learn their moves through stimuli from the human players. Believable physics, non-canned motion, stimulus and response learning drive developers to borrow from biology.

Social creative virtual worlds have similar needs to gameplay systems, with less emphasis on real time low latency action. Moves to introduce biologically inspired experiences are already underway in these spaces. It is felt the introduction of Alife metaphors will not only draw in many more users but also strengthen the community matrix. Pets and gardens, perhaps our most intimate biological companions in the physical world, would serve to improve the quality of life in the virtual fold.

Alife powering better virtual world architectures

The recent failure of many efforts in the VRML community to promote an all encompassing standard which would serve behavior rich virtual worlds over the net points out the pressing need for better architectures. The key to delivery of better experiences to a variety of user platforms on low bandwidth connections is to understand that the visual representation of a world and its underlying coding need to be separated. This separation is a fundamental principle of living forms: the abstract coding, the DNA is vastly different than the resulting body. This phenotype/genotype separation also has another powerful property: compression. VRML simply defined a file format, a phenotype, which would be delivered to a variety of different end computers (akin to ecosystems) without any consideration of scaling, or adapting, to that end computer. A biologically inspired virtual world would more effectively package itself in some abstract representation, travel highly compressed along the thin tubes of the Internet, and then generate itself to a complexity appropriate to the compute space in which it finds itself.

As the virtual environment unfolds from its abstraction, it can generate useful controls, or lines of communication, which allow it to talk to the worlds back on servers or to peers on the network. These lines of control can also create new interfaces to the user, providing unique behaviors. One might imagine users plucking fruit from virtual vines only to have those vines grow new runners with fruit in different places. With non-generative, or totally phenotypic models, such interaction would be difficult if not impossible. As we will see in the description of Nerve Garden later in this paper, important scenegraph management techniques such as polygon reduction or level of detail and level of behavior scaling could also be accomplished by the introduction of ecosystem style metaphors. If we define the energy state of a virtual world inversely to the computing resources it is consuming, it would be more beneficial for any scenegraph or objects in it to evolve more efficient representations. 

Sherwood Forest Town: A Virtual Village on the Internet

Figure 4: Meeting in Sherwood Old Town
Click on this image to bring up the print resolution version

Sherwood Forest Community (figure 4) was one of the earliest experiment in virtual community building within a 3D world on the Internet. It was carred out between January of 1996 and late 1997 within the first 'constructivist' on-line 3D virtual world: AlphaWorld. AlphaWorld is the first virtual space to be hosted in the Active Worlds environment, now owned by Circle of Fire Studios. Sherwood Forest Town was a district set aside within AlphaWorld of about two hectares in size. The township was built and inhabited by members of the Contact Consortium, an organization dedicated to studying, promoting and enriching Internet-based virtual worlds as a new space for human contact and culture. Consortium members include individuals connecting to the Internet from home, specialists in industry, researchers from universities, and the staffs of companies and government institutions. Consortium members have years of experience in designing and running MUDs virtual communities used in coursework, in computer graphics, and world building exercises. These diverse backgrounds were applied to the Sherwood Forest Community Project.

The purpose of Sherwood was to design a very natural, attractive setting with woodlands, flowers and flowing water and then attract a community of users to build a village community in that space. A unique feature of Active Worlds is that it allows users all over the Internet with nothing more than a Windows PC and a modem connection to navigate and build in a large virtual space while interacting with others. Using this capability, Sherwood community planners recruited builders from some of the thousands of registered citizens of AlphaWorld. During and after the building of the town, informal observations would be taken and recorded and help the organization carry out more formal exercises later.

Why did we pick the theme of Sherwood Forest? Apart from the attractive fable of Robin Hood (which supplied some imaginative roles), it turns out that the Luddite movement against technology began in the Sherwood Forest region of Britain. We felt that if there was some provocative questioning of (or rebellion against) life in this new virtual worlds technology it might as well happen inside a virtual Sherwood Forest!

Town Charter: spinning the social matrix
Before starting on the building of the site, or the assigning of roles, we created a community charter. Every community needs some sort of charter or constitution or set of rules, whether formal or informal. Sherwood's charter was designed to support the following goal:

To create a viable community of interest within this new medium of human interaction and to observe how this community is built grows and functions.

The Spirit of our Community Underlying the Charter

(ye olde) Town Services Mandated by the Charter in the spirit of the theme of Sherwood
Some of the roles defined for and filled by participants included:
Sherwood Timeline

Figure 5: Sherwood citizen co-creator (psychotherapist Steve Lankton) builds Therapies ‘R’ Us
click on image to bring up print resolution version

From the initial town layout in January 1996 to completion of town construction in July of that year over sixty individuals participated in the project, ranging from 9 year old children to a professional architect and database designer. The following timeline should give you an idea of the phases and events which characterized this experiment:
What was learned
The Sherwood Forest Town community experiment was designed as an exercise in collaborative construction, group role playing, goal setting and achievement all in a shared 3D virtual world open to the general public accessible through dial up connections on personal computers. Sherwood was a success in so much as the town was designed, built and maintained for a period of time. The town is still online in fact (see Come Visit Sherwood below). Community roles shifted as the time commitments for Lady of the Land and building instructors were quite extensive. The combination of in-person gatherings with in-world meetings on the major event days was very valuable to keep the teams motivated. Documentation and study of the process, although not rigorous, did provide the framework for a large number of subsequent projects in the Active Worlds environment (we participated in: TheU Virtual University, Arslab, University of California Virtual High School, and the UC Santa Cruz V-Tour amongst others).
Come Visit Sherwood
Find the home of Sherwood Forest Town on the Contact Consortium Homepage at: Visit the Sherwood Forest Community on the Internet by downloading and installing the Active Worlds Browser, entering AlphaWorld, and then teleporting to the coordinates: 105.4N 188.8E (turn around after you land to see the main gate). Note that you can also set up your web browser to teleport directly into various parts of Sherwood by clicking on teleports found throughout the Sherwood Forest Town Web pages.
TheU Virtual University Architecture Competition
TheU Virtual University (figure 6) started life as an idea born at a University of Toronto Marshall MCluhan workshop held in the Fortezza da Basso in Florence in May of 1996. A team of people comprising computer professionals and students brainstormed the idea for a virtual university inside a 3D on-line world and created a prototype in AlphaWorld for a presentation at the end of the workshop.

Figure 6: San Francisco State University students meeting in TheU University Development Center
Click on this image to bring up the print resolution version

Birth of an experimental pedagogical virtual world: TheU

Shortly after this workshop, a dedicated Active World server, TheU, was donated to the Contact Consortium for special experimentation. The goal of TheU is to serve as a test bed straddling between traditional campus based universities and the growing number of distance learning projects. Distance learning using current methodology offers many advantages to students in remote areas and students attending part-time courses. However it lacks the sense of community and social interaction which can be achieved by sharing the same environmental spaces and experiences. In the long term Virtual Worlds technology may become a tool for enabling completely new and innovative teaching methods.

We felt we could draw from earlier textual networked learning communities, including SolSys Sim from Northern Arizona University (see it on the web at, Diversity University, College Town, VOU (Virtual OnLine UNiversity), to name just a few. TheU would seek to go beyond these experiments due to its unique combination of social interaction, visual human embodiment and user definable virtual environments. Playing it safe for our first experiment, we opted to stay with familiar metaphors of a university campus with its instructional spaces, tutorial help centers, social commons, and library reference zones. Utilizing the power of the Active Worlds builder community, we decided to host a virtual architecture competition to generate a range of approaches to using a virtual world in pedagogy. Fortunately for the organization, Stuart Gold, a British architect and database expert with a long background in online systems, took the lead in this effort, operating the event as a professional juried competition. For your reference, please visit TheU Virtual University and see the results of the Architecture Competition at
Competition to Build the First Phase - Institute of Virtual Education
It seemed appropriate that the first faculty of TheU should concern itself with the study and application of Virtual Worlds technology to the field of education. Consequently, the first phase of the university is to be the Institute of Virtual Education. It is hoped that in the early days of applying this new technology, the Institute will attract people from all over the world to debate and take part in the future development of the University and of Virtual Education in general. The Institute’s role will be to:
Aims and Objectives of the Competition
Since the inception of Alpha World, its citizens have produced many stunning and innovative virtual spaces and structures. It therefore seemed appropriate to ask Alpha World citizens to take part in a competition, hosted and sponsored by SRT Enterprises and the Contact Consortium, to design the Institute of Virtual Education. The goal of the participants was to create a virtual environment which could best meet the following criteria on which it would be judged: Participants were given a large degree of freedom in their interpretation of the requirements. As the driving technology is so fluid and is constantly evolving we felt that the participants should evolve their ideas over the period of the competition and have access to a consultative panel of experts, who would also be the judges, via a listserv available to all the entrants. The panel was made up of educators, architects, artists/designers and technologists including: Murray Turoff from the New Jersey Institute of Technology, Marcos Novak from UCLA, Derrick Woodham from the University of Cincinnati, Gerhard Schmitt from the ETH in Zurich, John Tiffin of Florida State, two of the authors of this paper, and others.
Competition Procedures and Prizes
There were 34 teams, each of whom were given an Active Worlds personal server which was donated by Circle of Fire and hosted by SRT Enterprises. Each of the servers were configured to allow any Active World user to enter and only one participant (or a team using privileged passwords) to build in the world. The duration of the competition was around six weeks.

Due to the open-ended nature of the requirements and the emphasis on ideology and innovation, the participants were encouraged to develop one or more web pages, linked to their schemes, which served to describe their designs and the concepts behind them. Participants were encouraged to outline how their designs related to the learning and educational process and how, if at all, they incorporated or could be extended to take account of, future changes in the technology.

Figure 7: Competition participants, judges and bystanders meet in the pavilion
Click on this image to bring up the print resolution version

A competition pavilion was constructed in TheU (figure 7) which acted as a communal area for all the participants, and contained teleports for Active World users and competition judges to enter each of the worlds.
The Competition
After six weeks of intense building in all 34 competition worlds, six entries were short listed for serious consideration. On March 20, 1998, the final walk through of the finalist worlds with their builders, the judges and a large group (40 to 50) of observers occurred. This event lasted almost four hours. With any in-world event, careful planning must occur to keep it from degenerating into chaos. The following steps were taken to make this coherent, and obtain value for the participants:
  1. The event had a clear structure, advertised from the beginning: meeting in the Pavilion, a tour of the six finalist worlds, with the judges, narrated by the builders of the worlds. Strict control of the pacing, moving on between each world every 20 minutes. A final gathering at the pavilion, voting and announcement of the winners by placing banners in the pavilion for all to see.

  2. Assignment of gatekeepers and guides: we had trained world users at the pavilion to guide newcomers and folks who crashed their software, back into the live tour. They used private telegram to stay in constant contact with the event leaders.

  3. A pair of event leaders, in charge of herding of attendees, crowd control, discipline of event crashers, communications with gatekeepers and generally keeping the conversation interesting and on track.

  4. Documentarians were logging all text chat and taking a continuous series of screen shots of the walk through, which can all be seen at

  5. Voting of judges was by secret ballot, sent by telegram and email with followup after the event.

What was learned
As TheU competition was seen as a following in the footsteps of the original Sherwood Town experiment, we felt we had achieved some major goals including: greater consistency of the event, including clear, published goals, well defined roles and concrete outputs: the winning worlds and their documentation. Did we construct a viable Institute of Virtual Education? Apart from the great aesthetic value of the winning world, Aurac, and its merit for use in demonstrations, it did not serve our needs for the Institute.

To take these experiments to the next generation, Bonnie DeVarco lead a team in the construction of a 'virtual high school' (VHS) under the umbrella of the University of California at Santa Cruz VHS initiative. This site is hosted in TheU and was initiated with design input by DigitalSpace Corporation (Bruce Damer and Stuart Gold participating). The VHS was built by Craig and Penny Twining of Active Arts Design. Bonnie DeVarco also worked tirelessly to obtain the permission for the display of works of numerous authors made accessible on the walls of the various wings of the VHS. This space contained a great deal of images, links, objects and audio narration in virtual classroom and tutorial areas focused on science, language and geometry. You can learn more about the VHS at

The richness of both TheU competition and VHS environments yielded their own problems: overbuilding created slow frame rate performance and the danger of a 'museum effect', in that the environments became static demonstration areas only. Three valuable principles emerging from this experience were:
  1. Do not make your virtual worlds too large. Large spaces can cause users to get lost and provide a scarcity of immediate stimulating objects and other affordances to draw them on to the next activity.

  2. Do not design worlds that seek to model real world places, unless those places are particularly suited to support interaction in a virtual environment. Navigation and habitation of virtual spaces is so different than the same activities in a physical setting, that a great deal of wasted objects and real estate can result if one is trying to be faithful to the real world setting. Potemkin villages, theme parks, town squares or shopping malls, designed for denser crowding with plenty to see and do are some of the very few real world models worth emulating in virtual space.

  3. Design worlds that are constantly changing and changeable. In fact, the 'ground zero' (default entry area) of TheU has become a major meeting area, filled with the changing detritus of signage, teleports and weblinks from prior events while the 'museum areas' are static and preserved only for narrative tours.

Come Visit TheU
Find TheU Virtual University on the Contact Consortium Homepage at: TheU is a frequently used, changing world that will continue to evolve. Visit TheU on the Internet by downloading and installing the Active Worlds Browser, entering AlphaWorld, and then selecting TheU from the listing of worlds on the left hand side of the interface.
Biota’s Nerve Garden: a Public Terrarium in Cyberspace
Nerve Garden is the Consortium’s first major attempt to marry Artificial Life metaphors with virtual worlds. The projects described earlier in this chapter were attempts to build a strong social context and achieve something meaningful inside a 3D inhabited space. The Nerve Garden was designed to bring a multi-user biologically inspired space online and eventually marry it with avatar embodied social environments. This is a work in process and we invite your participation.

History of the project

During the summer of 1994, one of us (Damer) paid a visit to the Santa Fe Institute for discussions with Chris Langton and his student team working on the Swarm project. Two fortuitous things were happening during that visit, SFI was installing the first Mosaic Web browsers, and digital movies of Karl Sims’ evolving 'block creatures' (Sims, 1994) were being viewed through the Web by amazed students (figure 8 and on the Internet at It was postulated then that the combination of the emerging backbone of the Internet, a distributed simulation environment like Swarm and the compelling 3D visuals and underlying techniques of Sims’ creatures could be combined to produce something very compelling: on-line virtual worlds in which thousands of users could collaboratively experiment with biological paradigms.

Figure 8: View of Karl Sims’ original evolving block creatures in competition
Click on this image to bring up the print resolution version
One of the Contact Consortium’s special interest groups, called, was chartered in mid 1996 to develop virtual worlds using techniques from the Artificial Life (ALife) field. Its first effort is Nerve Garden, which came on-line in August of 1997 at the SIGGRAPH 97 conference. Three hundred visitors to the Nerve Garden installation used L-systems and Java to germinate plants models into a shared VRML (Virtual Reality Modeling Language) world hosted on the Internet. is now developing a subsequent version of Nerve Garden, which will embody more biological paradigms, and, we hope, create an environment capable of supporting education, research, and cross-pollination between traditional A-Life subject areas and other fields.

Nerve Garden I: architecture and experience

Figure 9: Flight of the bumblebee above Nerve Garden
Click on this image to bring up the print resolution version
Nerve Garden I (figure 9) is a biologically-inspired shared state 3D virtual world available to a wide audience through standard Internet protocols running on all major hardware platforms. Nerve Garden was inspired by the original work on ALife by Chris Langton (Langton 1992), the digital ecosystem called Tierra by Tom Ray (Ray 1994a) and the evolving 3D virtual creatures of Karl Sims (Sims 1994). Nerve Garden sources its models from the work on L-systems by Aristide Lindenmayer, Przemyslaw Prusinkiewicz and Radomir Mech ( Prusinkiewicz and Lindenmayer 1992) (Mech and Prusinkiewicz, 1996).

The first version of the system, Nerve Garden I, allowed users to operate a Java client, the Germinator (figure 10) to extrude 3D plant models generated from L-systems. The 3D interface in the Java client provided an immediate 3D experience of various L-system plant and arthropod forms. Users employed a slider bar to extrude the models in real time and a mutator to randomize production rules in the L-systems and generate variants on the plant models. After germinating several plants, the user would select one, name it and submit it into to a common VRML97 scenegraph called the Seeder Garden.

Figure 10: Lace Germinator Java client interface
Click on this image to bring up the print resolution version
The object passed to the Seeder Garden contained the VRML export from the Germinator, the plant name and other data. Another Java application, called NerveServer, received this object and determined a free 'plot' on an island model in a VRML scenegraph. Each island had a set number of plots and showed the user where his or her plant was assigned by a red sphere operated through the VRML external authoring interface (EAI). Cybergardeners would open the Seeder Garden window where they would then move the indicator sphere with their plant attached and place it into the scene.

Various scenegraph viewpoints were available to users, including a moving viewpoint on the back of an animated model of a flying insect endlessly touring the island. Users would often spot their plant as the bee or butterfly made a close approach over the island. Over 10MB of sound, some of it also generated algorithmically, emanated from different objects on the island added to the immersion of the experience. For added effect, L-system based fractal VRML lightening (with generated thunder) occasionally streaked across the sky above the Seeder Garden islands.

NerveServer permitted multiple users to update and view the same island. In addition, users could navigate the same space using standard VRML plug-ins to Web browsers on SGI workstations, PCs or Macintosh computers from various parts of the Internet. One problem was that the distributed L-system clients could easily generate scenes with several hundred thousand polygons, rendering them impossible to visit. We used 3D hardware acceleration, including an SGI Onyx II Infinite Reality system and a PC running a 3D Labs Permedia video acceleration card to permit a more complex environment to be experienced by users. In 1999 and beyond, a whole new generation of 3D chip sets on 32 and 64 bit platforms will enable highly complex 3D interactive environments. There is an interesting parallel here to Ray’s work on Tierra, where the energy of the system was proportional to the power of the CPU serving the virtual machine inhabited by Tierran organisms. In many Artificial Life systems, it is not important to have a compelling 3D interface. The benefits to providing one for Nerve Garden are that it encouraged participation and experimentation from a wide group of users. The experience of Nerve Garden I is fully documented on the Web at (see references below). Several gardens generated during the SIGGRAPH 97 installation can be visited.
What was learned
As a complex set of parts including a Java client, simple object distribution system, a multi-user server, a rudimentary database and a shared, persistent VRML scenegraph, Nerve Garden functioned well under the pressures of a diverse range of users on multiple hardware platforms. Users were able to use the Germinator applet without our assistance to generate fairly complex, unique, and aesthetically pleasing models. Users were all familiar with the metaphor of gardens and many were eager to 'visit their plant' again from their home computers. Placing their plants in the VRML Seeder Gardens was more challenging due to the difficulty of navigating in 3D using VRML browsers. Younger users tended to be much more adept at using the 3D environment.

In examination of its deficiencies, while it was a successful user experience of a generative environment, Nerve Garden I lacked the sophistication of a 'true ALife system' like Tierra (Ray 1994a) in that plant model objects did not reproduce or communicate between virtual machines containing other gardens. In addition, unlike an adaptive L-system space such as the one described in (Mech and Prusinkiewicz, 1996), the plant models did not interact with their neighbors or the environment. Lastly, there was no concept of autonomous, self replicating objects within the environment. Nerve Garden II, now under development, will address some of these shortcomings, and, we hope, contribute a powerful tool for education and research in the ALife community.

In conclusion, did Nerve Garden serve some of the goals for virtual worlds and Alife enunciated at the beginning of this chapter? The environment did provide a compelling space to draw attention while also proving that an abstraction of a world, that of an L-system, could be transmitted then generated on the client computer, achieving great compression and efficiency. When combined with streaming and ecosystem controls, Nerve Garden could evolve into a powerful virtual world architecture testbed (see The next steps: Nerve Garden II below).
Visiting Nerve Garden I
Nerve Garden I can be visited using a suitable VRML97 compatible browser. Models made at SIGGRAPH 97 can be viewed at The Biota project and its annual conferences are covered at

The next steps: Nerve Garden II
The goals for Nerve Garden II are:
  • to develop a simple functioning ecosystem within the VRML scenegraph to control polygon growth and evolve elements of the world through time as partially described in (Mech and Prusinkiewicz, 1996);

  • to integrate with a stronger database to permit garden cloning and inter-garden communication permitting cross pollination between islands;

  • to integrate a cellular automata engine which will support autonomous growth and replication of plant models and introduce a class of virtual herbivores ('polyvores') which prey on the plants’ polygonal energy stores;

  • to stream world geometry through the transmission of generative algorithms (such as the L-systems) rather than geometry, achieving great compression, efficient use of bandwidth and control of polygon explosion and scene evolution on the client side;

Much of the above depends on the availability of a comprehensive scenegraph and behavior control mechanism. In development over the past two years, Nerves is a simple but high performance general purpose cellular automata engine written as both a C++ and Java kernel. Nerves is modeled on the biological processes seen in animal nervous systems, and plant and animal circulatory systems, which all could be reduced to token passing and storage mechanisms. Nerves and its associated language, NerveScript, allows users to define a large number of arbitrary pathways and collection pools supporting flows of arbitrary tokens, token storage, token correlation, and filtering. Nerves borrows many concepts from neural networks and directed graphs used in concert with genetic and generative algorithms as reported by Ray, Sims (Ray 1994b, Sims 1994) and others.

Nerves components will underlie the Seeder Gardens providing functions analogous to a drip irrigation system, defining a finite and therefore regulatory resource from which the plant models must draw for continued growth. In addition, Nerves control paths will be generated as L-system models extrude, providing wiring paths connected to the geometry and proximity sensors in the model. This will permit interaction with the plant models. When pruning of plant geometry occurs or growth stimulus becomes scarce, the transformation of the plant models can be triggered. One step beyond this will be the introduction of autonomous entities into the gardens, which we term 'polyvores', that will seek to convert the 'energy' represented by the polygons in the plant models, into reproductive capacity. Polyvores will provide another source of regulation in this simple ecosystem. Gardens will maintain their interactive capacity, allowing users to enter, germinate plants, introduce polyvores, and prune plants or cull polyvores. Gardens will also run as automatous systems, maintaining polygon complexity within boundaries that allow users to enter the environment.


DEF spinalCordSeg Bundle {
Code Sample 1: Sample NerveScript coding language

We expect to use Nerves to tie much of the above processes together. Like VRML, Nerves is described by a set of public domain APIs and a published language, NerveScript. Figure 6 lists some typical NerveScript statements which describe a two chain neural pathway that might be used as a spinal chord of a simple swimming fish. DEF defines a reusable object spinalCordSeg consisting of input paths spinalTapA and spinalTapB which will only pass the token Swim into a four stage filter called bodyMotion. All generated tokens end up in Complex, another Nerve bundle, defined elsewhere.

Figure 11: Nerves visualizer running within the NerveScript development environment

Figure 11 shows the visualization of the running NerveScript code in the NerveScript development environment. In the VRML setting, pathways spinalTapA and B are fed by eventOut messages drawn out of the scenegraph while the Nerve bundles generate eventIns back to VRML using the EAI. Nerves is fully described at the web address referenced at the end of this paper.
In addition to the extensive contributions made by the authors of this paper, we would like to thank the following sponsors: Intervista, Silicon Graphics and Cosmo Software, 3D Labs. A special thanks goes to Przemyslaw Prusinkiewicz and numerous other individuals who have worked on aspects of the project since 1995.

IV. The Long View: Virtual Worlds as a Primordial Soup for Society, Technology and Life on Earth

The Future of the Medium
Virtual Worlds are a medium in search of an application. At a July 1998 Avatar conference in Banff, Alberta, Canada, a consensus emerged that it was too early in the medium to know how it would ultimately be used. It was felt that it was good that a 'killer app' had not been identified and that avatar cyberspace had time to continue to evolve for its own sake and not to serve possibly inappropriate applications. Comparisons were made to the birth of important technological media of the past century. The telephone was first thought of as a way to distribute music, early film was first cast as a facsimile of theater, and the radio was considered as a method for the delivery of lectures and person to person two way communication between communities.

It is clear from the recent falling off of investment in commercial virtual world platforms, that the medium is entering its 'winter', supported only by die-hard users and smaller efforts, largely to build home-brewed virtual worlds and virtual spaces from university and research communities. Millions of computer users have been only recently acclimatized to using classic windows and icons desktop metaphors. Those users are now comfortable in dealing in a cyberspace made up of lists of text, and documents in the form of the Web. Another generation, brought up on Doom, Quake, Nintendo 64 and other environments that stress navigation through very complex, 3D spaces full of behaviors, may be more apt to demand a cyberspace that is built around the metaphor of a place, not just an interface. Will that generation bring us more into virtual worlds for play, learning, work and just being? What will cyberspace look like in ten years, like Gibson’s Matrix or Stevenson’s Metaverse (Gibson 1984, Stephenson 1992) or will the document based web and streaming video and audio spaces be the dominant paradigm?
Prospects for a Cambrian Explosion Inside Cyberspace
At the first annual conference of, held in the summer of 1997 at the site of the Burgess Shale in Canada, an important source of fossil evidence of the creatures of the 'Cambrian explosion' of life 535 million years ago, Tom Ray asked the question: 'what are the conditions for the creation of a Cambrian explosion in cyberspace?'. Let us finish this chapter with a journey into the farthest realms of speculation. Let us reverse the question and ask 'why is life trying to create the conditions for a Cambrian explosion in DigitalSpace?'. We strive to introduce our concepts of 'artificial' life to a new medium, virtual worlds. If in these spaces we witness the basic metaphors of biological systems, regardless of whether they are expressed as atoms or bits, we may be creating truly new forms of life. Or we may be a surrogate for selfish genes to find their way into a very remarkable new ecosystem with some very special properties. The speculative piece below was derived from a speech given by one of us (Damer) at the second annual Biota conference held at Magdalene College, Cambridge UK in the Summer of 1998. This conference is described at
Simulacara to Nanocara, or why is life trying to Enter DigitalSpace?
Kevin Kelly writes in 'Out of Control' in reference to the Gaia theory that '..summer thunderstorms may be life raining on itself'. He also declares that '..the realm of the born.. and the realm of the made.. are becoming one. Machines are becoming biological and the biological is becoming engineered' (Kelly 1994).

Seen from another perspective, alien visitors gazing down on our world from high above would almost certainly declare hominid cities, redwood forests, roadways, termite complexes, power grids, coral reefs and other macro structures as all very interesting growths of the biosystem.

Indeed, the grid-patterned, store and forward, clock-pulsed nature of our city streets would be seen by these aliens mirrored in the design of computer circuitry. And yes, every time I fly over Silicon Valley it looks more and more like an Intel Pentium Processor! In addition, at a deeper level, the aliens would note similarities between the molecular token flow machinery of the cell and the message traffic and control linkage of computer operating systems and networks.

There is strong evidence that stromatolites and other ancient cousins transformed the oceans and atmosphere, adding free oxygen and shaping the geology of continents. Nature has once again contrived a powerful biological catalyst agent and is again raining change on itself. But where is Nature headed this time?

Breaching Barriers
If life first developed around deep hydrothermal vents it must have managed to travel through the blackness from extincting smokers to new sources.

The Stomatolites and their ilk opened a much more energetic biotic highway for those cells fortunate enough to metabolize oxygen, the new pollutant of the day. Steven Rooke will talk later about this Oxygen holocaust and Margulis’ symbiogenesis. This highway carried life through the water-air-land barriers to our own time.

Barrier breaching required the constant engineering and co-opting of new supporting machinery. Margulis’ eukaryotic symbiots absorbed simpler bacteria along the way up the oxygen and solar energy highways.

Then came the hominid brain and its teams of memes driving these ten digits to write yet more supporting structures for the next journey. Cyberspace began as a mesh for memes but where memes tread can genes be far behind? Will the meme, carefully encoded in its new digital bilipid casement, create a new eukaryotic cell by absorbing the more automatous digital biote?

In a brief 20th century lineage of digital biota we have seen the coming of simple computer viruses, digital creatures as pet things, and larger virtual ecosystems like Tierra, hovering around the few rich cyberthermal bitstreams and feeding centers of human attention.

Will we see in the next century a new life cycle: meme gestation, happening for a time in human minds, meme-gene colonization, replication and mutation in cyberspace, light speed travel, and time stasis in dormant storage, and a chrysalis to moth stage spun into atoms and out into the universe by molecular nanofabrication?

But Why is Life Trying to Enter DigitalSpace?
Can selfish genes in a sort of collective angst be aware that the clock will ultimately run down? Individuals are programmed to die but do not genes strive to continue for ever? Perhaps these genes created consciousness to contemplate life’s origins and its ends. Through us, our genes can now know about their ultimate end. The inevitable end will happen in a distant eon as our red giant sun, starved of hydrogen, consumes all genes and memes still dwelling down in this gravity well. Other ends could be more imminent, including untimely impacts or the impact of the prodigious human CO2 emitter. There is evidence is mounting that the Permian extinction (much more deadly than the more famous Jurassic event) was a near miss with a total greenhouse effect. And perhaps not an absolute extinction but a setback of a billion years of machinery and atmosphere building is as good as a termination condition.

So will life enter DigitalSpace in search of an ultimate persistence? What advantages are there to be gained by evolving to live in such an ephemeral, narrow and arid ecosystem? One advantage is super charged selection, freed from the slow speed of chemical replication and limited supply lines of atoms, the essential genetic machinery can be copied relentlessly rapidly. Of course, the machinery of the ecosystem itself is still atomic and at this point extended relatively slowly by we the memetic partner. When the atomic support system is also spun by the genes of the digital biotes, the pace will pick up dramatically.

One other distinct advantage of digital biota is lightspeed travel. Massless organisms can escape gravity’s well easily, and traverse the solar system in mere hours. If Freeman Dyson is right the collective surface of the Oort cloud, Kuiper belt and various comets and asteroids may be the largest and most fertile surface for ex-terrestrial life.

20th Century emissaries to this zone include spacecraft such as Galileo, whose software brain is constantly morphed and improved by the meme partners at JPL. Clearly humans are poorly adapted to a hard vacuum. Preceding us into these realms will need be countless infrastructure builders better suited for life there.

So will we live to see sometime in the next millenium, biologic nano fabricated asteriodal lichens in symbiotic spore spreading colonies in the outer solar system instanced out of cyberspace?

And at least some of Earth’s biological eggs will be out of the proverbial single basket. This would be a wonderful legacy that humankind could leave from its glorious and destructive time in the biosphere.

Rheingold, Howard, 1993, The Virtual Community: Homesteading on the Electronic Frontier, New York NY: HarperPerennial.

Benedikt, Michael, ed. 1991, Cyberspace: First Steps. Cambridge: MIT Press.

Damer, B., Kekenes, C, Hoffman, T., 1995, Inhabited DigitalSpaces, published in ACM CHI '96 Companion, page 9.

Damer, B., Inhabited Virtual Worlds, ACM interactions, sept-oct 1996, page 27.

Damer, B., 1998, Avatars, Exploring and Building Virtual Worlds on the Internet, Berkeley: Peachpit Press.

Powers, Michael, 1997, How to Program Virtual Communities, Attract New Web Visitors and Get Them to Stay, New York: Ziff-Davis Press.

Wilcox, Sue, 1998, Creating 3D Avatars, New York: Wiley.

Turkle, Sherry, 1995, Life on the Screen: Identity in the Age of the Internet, New York: Simon and Schuster.

Sims, K., "Evolving Virtual Creatures," Computer Graphics (Siggraph '94) Annual Conference Proceedings, July 1994, pp.43-50.

Ray, T. S. 1994a. Netlife - Creating a jungle on the Internet: Nonlocated online digital territories, incorporations and the matrix. Knowbotic Research 3/94.

Ray, T. S. 1994b. Neural Networks, Genetic Algorithms and Artificial Life: Adaptive Computation. In Proceedings of the 1994 ALife, Genetic Algorithm and Neural Networks Seminar, 1-14. Institute of Systems, Control and Information Engineers.

Langton, C. 1992. Life at the Edge of Chaos. Artificial Life II 41-91. Redwood City CA: Addison-Wesley.

Prusinkiewicz, P., and Lindenmayer, A., eds. 1990. The Algorithmic Beauty of Plants. New York: Springer Verlag.

Mech, R., and Prusinkiewicz, P. 1994. Visual Models of Plants Interacting with Their Environment. In Proceedings of SIGGRAPH 96 . In Computer Graphics Proceedings, 397-410. ACM Publications.

Gibson, William, 1984, Neuromancer New York NY: Ace Books.

Stephenson, Neal, 1992, Snow Crash New York NY: Bantam Spectra.

Kelly, Kevin, 1994, Out of Control: The New Biology of Machines, Social Systems and the Economic World, Perseus Press.
Please send any comments on this chapter to Bruce Damer

Return to DigitalSpace Documents