Shift-Life Alternate Biology and Mixed Reality


Artificial Life Programmer: Eugene Ch'ng | Environmental Sensor Networks: Sarah Mount
Graphic Artworks & Animation Sequence: Samantha Moore | Lead Artist & Project Leader: Dew Harrison

Acknowledgements

The Shift-Life project, supported by the Arts Council England, The Shrewsbury Museums Service and Shift-Time Festival Organisers is originally developed to engage public interaction. The project was shown at the Shift-Time Festival of Ideas at Shrewsbury (Darwin's birthplace) from 3-12 July 2009. The installment is now housed at the Wolverhampton Art Gallery and was demonstrated at the Gadget Show at NEC Birmingham (4-11 April 2010) [video].

In order to interact with the virtual ‘sweet’ bugs they are projected down into a real box arrayed with sensors. This takes the form of a wooden 1.2 meter sq box filled with polystyrene beads held under a muslin sheet and surrounded by a set of manipulative tools which, when activated, can affect in real-time the projected virtual world of creatures causing them to adapt to survive in their rapidly changing ecosystem. The tools are for hammering earthquakes into existence, watering to alter the humidity and pH count of the planet environment and altering light sources to affect temperature and depth of shade.

 

General Creature Behaviour
The system is constructed with a trophic network of predator-prey and vegetation. The organisms are short-lived (60 seconds minimum and 150 seconds maximum). The general behaviour of each organism is its survivability and the reproduction of progenies. The survival of the entire ecosystem depends on the balance of the organisms that inhabit the landscape. If the predator out-grows the prey, an imbalance occurs and the system perishes. If the prey out-grows the edible plants, the food is scarce and the system is at a dilemma. If the canopies (large trees) over-reproduce, the predator has little space left to hunt. If the red poison plants outgrow the vegetation, more herbivores eat them and become toxic; consequently their newly acquired toxicity kills the carnivores. (See Figure 3.) When the environment particularly suits them, a plant species will thrive (poison plants love high pH levels). The difficulty of such an alife development is the maintenance of equilibrium. The ‘fun’ part is when users interact with the system by increasing any of the environmental factors via our sensor network: temperature, sunlight, humidity, pH level. They can do this by using watering cans, hammers, and lamps.

Rules of Life
We approached the development task with an agent-based modelling technique. That is, we modelled each individual unit of biological life as an autonomous agent. Simple rules (computer algorithms) were built into each entity. The ecosystem has two vagile organisms (carnivore and herbivore) and three sessile organisms (poison plant, vegetable, and tree). The rules for each organism are specified below.

Carnivore

  • Sense the environmental (Temperature, Sunlight, Humidity, earthquake)
  • Grow (aging) and die of senescence
  • Roam when not hungry
  • Avoid tree canopies
  • Look for herbivore when hungry
  • Hunt when herbivore in sight
  • Rest when tired
  • Hide when in danger (earthquakes)
  • Reproduce when sexual maturity is reached
  • Die when the fitness is depleted

Herbivore

  • Sense the environmental (Temperature, Sunlight, Humidity, earthquake)
  • Grow (aging) and die of senescence
  • Roam when not hungry
  • Look for edible plants when hungry
  • Move to eat plant when in sight
  • Change colour when toxic plant eaten
  • Rest when tired
  • Flee when in danger (being hunted)
  • Reproduce when sexual maturity is reached
  • Die when the fitness is depleted

Vegetation (in general)

  • Sense the environment (Temperature, Sunlight, Soil, Humidity, pH level, Space)
  • Grow (aging) and die of senescence
  • Compete with nearby plants for space
  • Reproduce when sexual maturity is reached
  • Die when the fitness is depleted

Creature Adaptability and Environmental Factors

The fitness of each organism is measured by Ch’ng’s Adaptability Measure [3]. The creatures are affected by three environmental factors: temperature, sunlight and humidity and the plants are affected by six factors: temperature, sunlight, soil, humidity, pH level, and space. The temperature, sunlight, humidity and pH level are streamed from electronic sensors installed at strategic locations in the virtual bug box. Soil conditions are unchanged and are based on height fields (certain regions are more habitable). The availability of space for the plants depends on the number of plants growing within that space.

Publication: D. Harrison, E. Ch'ng, S. Mount, and S. Moore (2009) Experiencing the Big Idea: Shift-Life Mixed Reality Interface, 8th International Conference on Digital Arts and Culture, DAC'09 12-15 December 2009, Irvine, California, USA.