TCD researchers are building a 3D virtual replica of Dublin, writes Karlin Lillington.

James Joyce famously bragged that if Dublin were destroyed, he could recreate it from memory. But 21st century writers have it easier - they could recreate it from Virtual Dublin, a 3D replica of the city being built by a team of researchers at Trinity College Dublin in a multimillion euro project called Project Metropolis.

Already, a visitor to the immersive computer-generated world can walk through the big wooden doors at Front Gate of the university, admire the stonework entryway, cross a virtual Front Square filled with strolling pedestrians, pop out one of the side gates, head over to Temple Bar and window shop.

The visitor can alternatively pan upwards for an aerial view in which - thanks to the use of aerial photography and a hired helicopter - many rooftops are duplicated in precise detail, the carvings on the top of the Custom House can be appreciated from a unique angle, and an amazingly realistic Dart train can be seen stalled on Butt Bridge.

"This is much more realistic than [online virtual world] Second Life," says Prof Carol O'Sullivan of Trinity's computer science department, one of the Project Metropolis team, "and it's a good framework for doing studies into human perception."

Many shop fronts and buildings are reproduced in careful detail and, instead of the blocky people in skin-tight clothing found in Second Life, Virtual Dublin's inhabitants walk like humans, wear a variety of clothes in different patterns, and the fabric of loose trousers, or a tight skirt, moves as the "person's" legs move beneath them.

The high degree of reality is not simply an exercise in virtuoso animation, however; it is an important part of a €2.5 million Science Foundation Ireland (SFI)-funded project that should have commercial application in the computer gaming and urban planning sectors, and also in healthcare.

The project has been ongoing for five years, during which time it has produced three Ph.Ds and generated many respected papers given at international conferences. By the end of this year, 20 people will be actively involved in the research work.

A wide range of partners are involved, from the TCD researchers to computer and gaming companies such as IBM, Sony Computer Entertainment, Creative Labs, Demonware, Havok, OC3 Entertainment - and the Environmental Protection Agency.

The last-mentioned is interested in how a virtual world might enable full simulations of planning projects - which has made the project of interest to Dublin City Council as well.

O'Sullivan says people could view a simulation of a planned development or road system, for example, and actually hear the level of noise a road would generate, see the increased number of pedestrians and traffic and see how new buildings would affect the cityscape.

Under new EU guidelines, planners will have to make simulations available to citizens and a computer simulation has the potential to be far more realistic a representation than a chart of a sound map of estimated road noise, she says. "You could actually take something around on a laptop for citizens in an area to view."

The gaming industry has an obvious interest in such a project as well. With computer games generating more revenue than the entire Hollywood film industry these days, increased realism and finely tuned immersive environments are extremely important to games. Hence the involvement of some of the gaming industry's big names in Project Metropolis.

"Even though the primary application may be games, these kinds of virtual environments are going to be more ubiquitous," says O'Sullivan. "This will be a new form of communication for people."

That's not science fiction, either. Already, millions of people spend hours every week living an alternative virtual life in the online world called Second Life.

Sony is planning an extension of its new internet-enabled PlayStation3 gaming station that will allow owners to enter a virtual world, meet friends and family in the form of avatars to share their online music and pictures, chat - even buy furniture for their virtual apartment, and virtual clothes for their avatars.

But Project Metropolis is expected to have some more profound uses, too.

"This will improve our understanding of the human brain," says Dr Fiona Newell, a TCD cognitive neuroscientist involved with the project.

"A world like this could be used to rehabilitate people who are socially disabled - who are agoraphobic, perhaps, or autistic - because all the variables can be controlled. You could also safely put people into otherwise dangerous situations."

A joint project with the Central Remedial Clinic is already on the cards that will allow children at the clinic to drive vehicles and explore Virtual Dublin.

There's plenty more to do: the streets are eerily sans traffic at present and, if you look carefully at the thousands of strolling people, you'll notice they are all based on four different models wearing a limited range of clothing.

The researchers are also busy recording Dublin sounds so that the world will have a full auditory component.

The researchers also hope to get some video clips up on Trinity's website before too long, so people can see Virtual Dublin for themselves.

But the project already has had some immediate payback for at least one of the team.

Says O'Sullivan: "My kids are finally interested in what I am doing."

Project Metropolis: what is it?

• Also called Virtual Dublin, it is a multimillion-euro project based at Trinity College that recreates Dublin as a 3D virtual world.

• More than 2sq km of Dublin city are currently represented to a high level of detail, and the model will encompass 5sq km.

• More than 50,000 virtual people are wandering around its streets.

• Up to a week's work is required to produce a single building.

• Five years' work has gone into Virtual Dublin already.

• Computer scientists, animators and a neuroscientist are involved in its creation.

• Researchers have received €2.5 million from Science Foundation Ireland (SFI) to further develop it over the next four years.

• The grant is the largest given by SFI for a computer graphics/simulation project.

• Researchers expect it to have commercial applications in the gaming and public planning areas, and in healthcare applications.