We've all seen artists' views of a new development. But who creates them, and how? By Caitlin Davies

The 2012 Olympics might still be six years away but, in London at least, there has already been a boom in demand for architectural visualisers. And if you don't know what an architectural visualiser is, you're not alone. "It's the best job you've never heard of," says Nik van Herpt, who has 15 years experience in the field.

Architectural visualisers work with architects, taking blueprints for designs and then creating visuals - otherwise known as artists' impressions. In the past this meant watercolour or pen-and-ink drawings. Today it's more likely to be "photo-real" images using computer design programmes.

The benefit of the digital approach, says van Herpt, is that you can revolve the image, see it from all angles, and "spot the areas that have been missed." It was van Herpt who created some of the visuals for the Olympics before London won the bid - the animations on TV news reports that appeared to "grow" towards the screen. He has since formed his own visualisation company, Ironcoast, and says the Olympics is definitely creating job opportunities.

Today most architectural projects involve some sort of visualisation, in order to iron out design issues in the development stage, to get planning permission, and to use in marketing. Many big architectural firms have in-house visualisers, but there are also studios that work independently. A junior visualiser starting out on their career will earn around £17,000, but, once they are managing projects, the pay gets nearer £30,000.

For Iain Denby, who has been an architectural visualiser for 18 years, a normal job goes like this: a developer buys some land on which to build an office block, they then ask an architect to design the building, and the architect hires a visualiser. Denby also gets commissions from the developer direct, or from a marketing agency. A typical job takes him five days, during which he builds a 3D model on a computer. The computer then renders a fixed image from a particular viewpoint, something like a photograph, with a larger project requiring two or three images. In basic terms, the visualiser builds the building on the screen and then takes a snapshot.

Peter Jarvis, from the Society of Architectural Illustration (SAI), says some architects still prefer traditional sketches instead of the "all-singing, all-dancing software", especially when they want to woo a client in the early stages. He feels watercolours have more "integrity" than computers, but agrees that these days visualisers are more likely to be using 3D programmes.

While the profession has become more mainstream in the past five years because of digital techniques, Denby says it's still a career that people tend to drift into and no specific training course exists. The SAI gets inquiries from all over the world from people looking for visualisation courses, and Jarvis's advice is to try local universities or colleges and look for part-time units, for example in 3D modelling.

Like a lot of visualisers, van Herpt's background is in architecture, and he did a diploma in his native New Zealand. He says it's crucial that you have the background: "You need to know how a building is put together and you need to understand architects' drawings. You are often working with architects in their office, so you need to know how they think."

However Denby points out that he has had nothing to do with architecture at all. He went to art college, later working in furniture and interior design until he was approached by a customer who was an architect. He now has his own architectural visualisation company in Leeds. But he agrees you need an understanding of architects and architectural terms, as well as an eye for composition and, importantly, 3D awareness.

Van Herpt says visualisation is good fun, but warns that this is not a nine-to-five job, and people will put in a lot of hours and work late nights. When he hires people he looks for what he calls attitude: "You can teach someone most things but if they have the wrong attitude then it won't work. Most of the skills are learnt on the job and you need to be proactive."

As for Denby, his biggest buzz is from seeing his visuals in magazine or marketing brochures; "I love the job, I just like creating something from nothing."