The human touch, revved up on screen

Paper sketches and clay models are still crucial in the design of a new car, but increasingly computers are entrusted with creating 3D models that are cheaper to `crash' and thus enable safety concerns to be taken on board at a much earlier stage. David Fox reports.

"Designed by computers, built by robots, driven by idiots", is an ageing joke which has never been true. Those undistinguished cars that dominate the market were designed by people. However, car designers do increasingly use computers to cut the time and expense of developing new cars. So much so that Ford created its well-received new Puma sports coupe in just 135 days without a pen touching paper - the first time it has designed a vehicle completely on computer.

Besides saving time and money, it should make it easier for manufacturers to produce more interesting designs based on existing platforms (the Puma is 70 per cent Fiesta). It also improves build quality and, importantly, safety, where the ability to conduct quick, cheap crash simulations using virtual cars has had a huge impact. A danger is that the speed of turnaround could lead to cars being produced as fashion items, which become dated and lose their value more quickly.

Avoiding this is one of the many limits within which Rover's Gerry McGovern has to design. As chief designer of the new Land Rover Freelander, which makes its first British appearance at tomorrow's London Motor Show, he wanted to create a radical design by four-wheel-drive standards while remaining true to Land Rover tradition. Therefore, Freelander has a clam- shell bonnet (like the Range Rover), a kicked-up roof line (the Discovery) and rear lights which are a modern interpretation of the Defender's.

However, McGovern is a traditionalist when it comes to computers. As a creative tool, he believes they lack the flexibility of pencil on paper.

"At the moment, computers lend themselves best to doing interior components and wheels, and other small parts, where details are important. But when it comes to the exterior, we still use drawings because there is a lot of passion and emotion involved in developing the look of a car," he says.

For the Freelander, the sketches were turned into full-size clay models, with designers and model-makers working closely together. Once Rover's board decided which design to go with, technology moved in and hundreds of points on the clay interior and exterior models were translated electronically into a 3D computer model. This allows the designers to build up and refine a database of parts, for direct output to the tool makers, which McGovern sees as "the beauty of working on computer" as it considerably speeds up what was a very labour-intensive process.

At Ford, which claims to have more computing power than any other car maker, computers are used throughout the design process and even to create a "virtual manufacturing" system to examine production flow. Painting on screen allows designers to build up layers of colour and texture, "and if you make a mistake on one layer, you can easily make changes, so you are not afraid to do something which might mess up a sketch as you would on paper," says John Gardiner, Ford's manager for design and technology. He believes this "leads to greater creativity and innovation".

Then Alias Auto Studio, a 3D package, is used to create a virtual model, which is animated on Silicon Graphics' Onyx Reality Engines so that senior management can view almost photo- realistic animations of a car to decide which ideas to go with. Ford claims to have more animation power than Disney used to make Toy Story.

"A single designer can go from a 2D sketch to an animation which looks like a real car in about two to three weeks. To do the same traditionally would take about 12 weeks on clay and require about 12 people making it," Gardiner says. "For the time and effort of producing a clay model you can do 10 to 20 animations."

But, he admits, "you will always need some form of 3D models which you can look around and feel". This may not need to be physical. Ford is working with Glasgow School of Art on images they can touch (probably using a glove). This could take five to 10 years, so for now the computer data drives a new five-axis mill at the Dunton design studio, which creates a physical model. As this only does 80 per cent of the job, models must be finished by hand.

Rover also uses five-axis milling machines to cut the finished models for final approval, and while McGovern says it is technically feasible to do everything on computer, going straight from screen to producing finished metal, he believes such an approach would be incredibly risky. "We build models to make sure that what we're going to make and invest millions in is going to be right." Only life-size models give that confidence.

Computers also play a vital role in safety, with virtual crash tests allowing the engineers to develop better impact zones, as well as checking sight lines so the driver can see what's coming. Up to 80 per cent of Ford's crash testing already runs on computer, saving up to pounds 300,000 for each hand-built physical prototype it need not crash, and a further pounds 40,000 of crash test costs. Each computer model crashed costs about pounds 120 and takes just 15 minutes to run on a 16-processor Triton computer. (It would take 15 weeks on a home PC). Within three years costs should be pounds 8 per computer test. Because it is so cheap and easy, it allows them try ideas they wouldn't otherwise consider, and to look at safety earlier in the design process. Gardiner believes it will reduce the number of physical prototypes Ford has to build by 90 per cent over the next two years.

Still, as a creative tool, McGovern believes paper allows greater flexibility. "At the start of the creative process we capture the passion and creative tension better through drawing than using computers," he says. But he became a car designer because he loved to draw cars and admits that some young designers prefer using computers - even if they still tend to start with sketches, as "you need the artistry and creativity you sometimes don't get using computers. If you're not careful you sometimes get a cold, mechanical look".

He maintains designing on paper and clay is "more human", but says the technology has reached the point where the two methods are interchangeable and even inextricably linked. "But let's do it in a controlled fashion, so we can get the best out of digital ability and creative ability", he adds.