A state-of-the-art 3D package has been developed by researchers in Germany to enable forensic experts to accurately reconstruct dead people's faces, according to a report in New scientist.

Traditional methods of reconstruction have been painstakingly laborious, taking days to build up layer upon layer of clay. Experts also had huge problems creating and changing expressions on the moulds, which is often needed to aid witness recognition.

But Kolja Kahler and Jorg Haber of the Max Planck Institute for Computer Science have developed a computer program which will significantly simplify the process.

The software creates a 3D model of the skull and then places flesh over it. Previous data collected over the decades — which gives scientists pretty accurate estimations as to how thick the flesh should be at each point on the skull — have been pre-programmed into the software, along with adjustments for age and race.

A generic virtual head simulates the 24 facial muscles in the skull which are responsible for emotions, allowing the skull to smile or frown, for example. The features of the customised head are then adapted to the virtual one, creating a fully animated head.

"We can show subtle facial expressions, and that's something that the traditional clay sculpting method cannot do," Jorg Haber told the New Scientist. "With our system, it's just a few clicks of the mouse, and you can change the expression."

The research was presented at the Siggraph 03 computer graphics conference held in San Francisco last week.