Software that helps turn video game characters into real-life figures, using a 3D printer, has been developed by Harvard computer scientists.

Computer figures created without the constraints of the physical world are difficult to print.

So the team developed a tool that identifies ideal locations for a real-world figure's joints.

But a lawyer said if the technology were to come on the mass market, copyright issues could arise.

Three-dimensional printers, which create objects layer-by-layer using materials such as plastic, wood or chocolate, have been used to make toys, jewellery, car parts and even artificial limbs.

But making cartoon or computer games characters was more of a challenge, said Moritz Bacher, one of the researchers on the team.

"In animation you're not necessarily trying to model the physical world perfectly - the model only has to be good enough to convince your eye," he said.

"You can make a character so anatomically skewed that it would never be able to stand up in real life, and you can make deformations that aren't physically possible."

The researcher said although most video game characters were created with skeletons that help animators turn the figures around on the screen, they were different from those in real-life objects.

"As an animator, you can move the skeletons and create weight relationships with the surface points, but the skeletons inside are non-physical with zero-dimensional joints - they're not useful to our fabrication process at all.

"In fact, the skeleton frequently protrudes outside the body entirely."

The team developed software that identifies the ideal locations for a computer-game figure's joints.

It is difficult to understand where the joints are just by looking at a character in 2D.

The software then optimises the location and the size of the joints for the physical world and generates the best possible model.

It also analyses a computer character's skin and enhances the texture, making it possible for details such as scales on a snake to appear on a printed object.

The researchers say the tool could be useful for artists and animators to experiment with a moving character.

"If you print one of these articulated figures, you can experiment with different stances and movements in a natural way, as with an artist's mannequin," said Mr Bacher.

3D printing has been used to print various objects - even food
But if the technology were to come on the market for the mass consumer to use, a major issue could arise - copyright.

"In principle, there is nothing illegal about this technology as it has not been designed in order to infringe copyright or to avoid any anti-piracy measures," said Mark Corran, a solicitor from Briffa, a London-based intellectual-property law firm.

"Commercially, I'd expect that the intention is to license this hardware to, for example, Microsoft or Sony for use with their devices.

"If the device was authorised by Microsoft or Sony, then there should be no infringement.

"However, where someone has created the images for a character in a game, which will be stored within the code of the game,… using this technology to make a 3D copy of a 2D on-screen image for the character would be an infringement."