3-D printers are already being used to create things like bracelets, robot limbs, and personalized chocolate faces. They may soon be able to print you a new liver if yours is failing, or shape moon dust into bricks for human habitats.

However, there’s one slight problem – many models that look good on screen prove fragile in real life, snapping under their own weight when handled, cleaned or shipped.

"I have an entire zoo of broken 3-D printed objects in my office," Purdue University computer science professor Bedrich Benes said in a statement Tuesday.

Benes and his colleagues from Purdue and Adobe Systems Inc. have created a system that assesses a 3D model before printing, automatically detects weak points and fixes them. They described the tool in a paper published in the journal ACM Transactions on Graphics in July and presented at the SIGGRAPH computer graphics conference in August.

One example presented in the paper shows the three ways the system can automatically strengthen a 3D model. In a model of a dragon with a comically large head on a very skinny neck, the system hollowed the model and thickened the neck to prevent the head from snapping off, and added a strut to one of the legs to prevent it from collapsing.

"We not only make the objects structurally better, but we also make them much more inexpensive," coauthor and Adobe Advanced Technology Labs researcher Radomir Mech said in a statement. "We have demonstrated a weight and cost savings of 80 percent."

In addition to figuring out how gravity will affect the model, the tool can also pinpoint places where a person is likely to grasp it. Right now the program only works for static objects, but they hope to develop the program further to assist in strengthening objects with moving parts.

“We believe that our system aids both novices and experts in resolving issues prior to costly printing (both in time and money),” Benes and his colleagues wrote in their paper.

SOURCE: Stava et al. “Stress Relief: Improving Structural Strength of 3D Printable Objects.” ACM Transactions on Graphics 31: No. 48, July 2012.