More design hobbyists, entrepreneurs use 3-D printing

Matt Sullivan, a retired soldier, still has trouble explaining his right leg to strangers.

The shiny chrome surface, embossed with the lightning bolt logo of his beloved San Diego Chargers, covers the calf area of his prosthetic leg, the result of a roadside bomb in Afghanistan in 2010.

At the naval hospital where he was recovering from his wounds and the resulting surgery, Sullivan ran into entrepreneur Scott Summit, who suggested a solution to covering the metal rod that protruded conspicuously from his knee.