Identify a consumer need, design a solution under a certain price, and sell it online.
Those were the basic guidelines for engineering students in Mechanical Synthesis 2250, an introduction to product design. The sophomore-level course, co-taught by mechanical engineering professors Hod Lipson and Zellman Warhaft, took a new twist this year: For the first time, students had their prototype designs printed on Cornell's 3D printers in Upson Hall.
As a final step, students sent their designs to a 3D printing company like Shapeways or Materialise, where anyone can order and buy the products, custom-printed in materials like food-grade ceramic, metal and plastic.