So, in an adjacent classroom, a group of students wearing 3-D glasses made by Nvidia, a graphics processing firm, dissected a virtual cadaver projected on a screen. Using a computer to control the stereoscopic view, they swooped through the virtual body, its sections as brightly colored as living tissue. First, the students scrutinized layers of sinewy pink muscles layered over ivory bones. Then, with the click of a mouse, they examined a close-up of the heart, watching as deep blue veins and bright red arteries made the heart pump.