One of the earliest (if not the first ever) 3d rendered video is about a hand.
Created by Ed Catmull, (the founder of Pixar) the video features an interesting segment of making-of:
“The best part of this film is not even the 3D rendering itself, but the outtakes and “making of” footage that has been interwoven throughout, including footage of a plaster replica of Ed’s hand onto which he is meticulously mapping the polygon vertices that make up the three dimensional model (around 1:30). That’s really remarkable. The math that we take for granted for rendering 3D was being invented, real time, to create this video. (Ed’s credited for having working out that math to handle things like texture mapping, 3D anti-aliasing and z-buffering.)”
More info here.
Via: Roberto la Forgia and Kottke.
Actually, check this from the cornell program of computer graphics in 1971. It’s rendered. I think the first real 3d animations were created for a NASA flight simulator in the late 60’s that allowed the apollo astronauts to practice the capsule/lunar lander docking sequence. http://www.graphics.cornell.edu/online/cip/