Claymation

Clay animation or claymation is one of many forms of stop motion animation. Each animated piece, either character or background, is "deformable"—made of a malleable substance, usually Plasticine clay.

Traditional animation, from cel animation to stop motion, is produced by recording each frame, or still picture, on film or digital media and then playing the recorded frames back in rapid succession before the viewer. These and other moving images, from zoetrope to films to video games, create the illusion of motion by playing back at over ten to twelve frames per second. The techniques involved in creating CGI are conversely generally removed from a frame-by-frame process.

Each object or character is sculpted from clay or other such similarly pliable material as Plasticine, usually around a wire skeleton called an armature, and then arranged on the set, where it is photographed once before being slightly moved by hand to prepare it for the next shot, and so on until the animator has achieved the desired amount of film. Upon playback, the mind of the viewer perceives the series of slightly changing, rapidly succeeding images as motion.

A consistent shooting environment is needed to maintain the illusion of continuity: objects must be consistently placed and lit, and work must proceed in a calm environment.

Producing a stop-motion animation using clay is extremely laborious. Normal film runs at 24 frames per second (frame/s). With the standard practice of "doubles" or "twos" (double-framing, exposing two frames for each shot) 12 changes are usually made for one second of film movement. Shooting a 30-minute movie would therefore require making approximately 21,600 stops to change the figures for the frames; a full-length (90-minute) movie, 64,800—and possibly many more if some parts were shot with "singles" or "ones" (one frame exposed for each shot).

...
Wikipedia