How animation works: frames, keyframes and the illusion of motion

Frames per second

Cinema traditionally shows 24 frames every second. Hand-drawn animation often draws a new picture for every second frame (“on twos”), holding each drawing for two frames.

Keyframes and in-betweens

Animators first draw the most important poses — the keyframes. The drawings between them, the in-betweens, complete the movement. In computer animation, the software can calculate the in-betweens.

Main techniques

• Hand-drawn (2D) — each frame drawn and coloured.
• Stop-motion — models or puppets moved a tiny amount and photographed, frame by frame.
• 3D computer animation — models built and moved in a computer, with virtual cameras and lights. The games on this site use the same ideas in real time.