One weird trick animators use to make movement look fast

Some seemingly normal video game animations have a single still frame of body horror snuck in. They’re called smear frames. There was a time when smears were vital in games, but they don’t happen much anymore, and there’s a very good reason for their disappearance.

Smears harken back to the early days of modern animation, when artists would study live-action film to get a better sense of how to depict action realistically. They discovered that when somebody is moving quickly, film doesn’t capture clear-cut images. Instead, the movement translates to blurs of color. Animators experimented with this imagery and came up with smears to mimic this optical illusion. It’s particularly visible in highly stylistic cartoons like Looney Tunes.

This stylistic approach to speed can be seen in modern games that draw on that retro animation aesthetic, like Cuphead and Skullgirls. But it’s also visible in franchises you wouldn’t expect. In particular, Capcom fighting games from the ’90s and 2000s, especially Street Fighter, relied heavily on smears to sell fast, snappy action. Although we don’t think of Sonic the Hedgehog as being an homage to old Warner Bros. cartoons, the franchise uses smears to get the same kind of satisfying gotta-go-fast motion.

It’s a lot harder to do smears in 3D animation than it is in hand-drawn animation. Games like Crash Bandicoot and Overwatch put in the extra work, but using skeletons and meshes means a lot more finessing is required to get a smear to look, and feel, good.

Watch the video above to see some amazing still smear frames, and to learn how they work and why they’re so hard to do in 3D animation.