Animating a 3D character from scratch is typically laborious and expensive, requiring the use of complex software and motion capture tools. Cartwheel wants to make it as easy as writing basic animations and generate basic movements with AI, allowing creators to focus on more expressive tasks.
“When I started, there wasn't much new in animation,” says Jonathan Jarvis, co-founder and CEO of the startup and an animator himself. “There's a huge problem with having a blank screen, with tons of buttons and options. You can work for hours before finally seeing what the finished product looks like.”
Cartwheel aims to skip the first steps and go from zero to basic movements, so that animators who want to create scenes and characters don't have to spend a lot of time on basic actions like taking a step, swatting a fly, or sitting down.
“We generate and key the movements that come from a motion capture setup. [i.e. animating via keyframe] “On your own, faster. There's a lot of value in getting it out of your head quickly and moving, and then you can pick it up and tweak it,” Jarvis said.
The interface is intentionally simple, just letters and text boxes: you can write anything in there and within a minute or two you'll have a basic but smooth animation that you can then export into your usual 3D editing suite.
You can also check out some live 3D samples on the site, like this little boy boxing and dancing a solo waltz.
Andrew Carr, the company's co-founder and chief scientist, said the model they've built is entirely original.
“We have multiple data sources, all ethically collected, and our own labeller that labels these movements,” he explained. “Movements are represented as a matrix, which is something that's well known in the literature: a matrix that contains pose, duration, velocity, etc. So we associate the matrix of movements with a text description of the movements, and do standard training on movement-language pairs in the same way that we generate images and videos.”
Image credit: Cartwheel
Carr estimates that the resulting animation is “about 80% perfect, on average.” Jarvis says that while the method produces great, professional results, “it does get messed up sometimes.” But it's much faster and simpler than traditional animation workflows, especially in an environment where multiple artists work on a single process, and even small tweaks have to be redone multiple times.
The models they use are not very large, so they are cheap to run and can conceivably be hosted locally.
“This is actually really cool,” Carr says. “For a video model, you're predicting 2,000 by 2,000 pixels at 60 frames per frame, which is a really big problem. What we're predicting is over an order of magnitude smaller than that. It can run on a CPU or an older GPU, and it allows us to train models faster.”
Cartwheel co-founders Jonathan Jarvis (left) and Andrew Carr. Image courtesy of Cartwheel
Jarvis even hinted that eventually it might be possible to render new or revised animations on the fly, the holy grail of interactivity in games, where characters are typically restricted to a set of stylized movements and lines. Camera movements and angles would also be intuitive, and non-human characters are in the plans, though the startup is initially focused on human animations, which are the most commonly needed.
This is similar to how Wonder Dynamics has significantly simplified the process of inserting 3D characters; the company is focused on removing the repetitive drudgery of basic animation tasks, rather than replacing animators and artists. The industry as a whole is embracing AI-related tools as time-saver tools that allow creators to focus on the creative process. At least Autodesk certainly is, as evidenced by its acquisition of Wonder Dynamics two weeks ago.
While it may be a bit rash to speculate on a startup's ultimate fate so soon after launch, Cartwheel will likely follow the same path: get acquired as a promising, powerful feature that could prove an advantage over competitors, but it could also grow into a platform-agnostic tool offering a growing set of services to professional animators.
Either way, the company has secured $5.6 million in seed funding in its first funding round, led by Accel with participation from Khosla Ventures, Heretic VC, MVP Ventures, Correlation Ventures, Pelion VC, and, as is tradition, a handful of angel investors.
For now, Cartwheel serves as one of many prosumer apps that animators rely on for their work, and you can test it out for yourself by signing up for the beta.
“There's this idea that AI is going to replace creative jobs, but as a creative person, I don't think that's the case. It's going to lead to more animation and more motion, more work for each person,” Jarvis says. “And then eventually it's going to trickle down to the big studios and they're going to make amazing things that we never imagined. But there's a level between Pixar and people playing games on their phone, and that's where a lot of the creative work is actually happening.”