We've written before in our roundup of Disney animation secrets about how Pixar used AI spiders to create the cobwebs for Toy Story 4. It's a fact that never ceases to amaze people, but today's it's creating a whole new debate: was it really AI?
To recap, the cobwebs you saw in Toy Story 4 weren't created by human artists or pulled from a reference library. They were generated by digital spiders that don't actually exist. Pixar dubbed these critters 'AI spiders' since they were created mathematically as a form of machine learning.
Pixar’s Dylan Sisson told us at our own Vertex event back in 2021 about how technical director Hosuk Chang's team created the swarm of AI spiders in Houdini so that they would weave webs like real spiders would.
"They would go into these nooks and crannies and start weaving webs," Sisson told us. "We’d render these webs out and that was pretty helpful." In the video above the AI spiders are shown as red dots.
Such detail would normally have to be created manually, which would mean a huge large amount of work to create the number of cobwebs the team wanted in the movie. Usual shader workflows may not provide the necessary detail in an animation where the camera is so close. The AI spiders streamlined the process, adding cobwebs in a realistic manner, while cobwebs that characters interacted with were still done by hand to ensure realistic behaviour.
Today, just a few years on, AI has become almost omnipresent, but it's often used to refer to a specific type of generative AI – the kind of tech behind AI image generators. That's leading some people to argue that other AI solutions weren't, in fact, artificial intelligence after all. The VFX artist Rassoul Edji recently reposted Pixar's spider video on LinkedIn only for many people to argue that calling the spiders 'AI' was incorrect.
It seems that if we don't end up in a war of humanity vs AI, we'll end up in a war over the definition of the term.
You can learn more in Chang's SIGGRAPH 19 paper on dust and cobwebs for Toy Story 4. For more Disney tricks, see our guide to Disney's principles of animation.
