One Thing I've Learned From Sprite Fright: Rigging Edition

Sprite Fright is Blender's new Open Movie, now in development. You can follow progress and updates on the Cloud. In this post, we talk to Demeter Dzadik, Sprite Fright’s talented Rigger (the highly technical job of providing "skeletons" for 3D models so they can be animated). The master of puppets shares one thing he’s learned while working on Sprite Fright.

“Actually,” says Met. “It’s not one thing. It’s the thing.”

Before we get to Met's rigging revelation, some terms for those new to animation. “There's two ways to go about rigging characters,” Met explains. “Procedural rigging, which is when you use code to generate a rig. And non-procedural, which is just doing stuff manually.”

Got it? Got it. So what was Met's big learning?

“It's that you need to have strong support for a non-procedural approach even within a procedural system.”

Unless you're a rigging guru, that statement probably requires some unpacking.

Met is happy to oblige.

Why Hybrid Rigging?

“Procedural rigging is a trade-off between convenience and control,” Met says. “So if you’re going to opt for procedural rigging, and sacrifice the control that comes with manual rigging, you also need the option to regain that control in certain situations. For example, in Sprite Fright, the characters’ limbs are fully procedural. That’s because they’re simple and pretty much the same. But the characters’ faces are so unique and demanding that they have to be mostly rigged manually. And that means that the rigging system has to support manual options too.”

A Solution For Your Rigging Woes

So Demeter developed his own system. Weighing in at a whopping 926 commits (and counting), it’s called ‘CloudRig.' While CloudRig has been around for a while, Sprite Fright pushed Met to add whole new realms of functionality. He had a sound basis for this: CloudRig is an extension of Rigify, a well-known add-on that allows artists to easily create "bones" for their characters -- which in turn allows those characters to be animated.

Demeter: "In Rigify, you have a base rig that permits you to enter some specifications, then you press a button and it comes up with a generated rig from those specifications. So the idea with Cloud Rig is to allow you to add a bunch of extra stuff into that process. Rigify already has a ‘super_copy' rig which lays down some foundation for how procedural and non-procedural rigging can be mixed. CloudRig just needed to build on this."

For Met, this goes against the fundamental idea behind procedural rigging. “It took me a while to accept this,” Met says. “For a long time, I was trying to come up with rules that are shared across all the characters’ face rigs, and it’s just not possible. There are too many moving parts to make the system fully procedural.”

Get Your Cloud Rig Here

The prototype of Met’s CloudRig is already on the interwebs here, free for you to try. “I haven’t shared it much yet,” Met explains, “So there hasn’t been much testing yet. But it's pretty much functional. I have a to-do list for it, but most of the things on the to-do list are fairly cosmetic.”

Demeter’s CloudRig is an example of Blender Studio using Sprite Fright to push the production pipeline. “I intend to keep using CloudRig for future films forever,” says Met. “And I hope that if more riggers join Blender Studio that they like the system. I think it’s good.”

For those who’d rather experience the full version of CloudRig, check-in around October, when Sprite Fright is released. Demeter: “That’s when I will be able to say, all these characters were rigged with CloudRig, so anything should be possible with it. If you can't do what you need, surely you're not using it right!” He grins. “Or maybe it’s just under-documented. In that case, you can let me know!"

More Met

To keep up with the CloudRig’s progress, be sure to follow Demeter's updates on the Sprite Fright production logs.

And for an overview of the thinking behind Sprite Fright, check out this post on its design language, this one on storytelling, and this piece on movie influences.