The CG secrets behind General Grievous’ cape.
If you’ve already grabbed issue #1 of befores & afters in print, then hopefully you will have read ‘The great capes’ story inside the magazine. It’s a look back at the early CG capes, and the cloth simulations behind then, made by visual effects studios. One piece of CG clothing featured in the print article is Count Dooku’s cape made by ILM for Count Dooku for Attack of the Clones.
For the story, I talked to Juan-Luis Sanchez, credited as a digital model development and construction artist on Clones, and subsequently as a digital clothing supervisor on Revenge of the Sith. In addition to the work on Dooku, he also told me in our interview about the cape—or cloak—work for the CG character General Grievous in Sith, and I wanted to share that story here for online readers.
It’s a fascinating tale about thinking about cloth sims all the way back to cloth patterns (like we do now), dealing with a late character design change, tailoring the cape during animation and faking the character’s ‘cape silhouette.’ Here, Sanchez outlines just how Grievous’ final CG cape came to be at ILM.
Juan-Luis Sanchez: By the time we got to Episode III, we were starting to experiment more with actually thinking about patterns. This was driven by [technical animation supervisor] James Tooley. He was thinking, ‘Well, if this were a pattern of cloth, what would it actually look like flat? Let’s model that first and then sim that onto the characters.’
For Grievous, we did a quick study of what a cape would look like if it was a single pattern. And I remember we laid out some kind of clothing we had—it wasn’t his actual cape—but it was almost life-size and we laid it on the floor and unfolded it and went, ‘Okay, well this is literally what we have to make.’ So we gave that to the modelers and said, ‘This is what we want to model.’
At the time, the original design for Grievous had him as this very regal, very tall, very upright vertical character. We put this initial modeled cape on him and it kind of lay around on him really nicely. And then as the character work developed, he became a lot more villainous and hunched over, almost a classic 1920s movie villain, and the cape started to drag along the floor. I liken it to when you’re a kid playing Batman or Superman and you’re dragging your sheet-cape behind you on the ground. And the thing is, it just made Grievous look ridiculous!
This meant that we went through an interesting process of tailoring the cloak to work with him (the artist who did most of the setup was Scott Jones). And there were a couple things about that that were really cool. In terms of modeling, the character had this fantastic mix of metal and ceramic and organic pieces and the modelers had lovingly spent six months, nine months, a year, I think, on this character. And so then suddenly we came along, we just stuck a cape on it, and you couldn’t see their work! It was like, ‘Oh no, what have we done!?’
Anyway, that was one thing, but we also had to work out how not to have the cape drape down around him as he walked. Because, remember, the animators at that time were not seeing previews of any of this stuff. They were not seeing where the cape was going to go or anything. So, what we did was we came up with two modes for the cape.
The first mode was where the cape would drape in front of him. George Lucas wanted him to be playing with it and pushing it out of the way with his hands and holding it up in front of him. So we came up with this mode where it draped down over his wrists and then he would push it out of the way or sweep it out of the way.
Then we also came up with this mode where—well, Grievous had these hooks and when he bent his elbows, he had these spikes on his forearms that extended past his elbows. So we said, ‘What if we hooked the cape over those spikes?’ And that meant it could reveal all the beautiful modeling and geometry he had underneath. That actually worked really well.
Depending on the shot—there was sometimes continuity challenges where he’d, say, get into the lift with the cape in one configuration and come out of the lift with the cape in a different configuration. But nobody ever, ever questioned it because it just worked.
The other thing that was interesting was Grievous’ silhouette that was made by the cape when he was standing. Because of his understructure, the thing is his cape wouldn’t really have looked like that just standing still, so we didn’t collide our cape with his actual body geometry. Instead, we built a fake almost Michelin man set of rigid pieces that the cloth would collide with.
What was under his cape for his shoulders was more like an American footballer. He had these massive shoulder pads essentially, but the geometry underneath was nothing like that, of course.
There’s this one shot where he shakes off the cape in order to fight Obi-Wan, and it’s a beautiful shot where he just shrugs and the cape disengages via some magical mechanism that you never noticed and it just slowly comes off him. But if you look closely, you’ll see the silhouette there, when he shrugs off the cape. It’s just not supported in any way by the body geometry that’s underneath.
It’s just one of those little illusions that I was worried about. I thought, ‘How is this going to work? This is not going to work.’ But nobody has ever questioned it.