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Step by Step: Night at the Museum

Jan 1, 2007 12:00 PM, By Ellen Wolff

A Mammoth Assignment

In Twentieth Century Fox's Night At The Museum, a menagerie of “display animals” comes alive — and heads outdoors from New York's American Museum of Natural History. While that group includes extinct giants such as a woolly mammoth and a tyrannosaurus rex, director Shawn Levy didn't want them to look too scary (this being a family film). But they also couldn't be stylized like the warm-and-fuzzy mammoth in Twentieth Century Fox's Ice Age hits.

Visual Effects Supervisor Jim Rygiel, who earned three Oscars for The Lord of the Rings trilogy, knew the challenges of blending realistic CG creatures into cinematography. He tapped Los Angeles' Rhythm & Hues (R&H), which had animated Aslan the lion in The Chronicles of Narnia, to create a convincing woolly mammoth. “When we started, I was concerned about animating ‘taxidermied’ animals,” says R&H Supervisor Dan DeLeeuw. “There's a definite artistry to that.”

To get a feel for the location, the crew was allowed to wander the American Museum after hours, although they weren't allowed to film. They did capture images of the building's exterior at 3 a.m., which became the basis for a digital matte painting created with Adobe Photoshop. This background was essential for a key scene, where the animals parade outside. “It was an ‘Abbey Road' shot,” DeLeeuw says.

At the same time, he says, “Jim Rygiel shot HDRIs (high-dynamic-range images) while standing in the middle of the street — and scaring me by standing near traffic.” Rygiel's HDRIs provided a lighting guide that R&H used for the scene.

But creating a snowy environment complicated matters. While the crew captured the exterior images, fake snow was sprayed. R&H would later add more CG snow using Side Effects Houdini software to complete the snow simulation.

Back in Los Angeles, R&H's modelers and animators tackled the woolly mammoth. While they had studied lion footage to create Aslan, no such references existed for an animal that lived 13,000 years ago. “It was a little tricky. We had lots of conceptual ideas of what mammoths looked like from paintings. But a lot of that was somewhat impressionistic,” DeLeeuw says. Although Night at the Museum is a comedy, he wanted to avoid creating a woolly mammoth that veered too closely to Sesame Street's Snuffleupagus. “We tried to draw a line between comedy and what we think real mammoths looked like.”

For research, DeLeeuw photographed woolly mammoth skeletons preserved at Los Angeles' Page Museum at the La Brea Tar Pits. “We started with that, and then took our own approach by extrapolating back from elephants. We adapted pictures of elephants onto the mammoth. We also tried to encapsulate what everyone knows about mammoths, including that pompadour hair sticking up on top of their heads.”

Determining the character's scale was also crucial. “Our mammoth was sized to fit into the museum's hallways,” DeLeeuw says. “But it was ‘mammoth enough’ to be true to the size it should have been. As we were designing it, we had turntables with maquettes to look at. I had our designers put in a CG human at the proper height so we could judge the scale.”

To create the fur, DeLeeuw's team reviewed images of the arctic musk ox, which is still a living creature. “On the Internet, we found images that showed how that kind of hair worked,” he says. “But our mammoth was a museum display piece, and it's ‘combed' to look nice. It's one thing to have references for something pristine, versus something that's been out in freezing weather like the musk ox. We had to strike a balance between ratty hair that looked realistically clumpy and what you'd see in a museum.”

Of course, the mammoth's hair had to move believably when it walked, and simulating the dynamics and collisions among hair strands is still not a trivial task. Mistakes would have been especially noticeable in the IMAX version of this film.

“Most people's ideas of animal hair are derived from watching dogs and cats. But this animal was 14ft. tall, so its clumped hair is half-a-foot across. In the simulation, those big, long hairs had to hang with the right amount of weight,” DeLeeuw says. He also recalls telling his crew, “Remember Aslan? Well, this mammoth has a mane like Aslan's over its entire body.”

Autodesk Maya was used for modeling, and then R&H's proprietary keyframe animation tool Voodoo was used. R&H's fur tools have also matured since Narnia, explains DeLeeuw. “We're able to see different versions quicker. We also have the ability to have multiple layers of hair moving better against each other.”

New inhouse software called Lighthouse provided a way to set up all the lighting on the mammoth, and then copy those values over to other elements in the scene. “We didn't have to use a lot of fake lights. We could use the HDRIs. A lot of creative sensibilities of lighting are involved in coming up with that right mix of lights, and not having to put in fake lights to reproduce real lighting.”

Rendering these CG elements was done using R&H's inhouse renderer. “By design, a lot of our renders are multi-layered. Each light is rendered with a separate layer, and within each we have material properties. We had skin in one layer, hair in another layer, then lights, and the effects layer for the snow,” DeLeeuw says.

These rendered elements finally were merged together using R&H's proprietary compositor Icy (for Interactive Compositor.) “We have control in the compositor of all the spectral values. You can say, ‘I want it a little lighter or darker on the hair,’ and then just tweak that. So when the director is there and asks, ‘Can we change that?’ we can. In the past, we'd have had to re-render for a week.”

Credit Roll

Director -	Shawn Levy
DP -	Guillermo Navarro
Visual Effects Supervisor -	Jim Rygiel
For Rhythm & Hues:
Visual Effects Supervisor -	Dan DeLeeuw
Concept designer -	Chris Consani
Modeler -	Shannon Thomas
Textures -	Serena Chang, Bonnie Rosenstein
Prelighter -	Betsy Asher Hall
Rigger -	Matt Derksen
Animator Supervisor -	Steve Ziolkowski
Technical Animators -	Randall Bahnsen, Gene Turnbow
Lighter -	Steve Null
Compositor -	Josh Saeta
Visual Effects Producer -	Julie D'Antoni
Animation Director -	Craig Talmy
Digital Effects Supervisor -	Will Telford

© 2009 Penton Media, Inc.