Avatar: The Game Changer

Find out from Joe Letteri and others how Avatar has created a VFX revolution.
Posted In | Magazines: VFXWorld | Site Categories: 3D, Films, Visual Effects
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Beautiful daytime plants could become bioluminescent at night with the flip of a switch.

For the animation, Weta put a lot of effort into the facial solves and tracking "because one of the problems with the way that we were doing it was you've only got a single point of view using one camera," Letteri continues. "Ideally, from a technical point of view, it would've been good to go with two or more cameras. But from a performance point of view, that was going to add weight, it was going to slow down the process to changing out drives and it was going to be cumbersome for the actors."

Weta also created a new optical solver for the eyes to track them and paid a lot of attention in animation to the movement to compensate for what the solver couldn't achieve.

FACS (the Facial Animation Coding system developed by Paul Ekman) was utilized once again by Weta. But one of the problems with FACS is that it doesn't cover dialogue. And so that came as a secondary layer, where the motion editors and animators looked at the data coming in and had to figure out what the track was doing and how to solve that. It's really hard to track the shape of a lip because it just changes constantly. So the system was built as a big solver that you could input training data into so that the facial editors would try and interpret what was going on and keep adding to the system until it converges on the right answer, and then have the animators go through it again and take another pass with the rig and make sure that everything behaved properly and worked in the right combination.

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ILM had to raise its game for stereo in matching focal length precisely and doing very accurate tracking.

In building this whole world, Weta had hoped to at least create the plants procedurally, but ended up hand painting everything to make sure that it was of the highest quality and uniform in 3-D space.

They additionally adopted a global illumination system for lighting. "We came up with a system based primarily on image-based lights but then converted the whole system to spherical harmonics," Letteri explains. "What that meant was we could pre-compute all the lighting contributions in a scene and then put the characters and everything in with the lighting and the TDs could move the lights around. It would tell you what the influence was of all the objects around each other. And you could solve that in a global sense."

A new full-on compositing system was devised as well for 3-D. "We started outputting all the depth information for everything we were rendering, so you don't need to rely on mattes anymore," Letteri adds. "You know where everything is in space and can figure out the relationships. That's really important for things like the jungle, where you've got lots of plants and you could layer them in the right order based on depth because you're dealing in pixel to pixel to pixel. That will become standard for compositing from here on out because of the flexibility, even if you're doing a non-stereo movie. It's just easier to composite in 3-D than in 2-D."

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ILM created a tool that lets you custom tailor a high quality explosion that has controllable behavior and can tightly interact with CG objects.

Yet Weta still required vfx assistance and received great collaboration from ILM, Framestore, Hydraulx, Pixel Liberation Front, Blur Studio, Buf Compagne, Hybride, Prime Focus, Halon, The Third Floor, among others.







Comments


You certainly deserve a round of applause for your post and more specifically, your blog in general. Very high quality material

Boabesehope (not verified) | Wed, 07/13/2011 - 14:06 | Permalink

Yeah, I agree that this film is insipirational. I am a film director myself, and i've always made films without ANY visual effects, being completely against it. After watching Lord of the Rings - i started THINKING about VFX as a very powerful tool. Its very powerful. After watching Avatar, I was convinced that only films that involve VFX will be interesting because finally, a director has no limits to his imagination , and it is the imagination and limitless fantasy that is of interest to the audience. The only question is the price.

<a href="http://www.evildrome.com/">Hotfile Downloads</a> (not verified) | Tue, 06/08/2010 - 15:02 | Permalink

it's an fantastic articles, thanks Letteri for providing the in-depths into the making of this amazing film. Really wonderful!

pradipta (not verified) | Wed, 04/14/2010 - 01:08 | Permalink

WOW Wow...
Thanks for the great fantastic article.
James Cameron and everyone who worked on this incredible movie
Thank you very much for my biggest inspirations

ebru (not verified) | Sat, 02/27/2010 - 13:26 | Permalink

Strangely, this is exactly why I have written an article on this subject (Virtual Cinematography). While no one would want to hear that what was done with those truck loads of equipment, can be done with a car load today... it actually can be done.

 

Avatar just re-coined terms like virtual cinematography to something fancier like "simul-cam" and Hybrid cam etc.

 

Trackable physical cam rigs were there since way before, here's some links in this article on the subject especially for indie film makers to investigate.

http://realvision.ae/blog/2010/02/virtual-cinematography-was-the-matrix-...

 

Hope it helps.

realvision | Wed, 02/24/2010 - 20:04 | Permalink

Only really rich people or high budget productions can pull things like this off. Even a really low quality 3d production takes ALOT of money because it requires a full motion capture studio. Not only do you need a few cameras, but if you're going to be running and doing long distance things the equipment will be way too much money for any indie film maker to even think about. You can argue that motion capture is becoming cheaper, but really its not going to be anywhere near what we can afford for a long time. So no, I don't think its a game changer because only top studios will be messing with this tech. I wish I could make a 3d show, but you cannot do that simply from your mac g5, maya, final cut pro, and after effects. You need millions =(

Deranged (not verified) | Tue, 02/02/2010 - 22:56 | Permalink

Yeah, I agree that this film is insipirational. I am a film director myself, and i've always made films without ANY visual effects, being completely against it. After watching Lord of the Rings - i started THINKING about VFX as a very powerful tool. Its very powerful. After watching Avatar, I was convinced that only films that involve VFX will be interesting because finally, a director has no limits to his imagination, and it is the imagination and limitless fantasy that is of interest to the audience. The only question is the price. Its so expensive! ssso expensive!

director (not verified) | Wed, 01/13/2010 - 09:03 | Permalink

you have made a good job for many of us, vfx enthusiastics, students and pros.

Thnak you

Albert Jofre (not verified) | Mon, 01/11/2010 - 04:23 | Permalink

This movie is really beautiful and a big thank to James Cameron for offering us such a masterpiece.

webcam gay

michel (not verified) | Thu, 01/07/2010 - 09:35 | Permalink

Wow, I have yet to see this movie and I am so excited to see the new elements being implemented into live action/CG. James Cameron has done the unthinkable, well the unthinkable to most. Cant wait to see this movie!

I wonder if he has any thought on a 2d production like this and could it even work?

Ken Lemottee (not verified) | Wed, 01/06/2010 - 12:54 | Permalink

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