McG wanted new Terminators that were beefier and more imposing. All images © 2009 by Warner Bros. and courtesy of Industrial Light & Magic.

After ratcheting up hard body surfaces on Transformers and making more finely textured armor for Iron Man, Industrial Light & Magic came up with some new shading, lighting and rendering tricks for Warner Bros.' Terminator Salvation, which introduces a gritty, post-apocalyptic twist from director McG to the famed franchise.

Overall, ILM supplied 366 shots out of 1,300, with assistance from Asylum (including facial replacement for Sam Worthington's Marcus Wright), Rising Sun Pictures (including CG Hunter-Killer explosions and underwater submarine work) and matte paintings from Matte World Digital. Charles Gibson served as overall visual effects supervisor.

"I'm worried that I'm painting myself into a corner with these robot movies," chuckles Ben Snow, ILM's visual effects supervisor, who also worked on Iron Man and is now in the thick of it on Iron Man 2. "But we're able to mix up techniques, which is always good. McG definitely wanted to create something new. The Terminator franchise is beloved and always fun to work on. I think there was a little bit of a conscious effort [from everyone] to live up to the legacy of the earlier films in terms of spectacle and effects and to also explore this post-apocalyptic world for the first time. And to build on the idea that no one is safe from these machines -- they're relentless. You can be in the water, the sky, the ground and they're going to get you."

Indeed, according to Snow, McG not only looked to the Terminator films for inspiration, but also Mad Max, Children of Men and Cormac McCarthy's novel, The Road, which has been adapted by director John Hillcoat for an Oct. 16 release.

"On this film, there was a very harsh look," Snow continues, "and what's interesting is that it can be hard on the CG, particularly with the integration issues because they're taking the dynamic range of the film and basically contrasting that up. It tends to throw out the CG a little more easily than if the film was less harshly processed. With that in mind, and because we knew that we'd be shooting in harsh desert environments as well as in the factory [at the end], which is very dynamic, we knew we needed some new materials.

ILM integrated an energy conserving shader set in RenderMan in conjunction with an HDRI lighting approach to get rendered images with a more believable real world look.

Essentially, what we did was integrate an energy conserving shader set in RenderMan and used that with a higher dynamic range image-based lighting approach to get rendered images that had more of the dynamic range of the original film [that was shot]. I'm definitely glad we did that and we'll certainly be using it all the time from now on. It's not super fast to render, but it'll get faster as we optimize. But it did mean that we were more accurately modeling the physical reality of shining light on metallic objects. I think it enabled us to get more believable real world materials."

Philippe Rebours, ILM digital production supervisor, adds that this new shader system helped put their tools more in sync. "Before, let's say that you have an environment and you want to reflect [your objects]. So in the shader you would use the ray trace function that hits the geometry and that gives you a color or value. But when you use the light, you create a light shader, which is a spotlight or area light, and so the material shader will call that shader and that will give you another value. So there was a difference between diffused and ambience, the same way there's a difference between specular and reflection. However, in real life, specular is reflection. And so we decided to recombine everything in a real world way, which would give you the same result and be more accurate."

For example, when John Connor (Christian Bale) fights a T-600 outdoors in the beginning, ILM noticed that the crew used a big diffuser in front of the sun to make it harsher. This was part of McG's desaturated look (with the help of a bleach bypass DI treatment). So when Rebours and his colleagues did the lighting, they recreated the same look in CG. "We had environment lights and we had an area light to represent the sun that had the same size as their diffuser. And we got something that looked very realistic, very quickly. And in some cases, when it's not a close-up, you definitely have the T-600 in contact with the ground. We textured the ground and there was no difference texturally in the way the ground would bounce and reflect with real light. In previous movies, in our previous set of shaders, we could have a very complex specular highlight because we would use multiple levels of speculars and different colors. However, the reflection [that we got] using the reflection [mode] wasn't as complex, so you had a mismatch of complexity in your material. But now we have the same complexity for everything. The same goes for interiors as well."