Life Of Pi's Visual Effects Are Extraordinary. Here's Why

Life Of Pi's Visual Effects Are Extraordinary. Here's WhyLife of Pi will finally reach UK cinemas tomorrow after a successful, and well-lauded run in the United States. Last week, I got to chat with Bill Westenhofer, the film's visual effects supervisor.

Westenhofer's work in the film, and that of his colleagues at Rhythm and Hues, is often astonishingly good… and at other times, you might not be astonished at all simply because you'll stop seeing the FX work and just see a Tiger, a boat, an incredible sea and a heartbreaking sky and believe that they are real.

Here is some of what Westenhofer had to tell me about the film's FX, where they are and how they came to be.

I was the overall visual effects supervisor on Life of Pi. I started at the very beginning and had to break down the script. I had to come up with the methodologies of how we would shoot the movie and work with the various departments to work out the tech aspects of using the blue screen stage and the water tank, the costuming.

Once we were shooting I had to make sure the actor had cues of where the tiger would be, that he had all of the information needed to carry out his performance or a question arises. If it looks like something isn't working I would offer visual effects suggestions of how we could fix it in post. And then when post began, I directed the entire visual effects team technically and creatively to achieve the required results.

86% of the time the tiger is pure illusion. A shot is either digital or real and we don't jump from one to the other within a shot. We may cut back to back but never within a shot itself does the tiger transform.

The biggest thing in making the tiger seem real is Suraj [Sharma who plays Pi, the human passenger on the boat], and making sure he's performing there. We started with carefully pre-vis'ing everything to make sure we had all of the shots planned. Ang worked with the pre-vis team for about a year and embraced it. Here, what we had in pre-vis was definitely what we were going to shoot and that's not always the case with different directors. This meant we could show everyone, from Suraj to the camera crew, where the tiger is going to be and what it's doing.

Life Of Pi's Visual Effects Are Extraordinary. Here's Why

If there needed to be physical response we actually had our animation director [Erik De Boer] don a blue suit and hop in the boat. Where Pi is trying ward of the Tiger with the pole, Erik was the one grabbing hold of the other end. Sometimes it took a couple of people because tigers are pretty damned strong.

We had some ability to 'weight shift' and create splashes as the tiger walks around on the boat but, interestingly enough, we took a lot of research and took a lifeboat and a raft out onto the ocean and saw that as soon as there's any degree of water movement, the weight of the water lifting and floating the boat has a much stronger effect than even a 500 pound tiger. One cubic foot of water is a pretty good percentage of that. We used the weight shifting primarily for when the ocean was really calm, that's when you could sense it.

You want to do things on set as much as you can but there are pitfalls. It does restrict your animation afterwards if somebody didn't tie-in properly, so there were oftentimes it was easy to completely replace the tarp [with CG] so we could have the tiger depress it on screen. There were even times where we just replaced the entire lifeboat to get better integration with shadows and for little details.

I would credit the reality of the eyes to a tremendous amount of research. One of the reasons I wanted real tigers on set at all was to set the bar so we couldn't cheat, there was always something that was going to be cut in that we had to match, something that gave us a definitive target. And then having them down there, we got hundreds of hours of reference of them on the real location and performing. We got cameras in there and filmed the tiniest of details. With tigers the eyes don't rotate in the socket nearly as much as with a primate, for example, so we found at first that when we tried to stick at this too closely, it looked bad. But nothing is ever as simple as that, and they do roll around some, so it came down to studying this.

On Narnia for example, we knew we needed reference of a lion but the most we got was a day with the lion and a trainer and we tried to do as much as we could but there's a limit to how you can get. Here we had ten weeks and we could ask the trainer "When the tiger is freaked out, how would he react?" The surprise is that a tiger, when he's nervous, is going to act as nonchalant as possible and try to show you that he's not scared, that it's part of his defense mechanism. He's going to show you that he's not phased.

It's a story point that the animals are not anthropomorphic and behave as real animals. I sat with Ang and told him "For every one of the shots I'm going to find something in the reference to base it on." If we didn't have the clips we'd possibly fall into how humans would react and that would betray the whole point of the movie.

Every shot of animal performance started with direction from Ang. It started during the pre-vis stage with some basic choreography and talking about the actions. We also talked to the animal trainer about what behaviour would make sense and then wouldn't. Ang would then give us some basic camera instructions, we'd block it out and show him to get his adjustments. We'd show him reference material and say "Here are some things that work" to see what he liked. It was a continual evolutionary process.

The primary visual effects vendors on Life of Pi were Rhythm and Hues and MPC. MPC did the storm sequences – the ship sinking and the other storm. We then did all of the other oceans. And these oceans were actually as technically challenging and technically rewarding as any of the animal work. It's kind of funny that I'm reading the reviews and the cinematography gets a lot of credit, and Claudio did a great stuff, but for most of the stuff on the ocean, we're starting with a tank and a blue screen and it's our job to make the sky, to make all of the creative choices for how the ocean would look.

Ang did say he wanted the ocean to be a character which is just speak for "The oceans are important and set the mood for the sequences" so we had to be careful about the choices we made. We did as much research on the ocean as we did the animals. We went out on a Coastguard Cutter into a 50ft storm surge, which was an experience. From a technical stand point, because the film was shot in native stereo [3D] and the water was the hardest thing to solve. Every time we wanted to keep some of the tank water we had to blend that with the visual effects water as closely as possible. We had to get the cadence of the waves in the tank water to continue into the digital side and that is very challenging.

We started the skies with a general discussion about what time of day it would be, but from an aesthetic stand point, Ang looked at this as an art project so we did start with photography. Every sky started from a photograph but there was always the license saying "This is Pi's recollection of the journey" so we could add a little fantasticism to it. Especially, perhaps, the morning he wakes up and the ocean is completely still – though there have been some sailors who have talked to Ang and told him that does happen on the ocean and nobody believes them. That sky is more golden than you're going to get from photographs so we pushed that along.

Life Of Pi's Visual Effects Are Extraordinary. Here's Why

Ang gave us adjectives for how he wanted the sky to appear, if he wanted it to be "operatic" or "pensive" or "melancholy" and we would go to our sky library and find several for him that we thought might fit the bill.

From the stand point of cinematography on the blue screen set, we put up on a board what we thought the skies would be so that we would shoot the scenes with the appropriate amount of overcast quality and the light angles or the time of day correct so that the key light angle and sharpness of shadow would be appropriate. Any sort of colour quality or overall brightness could be fit to the sky afterwards.

And then Bill and I ran out of time.

Life of Pi is on release across the UK from Thursday December 20th and has been playing in US cinemas for some time. See it in 3D.