ILM’s Ben Snow Talks Pirates, Mermaids and 3D Pipeline
B.S.: Well, Pirates of the Caribbean: On Stranger Tides was a challenge because we had a short schedule and the studio really wanted to do the film in 3D. So, luckily we’d just had the experience of [doing] the Star Tours Ride, and on the chunk of shots that ILM did on Avatar, of setting up a stereo pipeline. It was actually pretty robust when we got into it. On parts of the Caribbean, we were using footage shot with RED cameras, which was the first time we’d used that at ILM. We were able to benefit from a really good relationship with RED where they were very cooperative with us, sent us up the camera. We did a bunch of color tests and evaluations, and looked at ways that we could make the RED footage look more like film. So we had a lot of help and encouragement on the technical side, and our team at ILM came up with some interesting ways to convert their data that I think helped the project.
We were dealing with the digital pipeline, we were dealing with the 3D pipeline. The issues for us were, you’ve got a bunch of mermaids splashing around in water. It’s really quite challenging to track in their splashes. So we ended up going with a lot more computer generated splashes. In addition, we went and filmed stereo splashes as well, separate, so that we would have that material to composite in. But, that was where the stereo actually got complicated. I have to say, one thing that really benefited us on the film, in terms of stereo, was that the decision was made early on, mostly at the suggestion of the stereographer and with our complete enthusiastic support, to shoot the project in as near parallel as we could, more like an animated film. Stereo films that have been made up till this point tend to use a rig which has a convergence where the camera actually angles in and focuses on something. The disadvantage of that [method] is that means you really have to decide where you want the convergence while you are making the film. Also, it has complicated things like match animation, match moving cameras and rotoscoping a little bit. So even though it [shooting parallel] didn’t make it easy shooting stereo, what we found was compared to other films we were doing in 3D at that time [at ILM], we actually ran into a lot of less headaches because of taking this parallel approach. What it meant was that you use the ability of the RED camera to shoot an oversized image. We crop that image and that’s how we have the flexibility to adjust conversions. We are throwing away a hundred pixels either side of the frame but it does give us the flexibility and it did seem to make it smoother in terms of the things that we thought would be hard on the stereo.
D.S.: Even with a pretty robust stereo pipeline, it sounds like working in 3D makes things much more complex.