Out in the UK today, Ang Lee's adaptation of Yann Mantel's bestseller, Life of Pi, is probably the best use of stereoscopic 3D in 2012. While much has been made of the incredibly realistic CG animals created by Rhythm & Hues - including a tiger called Richard Parker who is in most of the film - two key sequences featured innovative VFX from London-based MPC.
Both feature storms - one sinking the cargo ship The Tsimtsum with Pi on board, leaving him stranded on a lifeboat with the aforementioned tiger, and the 'Storm of God' at the film's climax.
Realistic oceans rely on intense fluid simulations, which traditionally require massive computational power - especially when you're working in stereo 3D - and use physics engines that limit the amount of control VFX supervisors and directors can exert on them. However, Ang wanted to have the same control over the storms as he had over the actors.
"Ang told us from the get go, 'the ocean is a character like Richard Parker is a character, or like Pi is a character'," says MPC's VFX supervisor on the film, Guillaume Rocheron.
To give Ang the control he wanted, MPC worked with Scanline - creator of the Flowline fluid simulation software - to create a new simulation method that reduced rendering time and allowed more control. The 'refined sheet' method treated the surface of the ocean as a flat sheet that was deformed and animated by hand.
On top of this was poured a few metres deep of voxels, which were used to simulate the flow of water. The fluid simulation was applied to this, so this was rendering only a fraction of the full depth. The mix of control and allowed Ang and Guillaume to art direct each scene as they wished, with results that stand up to the lengthy shots - up to one minute - the director wanted to use to immerse the audience in each stereo 3D scene.
"That's why the shipwreck sequence [stills below] is a great piece of filmmaking," says Guillaume. "During [storm] sequences you usually have very fast cuts, and lots of flashes and lightning as you want it to be very exciting, scary and dramatic. Ang approached it very differently: you see everything. You have time to see the ship sinking, and Pi in the middle of the ocean - which makes it even more dramatic."
The control that they had enabled Guillaume to tone the two sequences differently. While the shipwreck scene is tense, the 'Storm of God' (top and below) needed to reflect Pi giving in to the power of nature and accepting its chaos.
MPC's tools allowed them to art direct a look of monumental awe instead of terrifying darkness. Guillaume says "it wasn't about the drama but instead it's the peak of Pi's journey. He's spent all these days on the lifeboat and we had to amp up everything to show that he's basically losing it."