Catastrophe is something the vfx wizards need to know for Knowing. All images © Summit Ent.

Director Alex Proyas has a strong track record of pushing the envelope with visual effects. From the shape-shifting buildings of Dark City to I, Robot's photorealistic robots, his movies feature unique ambiances and striking imagery. Opening today from Summit Ent., Knowing, his latest film, definitely follows this tradition as some 400 visual effects shots recreate various disasters with an unprecedented level of detail. The catastrophes range from local tragedies -- plane crash, subway collision -- to global phenomenon.

In order to create those large-scale disasters -- and many other vfx, Proyas turned to Sydney-based Animal Logic and Overall Visual Effects Supervisor Andrew Jackson. The initial vfx shot count was around 200, with seven months of postproduction. Jackson and VFX Producers Michael Twigg and Luke Hetherington assembled a team that included 3D Supervisors Alfie Olivier, Andreas Wanda and Will Reichelt, and Compositing Supervisors Charlie Armstrong and Dave Dally.

Although the script called for some very spectacular imagery, Proyas wanted the entire movie to have a strong realistic feel. "It should all feel like someone with a camera had been there, on location, when the events took place," Jackson observes.

"It meant that we couldn't do anything that a real person manning a real camera couldn't have done in each particular location. Alex didn't want any fancy 3D camera move. The shots were all hand-held, and had to feel like the cameraman was trying to follow the action the best he could, just like in news footage. Even for the space shots, Alex requested that it all looked like the footage had been captured by a human cameraman."

According to Jackson, the team benefited from the fact that the movie was shot using the new RED digital camera. "On set, one of the advantages is that you can just keep on shooting, and not worry about the quantity of film stock that you are using. Then, in post, you can access absolutely everything that was shot -- and that is a huge benefit for us. When the plates are shot in 35mm, you just cannot have everything scanned. You need to choose the plates that you need, and then justify the cost of having the scans done. That not being an issue in digital, it is absolutely fantastic! You have every single take and outtake available. Plus, they are all time-coded. So, as long as the data management is good, you can get straight to any particular piece of footage."

On-set practical effects had to be combined with digital simulations for the plane crash. Images courtesy of Animal Logic. 

Crashing a CG Plane
All the key effects sequences were extensively previsualized, including the crucial plane crash sequence. Proyas designed an elaborate shot in which a 747 jumbo jet is seen crashing across a freeway and into a field before the main character rushes to the crash site, all in one shot. "This shot was definitely a challenge," Jackson recalls. "There were 3,196 frames... When we got the plates, we first had to paint out the huge rain towers that were on location. Then, we rebuilt the scenery in the computer. Alex wanted to be able to modify the movement of the plane in post. To this purpose, we had shot a very slow pan that followed the path of the CG plane. We could then reconstruct the location digitally by using different techniques. The background was a matte painting, the major part of the scene was a combination of separate tiles that were shot on location. The 3D card technique allowed us to pan through them with the 3D camera. When the scene was recreated, we could precisely adjust the camera to the motion of the plane that was finally approved.

"Right after the plane has crashed, there is a whip pan back to the road where we switch to the live-action footage with Nicolas Cage. Then, the camera follows him on the crash site, which was a whole different set-up. The art department built a very detailed set with lots of debris, large airplane elements, practical fire and smoke. We augmented it with CG explosions, and practical smoke and fire elements. We also extended the length of the shot by panning over to another part of the crash site, and then pan back to Nicolas Cage and go on with the original shot -- this added part was never filmed; we created it in CG."