HOW TO BUILD A FAKE OCEAN

THE MEG

THE PLOT

A prehistoric monster shark called a megalodon, thought to be extinct, attacks a research vessel. Then everyone else. Jason Statham has to kill it and save the world.

THE SCENE

Nearly all of them.

WE PLANNED TO shoot a fair amount of underwater live-action sequences in the ocean near New Zealand. We did our research and picked a time of year when the water was always clear. Of course the water wasn’t clear, and the two weeks we planned for shooting in the ocean were compressed into one day. So we built our own ocean.

We built two water tanks. One was for surface scenes. It was shallow, with depths of up to three metres and built like a trapezoid. One end was built like an infinity pool, so CGI could be used to extend the water. A trench in the middle can be rigged up with equipment for stunts – like for, say, a scene in which a boat gets overturned by an enormous shark. The other tank was 57 metres around and five metres deep. We used it for the underwater scenes. Unlike in the ocean, where you have to figure out how to light and shoot at depth, in a tank you can control the conditions. The real limitation is that you can’t pull back to a wide shot in a tank. But since you’re already using CGI to mask the tank itself, you can set the scene exactly as you want it. The tanks took 12 weeks to build.

The tank used for surface scenes was 40 m wide and one to 3 metres deep.

A trench in the middle of the tank provided room for equipment for stunts.