Movie magic

From 007 or Harry Potter, physical and digital effects are playing a bigger, more sophisticated role in the creation of blockbuster films – and keeping audiences on the edge of their seats.

Special effects are now so sophisticated they are often as interesting as the films they make spectacular. Children flying on broomsticks, dinosaurs lurching into camera, cars flipping literally on thin ice – the effects fit so seamlessly into the action that no audience has an inkling of the expertise and time that go into creating them.

But big effects are part and parcel of big-budget film-making, as seen in this autumn’s imminent top box-office releases Lord of the Rings: the TwoTowers, Harry Potter and the Chamber of Secrets and the new James Bond film Die Another Day.

Effects can be split into two camps: physical and digital. Computers generate digital effects, creating Jurassic Park’s dinosaurs and the fighting cyborg robots of Terminator 2: Judgment Day.

Physical effects are the explosions, stunt rigs, models, robots and prosthetics that are very real and can easily go wrong on set.

Of these the animatronic models can be the most complex. They entail the movement of a mechanical device that is supposed to represent a living thing, whether a dinosaur or a baby. Buckinghamshire-based physical effects firm Millennium Effects specialises in this type of effect.

Owner and special make-up effects designer Neill Gorton says: ‘Everything we build is a prototype, we’re sort of winging it. We use stuff from everywhere, all off-the-shelf equipment. For example, the electronics for voice and lip synchronisation was originally designed for rock concert light rigs.’

Whether it is Star Wars’ Yoda or a T-Rex from Jurassic Park, effects technicians may want to control their puppets directly using a cable or a rod, or remotely, using radio. The radio signals often send instructions to brushless electric servo motors for movement. Model builders like to use hydraulics rather than pneumatics for more power and the more flowing movement that can be attained.

For a Jurassic Park monster such as a full-sized stegosaurus only big hydraulics will work, and these, says Gorton, came from amusement park development. While these great beasts may appear heavy, creatures are increasingly made from glass fibre or carbon fibre to keep the weight down.

Keith London, manager of Industrial Light & Magic’s model and creature shop, also emphasises the need to keep model mass low. Based in California, ILM creates all the effects for the Star Wars films, and London finds that size is an issue for his modellers. Cost control means small equals cheap, but there are limits to how small the models can be if they are to appear realistic. London says that when water or fire is involved the models have to be quarter scale. ‘We often build sets that are 60ft x 80ft, and we may have to make a boat that has to be blown up,’ he says.

Another area where scale was important for London’s team was the final battle arena in Star Wars Episode Two: Attack of the Clones. Matching the creatures with the sets created for the actors and the arena models was a challenge that was overcome with computer graphics.

For the real heavy-duty physical effects without computer aid industry insiders point to the James Bond films. Chris Corbould, a freelance special effects supervisor, works from Pinewood Studios and has been responsible for the films’ many death-defying gadgets.

In Die Another Day he was asked to modify four Aston Martin V12 Vanquishes and four Jaguar XKR convertibles so they could duel, with machine guns and rockets, at speeds of up to 90mph across a frozen lake. ‘The biggest challenge was the timescale, as we adapted the cars over approximately four months, from start to finish,’ he says. To drive at the required speeds across ice they had to be changed to four-wheel drive and have enough room inside for all the gadgets.

Corbould says: ‘The team fitted a transfer box, different front axles and differentials, installed a 5-litre Ford SVO engine and totally moved around the whole front end. The R&D involved was pretty immense for the 20-strong team which put in lots of CAD work and worked long hours.’

As well as vehicle stability on the ice, which also required special studded tyres, the team had to contend with severe temperatures of around -20 degrees C.

Corbould explains that because of the extreme cold all the engine management was deliberately kept very basic.

In one scene both cars get drenched – another reason he chose not to use complicated engine electronics. But that wasn’t Corbould’s biggest fear. ‘In each car we fitted buoyancy bags so that if one went through the ice the car would stay afloat.’

While the cars were rugged mechanical beasts, more complicated electrics were used on the gadgets inside them. ‘Bond’s Aston Martin features motion-sensing pop-up shotguns coming out of the bonnet and rockets, while the villain Zao’s Jag has mortars coming out of the back and a manually aimed Gatling gun. All this used pneumatics, computer-controlled electronics and some propane flame effects,’ says Corbould.

But the most dramatic stunt on the ice lake duel is the car flip. Bond’s car is blown on to its roof by a missile explosion and 007 rights his Vanquish using the ejector seat.

Corbould explains: ‘It’s basically flipped back over by a nitrogen cannon built into the seat. It’s a nitrogen piston, and if you fired it the right way up it would probably send the chair about 80ft in the air.’

Seven years ago when the digital revolution in films began Corbould thought his team would last only another three or four years. Fortunately for them it didn’t quite work out that way. On this Bond film there were 110 effects technicians compared with 80 on the last, and 60 on the one before that. Corbould says: ‘Because now they can attempt films they couldn’t before, it’s knocked over on to us and our workload has gone up.’

However, the role of computers cannot be underestimated. Whereas historically the high-powered image-processing machines have made the impossible real during post-production, today digital effects are being used in pre-production and during actual filming.

Davie Johnston, technical operations manager at digital effects firm The Moving Picture Company (TMPC), says that a fairly recent change – thanks to the processing power of laptops – is to have people working on pre-visualisation on the set of a feature film as it is being shot. He says: ‘They can take feed off the camera and do rough shots to show the director how it’s going to work in context. With some of the films you can use virtual set technology to allow the director to see the 3D background you are building.’

The laptops use downgraded versions of the in-house software. At a digital effects firm the technology, for both 2D and 3D effects, is far more powerful than any laptop could handle. For film projects TMPC uses workstations with linux operating systems and 2.4GHz or 3.6GHz processors to manipulate data on each effect shot.

Johnston explains how digital effects people approach shots. ‘We break a film down into scenes within the movie, shots within the scenes, and finally frames within the shot. When people say ‘effects shot’, it tends to be a sequence such as a dragon attack. A shot can be anything from four seconds to five minutes.’

When all the shots are added up these companies face major data-handling issues. An hour of movie data is about a terabyte. So TMPC has all its dual-processor workstations connected to a local area network. This in turn is linked to around 400 2GHz processors, each with a speed of a teraflop.

The US Department of Defence only needs machines as fast as 12-13 teraflops to simulate actual nuclear weapons for their development. And some of the machines TMPC uses, for example the Apple Macintosh G4, are so powerful the US government restricts their export.

Few cinemagoers realise the amount of computer power needed to provide children and adults alike with that fantastic journey, or that it often only represents a fraction of the actual film. Harry Potter and the Chamber of Secrets took 15 months to shoot with 50 special effects people and 249 shots, Johnston says – all of which ended up as about 15 minutes of the film.

‘We did two main elements in the film: one was Ford Anglia that took Harry Potter to Hogwarts, the other was replacing the actors inside the car. for that we did a full laser scan of the actors,’ says Johnston.

Once all the image manipulationis done inside the computer the finished product has to be put back on celluloid. A machine called an Arri laser is used to burn in one frame in around three seconds; three years ago it was about 45 seconds and it will soon be 1.7 seconds.

At that speed if every frame in a two-hour film had to be digitally enhanced, which at 24 frames per second is 172,800 frames, the whole thing could be burnt on to celluloid in 81 hours.

Faster turnaround with literally bigger bangs for fewer bucks adds up to a special effects ‘arms’ race that will not stop. The ferocious competitiveness of the film industry will ensure that special effects technological development is never short of cash and audiences will continue to witness the impossible.