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Physics Works

The Physics Works series highlights the application of physics Physics Works series highlights the application of physics Physics Worksin varied, and sometimes unexpected, industries. Physics is central to the economies of the UK and Ireland. Whether through the application of novel research and technologies, or through the skills and abilities of physics-trained workers, physics is at the heart of business and innovation, paving the way for economic growth.

From lasers to graphene, products of physics research are now being used in corporate labs around the world and can be seen in all areas of industry.

The Institute of Physics is a leading scientifi c society. We are a charitable organisation with a worldwide membership of more than 50,000, working together to advance physics education, research and application. We engage with policymakers and the general public to develop awareness and understanding of the value of physics and, through IOP Publishing, we are world leaders in professional scientifi c communications.

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32 Physics WoWoW rks VFX

Introduction

Once, visual effects (VFX) in fi lms were relatively simple affairs. Matte paintings placed in the background of a scene to make it look like somewhere else. Alien monsters that were really men in makeup. Miniature models of vehicles or creatures captured on fi lm for a single frame, repositioned, and shot again, over and over.

Now, the cameras are digital – and so are many of the effects. Much more realistic-looking effects can be produced, with the aid of computers, to satisfy increasingly demanding modern audiences. And doing so involves a lot of physics.

Production

In the past, the creation of visual effects would take place predominantly in post-production. Now, however, because complex effects require so much more planning, VFX producers are involved much earlier in the process.

Typically this will involve meeting a director to understand their needs, and storyboarding their vision. It increasingly involves digital pre-visualisation – a computer-generated preview of a production setup, such as how the lighting will work and how the camera will move when shooting a scene. It requires implicit knowledge of physics in, for example, the technical capabilities of the rig, or of optics in order to light a scene correctly. Live action is fi lmed using parameters determined by that pre-visualisation, and then the scene edited digitally, including matching with any purely computer-generated additions.

Tooned in progress, image courtesy of McLaren and Framestore

54 Physics WoWoW rks VFX

The real-world physics of, for example, fl uids, particle collisions, light refl ections to be reproduced in computer simulations

Robotics to control cameras, and the articulation of camera rigs’ joints

Tracking the movement of camera in 3D, and matching those movements with computer-generated renderings of scenes

The technical knowledge of how rigs work, how to control their motion with speed and precision, and what’s technically and physically possible to get out of them

Knowledge of trigonometry, parallax and focus to set up a shot in 3D

Physics

Almost a quarter of those employed in the UK’s visual effects industry have a degree in one of the natural sciences, maths, engineering, or computer science. VFX company Double Negative goes so far as to employ a chief scientist, refl ecting their recognition of how important it is to get the physics right.

It’s inherent to many and varied aspects of the fi lm-production process, from the science of photography, through the technology used to carry out shoots and generate effects, to the knowledge of the real-life behaviour of things to be reproduced as computer-generated imagery.

Film and physics feedback upon one another too. Sometimes the desire to produce a particular effect drives the development of the technology to make it possible. More often, a new piece of technology becomes available and VFX companies will fi nd an innovative use for it.

A simulation of a black hole produced by Double Negative for the science fi ction fi lm Interstellar, directed by Christopher Interstellar, directed by Christopher InterstellarNolan, even led to insights into real astrophysics.

Physics in fi lmThe use of, or knowledge in, physics is commonplace in fi lm production, such as:

76 Physics WoWoW rks VFX

VFX contributes £1.6 bn annually to the UK economy

£1.6annually to the UK economy

1.6annually to the UK economy

bn

Economy

Film production in the UK is big business. In 2011 the industry supported almost 44,000 jobs and directly contributed £1.6 bn to the country’s gross domestic product – more than electronics manufacture or software publishing. When other economic activity supported by the fi lm industry is included, those fi gures swell to £4.6 bn of GDP and more than 115,000 jobs.

VFX is one of the fastest-growing creative industries. In the UK, between 2006 and 2008 alone the sector grew by around 17 %.

Guardians of the Galaxy, images courtesy of Marvel and FramestoreGuardians of the Galaxy, images courtesy of Marvel and FramestoreGuardians of the Galaxy

Knowledge of real-world

98 Physics WoWoW rks VFX

Knowledge of real-world physics informs a lot of decisions about how things look

BlueBolt (London)

For BlueBolt – whose fi lm and TV credits include Game of Thrones and the latest instalment of the James Bond of Thrones and the latest instalment of the James Bond of Thronesfranchise, Skyfall – knowledge of real-world physics informs Skyfall – knowledge of real-world physics informs Skyfalla lot of decisions about how things look.

Making visual effects look real relies on careful matching between a camera shot and what they’re inserting into that shot – such as shadows and refl ections. When simulating a camera and lens to create elements to add to an existing shot, the company needs to know the mechanical limitations of how a real camera could move, and what imperfections might be introduced, such as lens fl are, retaining them in the fi nal shot to maintain a realistic look.

If BlueBolt fi nds itself having to comply with a director’s request to make something more prominent in a particular shot, this can be achieved through its composition or lighting, with animation, or sometimes by compromising with how something would be in reality – and knowing the limits of such compromises is essential to maintaining believability.

Effects such as smoke and fi re sometimes require simulation of how particles really behave, which is done with software with a lot of parameters that can be tweaked to achieve the desired look. Although this is incredibly time-intensive, it’s necessary when there is a complicated camera movement or a lot of interaction with other objects in the scene, precluding the use of real elements.

Game of Thrones, image courtesy of HBO, Henry Badgett – BlueBolt VFX supervisor

goes so far as to employ a chief scientist

Navier-Stokes equations

1110 Physics WoWoW rks VFX

VFX company Double Negative goes so far as to employ a chief scientist

Accurately portraying the behaviour of mixing fl uids meant programming their effects software with the Navier-Stokes equations

Double Negative (London)

Double Negative’s chief scientist, Oliver James, comes from a physics background, and the company, which has around 60 people working in R&D and around 700 artists, makes extensive use of simulations to ensure their effects look realistic – even for fi lms set in a world that is not.

An effect for the Harry Potter series involved modelling the Harry Potter series involved modelling the Harry Potterbehaviour of a “pensieve” – a device in the magical universe that allows its wizards to view memories, which looks like a basin fi lled with fl uid. Accurately portraying the behaviour of mixing fl uids meant programming their effects software with the Navier-Stokes equations.

But their expertise is in no way limited to abstract matter or to pieces of technology. In The Bourne Ultimatum in 2007, a scene in which the titular character, played by Matt Damon, is 10 years younger was achieved by using motion capture – a technique more commonly associated with more fantastical creatures like The Lord of the Rings’ Gollum – to map Damon’s The Lord of the Rings’ Gollum – to map Damon’s The Lord of the Rings’movements onto a digital scan of the actor taken previously. The company believes this technique will become increasingly common in the future.

Most recently, in the science fi ction fi lm Interstellar, the Interstellar, the Interstellargravitational warping of light around a black hole was modelled in a collaboration with Caltech general relativity expert Prof. Kip Thorne. The resulting effect – a glowing accretion disc folded into two perpendicular glowing rings – surprised even Thorne, who had never imagined his equations could create such spectacular images.

1312 Physics WoWoW rks VFX

Understanding fracture dynamics makes explosions realistic

Edge of Tomorrow, image courtesy of Warner Bros. and Framestore

Harry Potter and the Deathly Hallows: Part 1, image courtesy of Warner Bros. and Framestore

Framestore are driven to make their effects look far more realistic. To do this it is necessary to understand the physics behind the effects they are creating

with surfaces

1716 Physics WoWoW rks VFX

Framestore simulate how light behaves when it interacts with surfaces

Framestore (London)

Framestore are one of the visual effects companies behind the 2013 science fi ction fi lm Gravity, which starred George Gravity, which starred George GravityClooney and Sandra Bullock. They spent three years working on material for the fi lm, which won the Academy Award for Best Visual Effects in 2014.

Recognising that modern audiences are increasingly discerning, they strive to make their visual effects as realistic as possible. This means having to understand and apply everything from basic Newtonian mechanics – to make sure things fall or collide believably – to fracture dynamics for destruction effects such as explosions.

When working on Gravity, Framestore studied every available Gravity, Framestore studied every available Gravitybit of space footage from NASA to get a handle on how things look and move. The fi nal effects were rendered with a photorealistic “ray tracer”, which simulates exactly how light behaves when it interacts with real surfaces.

Framestore tries to get hold of physical pieces of any material that they have to recreate in their visual effects, so they can study how it looks and behaves. The company says that understanding the physics behind the way things work helps them to create effects that look much more consistent and realistic.

Gravity, image courtesy of Warner Bros. and FramestoreGravity, image courtesy of Warner Bros. and FramestoreGravity

meet, and fi nd motivation in innovation

Each separate

1918 Physics WoWoW rks VFX

The visual effects industry is one where art and science meet, and fi nd motivation in innovation

Each separate component involves a physics-based

in innovation

Each separate

simulation

One of Us (London)

When working on Under the Skin in 2013, One of Us built a system allowing them to use eight cameras to fi lm Scarlett Johansson driving around Scotland. The company has also built a 40-camera rig, and the software to navigate resultant footage. They see the visual effects industry as one where art and science meet, and fi nd motivation in innovation.

Their work is based on manipulating digital camera images and combining them with others, and sometimes with computer-generated imagery. Getting the various elements right is partly subjective judgement, but partly based on objective, measureable factors.

They might, for example, fi lm a shot of a seascape and create a computer-generated submarine surfacing. In this case, the company would need to understand the principles of optics and the refl ectivity of different surfaces to get the lighting right, and uses a fl uid simulation system to accurately portray the splash, foam and eddying created as the submarine emerges from beneath the waves.

Such simulations are a regular component of what One of Us does – especially where there are complex interactions between objects. Wherever something they’ve worked on depicts, say, a building collapsing, rubble crashing to the ground, curtains fl apping or a cloud of dust rising, each separate component involves a physics-based simulation.

Although they sometimes ignore the laws of physics if it works better for a particular shot, they say it helps to know which rules they’re breaking.

20 Physics WoWoW rks

Impact

Physics is at the heart of a wide range of industries, including visual effects. Therefore an understanding of physics, from how objects interact and making an explosion look realistic to how to use robots on a shoot, is advantageous in the VFX business.

You can apply physics and engineering know-how to work at fi rms such as those included in Physics Works. Our scientifi c careers service brightrecruits.com is a world-leading jobsite for the physical sciences and engineering communities. We assist academia, research and industry in their search to fi nd the brightest minds, for a variety of different roles. With more than 70 titles in the IOP Publishing portfolio, including the fl agship publication Physics World, the reach of brightrecruits.comis unrivalled.

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