Film Doctor – What are SFX and VFX? – with the team from GRAVITY

Hi Film Folk,

With the UK release of Alfonso Cuarón‘s 3D IMAX heavyweight GRAVITY, the Film Doctor team are going to focus on two subjects integral to this film’s attraction – SFX and VFX.

And who better to talk about those subjects than the men who did them!! That’s right, today you’ll be reading the words of GRAVITY‘s SFX supervisor Neil Corbould and VFX supervisor Tim Webber from their recent BAFTA talks.

Read on!

Film Doctor - GRAVITY

SFX – with Gravity’s Neil Corbould

Neil got into SFX through his uncle (who worked on the Battle of Britain) and has himself worked on such films as Gladiator, The Day After Tomorrow and The Fifth Element.


What is the difference between SFX and VFX?

“VFX is computerised. SFX is in-camera and includes hydraulics, pyro etc.

SFX isn’t just whizz-bang stuff (which is what we’re known for), we do atmospherics too, which is essential for a film. So we do smog, mist, smoke, snow. Mist is hardest as you can’t control wind. Mother nature is hard to play with and a director sometimes want the wind blowing the other way!”


How is your interaction with the VFX department?

“We break the script down and budget (and producer’s never like the answers). We divide what VFX will do and we will do.

Often it can work practically and you can save a lot of CG but people don’t realise you can do it.Why do some filmmakers rely on VFX instead of SFX? For us to do stuff it does take longer and they don’t want to wait..but you get director’s like Spielberg and Nolan and they will wait.

I respect VFX a lot. We co-habit. We do things they can’t do realistically. A VFX supervisor said to me 30 years ago “I don’t know why you’re going into SFX. It’ll be dead in 10 years.” Clearly not.”


Test, test, test

“The key for us is testing absolutely everything. We test explosions from 100m away and then 80, then 60. For Saving Private Ryan we had 25k of dynamite 10ft away from Tom Hanks. We tested it several times beforehand with me in Tom’s position. We show the actors our tests, it puts them at ease.

We shoot bullets into helmets on rifle ranges. We do different combinations of blood, pete and dust to find the correct look. I have hundreds of hours of footage of bullets. The look of a different calibre gun will change the impact hit.”

Film Doctor - Gravity

VFX – with Gravity’s Tim Webber

Tim has been working at Framestore for nearly 3 decades and has worked on such films as The Dark Knight, Children of Men, Avatar and Where the Wild Things Are.

How is your interaction with the SFX department?

“There’s a huge grey area between every department. The best of everything is a combo of VFX and SFX. Usually if you just do one, you can see the technique.

VFX need the raw materials to work off of.”

How was working on Gravity?

 “Alfonso’s long shots made it impossible to go the traditional VFX route. We said let’s do it mostly CG, film their faces, make the rest CG – he said ‘don’t be ridiculous’ but it worked.”

“There was a huge closeness between cinematography and VFX. There has never been so much of an exchange of ideas as in Gravity.  Light is what makes an image beautiful or not beautiful. We lit the way a cinematographer would light. We used a renderer called Arnold. To rely on something as new as that was a risk and scary.”

“When we were building, we were building without the object there. You’ve got to light the character/object that isn’t there. That’s tricky.”

“Gravity wasn’t shot in 3D with 2 cameras but the VFX was built in 3D.”

Where are all the groundbreaking VFX taking place? Commercials? Music Videos? Films? 

“Groundbreaking VFX happens in films, the budgets are bigger and they use more in each shot and have more shots.”

What are the limitations of VFX? 

“Anything is possible in VFX. It’s just the time and the money that make things difficult – and there’s never enough time and never enough money!”

 How has VFX evolved?

“In the old days, the directors just left it to post. Now they all know the process. It’s not unexpected. It was the newness that made it a barrier. As a VFX supervisor today, you’re there from beginning to end.”

What are the keys to great VFX?

 “1. Your best work goes totally unnoticed which is how it should be (audience shouldn’t realise it’s not real).

2. You need to know when to skip one part so you have resources for other parts.  Making stuff better is easy. Knowing when it’s good enough is the hard decision.

3. The most important thing is understanding storytelling, not just VFX. How does it sit in the shot or the story. That’s the key.”

MONDAY PRESCRIPTION SFX/VFX SPECIAL – in Neil Corbould’s words “SFX, Animatronics and VFX are all tools. Use the ones needed for the job. They’re all in a toolbox, there isn’t one for everything.”

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Any questions/thoughts/experiences of your own??? Leave a comment below!
Have a great week!

The Film Doctor Team


Check out our previous INTERVIEWS and CASE STUDIES.

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