Alec Baldwin shooting has some people calling for computer-generated gunshots for film

Making computer generated gunshots is not as easy as it sounds

Alec Baldwin shot dead Halyna Hutchins on the set of his new film Rust (Getty Images)

Digital effects have helped Sandra Bullock hurtle through space, a sports car hurtle between skyscrapers and even Robert De Niro hurtle back to the age of 30.

But can it make a character fire a gun?

The question of whether digital effects could substitute for a gun firing on a TV or film set has been circulating in political and entertainment realms since the Alec Baldwin incident on Rust, in which the actor unknowingly discharged a live weapon that was handed to him, killing cinematographer Halyna Hutchins. Several creators vowed to stop using use live weapons on set, 60,000 people signed a petition supporting such a move and a California state senator said he would introduce a bill to ban the firearms.

But many directors have long preferred the sight of real guns firing, which they believe looks better and keeps viewers more invested in their story. The technology is now advancing to the point they’d have less reason to resist – but that’s hardly a certainty.

Traditional computer-generated (CG) images can achieve some but not all of the effect of a traditional firearm. One innovation, photogrammetry, can replicate the full effect of a real gun, but it’s a more involved procedure and costs money.

First, some explanation. A real-life gun shot can be broken down into three components: the recoil of the weapon; the muzzle flash (that burst of light from when hot high-pressure gas mixes with air as it exits the gun); and the impact when the projectile at the front of the cartridge hits.

Using a live weapon to shoot a blank (i.e., a cartridge without the projectile) is a time-honored Hollywood way to re-create a gunshot. Why not? It perfectly captures the first two parts of the process. The actor is pulling the trigger on a real gun, causing a recoil, and the real gun creates a real muzzle flash; the blank just means there’s no bullet at the tip. The third part is taken care of by squibs – micro-explosive charges distributed elsewhere – which are timed to detonate, releasing ketchupy makeup on a shirt or making a hole in a wall.

To innovate and try to do this without a live weapon means technology needs to step in.

The first part can be replicated with an air or BB gun that creates a similar if not exact recoil as a traditional gun. The last part, the squib, doesn’t require a live gun. The muzzle flash? That’s harder.

CG can actually create light that looks pretty good. And a gun shot is usually just one or two frames anyway.

But in real life a blinding flash doesn’t stay static on the gun – it bathes the whole room and everything in it in light. That’s where the problems start.

“We can make the flash pretty easily,” said Marc Côté, a veteran visual-effects supervisor who has worked on the HBO hit Big Little Lies, Apple TV Plus’s The Morning Show and the 2011 3-D epic adventure Immortals. “Making the light spread on characters and the setting is what’s tricky.”

In other words, a gun in CG can go off, but the light from it doesn’t go anywhere, just stops at the end of the barrel like one of those mini-flags in a clown gun.

This is where photogrammetry, an in-screen tool that converts images from two to three dimensions, can help. The tool is pretty new, and many effects houses don’t regularly use it. (The term generally refers to using photos to measure distances between objects, but filmmakers use it to mean creating depth out of that measurement process.)

A photogrammetric tool draws on photos to analyze the distances, then calculates the data it gathers to represent the images with actual depth – it makes stills look dynamic. Photogrammetry was employed for one of the first times in Hollywood on a harrowing midair scene in the 2008 James Bond movie Quantum of Solace, making it seem like Daniel Craig and Olga Kurlyenko were in free fall from a crashing plane when in fact they were standing in a wind tunnel in England.

Solfar Studios, a cutting-edge Icelandic studio, used it to create a virtual reality piece of Everest-climbing content without leaving Reykjavik. So do videogame designers.

Mr Côté deployed it on Big Little Lies so Nicole Kidman and Reese Witherspoon could seem to be at a café in Monterey, California, which they were nowhere near. The effects whiz and Montreal-based studio he founded, Real By Fake, ratcheted up their use of the tech during Covid lockdowns, when it became critical to get a real-life feel without people around.

Mr Côté said the tool can also be employed to depict a live gunshot. The still image of the flash at the end of the gun would be photogrammetried, as it were, to spread to the rest of the room, and even a savvy viewer would be none the wiser. It just would take a bunch of extra hours, since you’d be creating a new special effect each time, and spending as much as a few thousand dollars every time a gun was fired.

Some officials say the move to digital is worth it. “Those working behind the scenes to entertain and bring joy to millions all over the world shouldn’t go to set worrying if they will return home safely to their family,” said the California lawmaker, Democrat Dave Cortese, in announcing his bill.

Several Hollywood veterans have embraced the shift too. “There’s no reason to have guns loaded with blanks or anything on set anymore,” tweeted Mare of Easttown director Craig Zobel. “Should just be fully outlawed. There’s computers now. The gunshots on Mare of Easttown are all digital. You can probably tell, but who cares? It’s an unnecessary risk.” (Many of us could probably not tell.) Eric Kripke, showrunner on Amazon’s The Boys, offered a similar sentiment. (Amazon founder Jeff Bezos owns The Washington Post.)

Others went further. “As of today, it is now policy on ‘The Rookie’ that all gunfire on set will be Air Soft guns with CG muzzle flashes added in post,” said Alexi Hawley, showrunner on the ABC crime drama.

“There will be no more ‘live weapons’ on the show,” he added, noting that the safety of the synthetic was worth the sacrifice in realism.

Indeed, the issue at the heart of CG gunfire is the one that lies beneath much cutting-edge content innovation, from deepfakes to auto-tuning. It’s a question of whether technical reproductions can keep pace with physical reality - and the tradeoffs, ethically and qualitatively, in the attempt.

Of course, there’s a Catch-22 here: the productions with the least experienced staff to guard the guns, like the low-budget Rust, are also least likely to be able to afford pricey effects. Based on Mr Côté’s calculations, a production with numerous CG shootouts could add tens or even hundreds of thousand dollars in costs.

It may be a while before the tech gets cheaper. Until then, productions could go another way, like showing the gun from a distant angle, or in a dark room where the muzzle flash wouldn’t spread as much. Lacking technological means, Hollywood could try its most reliable innovation: the workaround.

The Washington Post