Why CG fire looks terrible even in high-budget movies

Originally published at: Why CG fire looks terrible even in high-budget movies | Boing Boing


Corridor Digital has gone into length over this issue in several videos but they cover something similar in this excellent one on explosions


The video clip looks “fine” to me - though probably because my standards of what an explosion should look like have been so degraded by video games, where even terrible looking explosions are a huge (and incredibly recent) improvement. (It’s kind of amazing how long the industry was able to use a particular stock-art fire/explosion CD ROM as it’s source of FX, ubiquitous in '90s games but still used well into the 3D graphics era, when other 2D images were added in for variety. It’s only been in recent years, when pre-baked and now real-time fluid dynamics have become feasible, that something substantially better was possible. The industry had gotten pretty good at hiding the fact that you were looking at 2D images, though.)

Still, Hollywood fire/explosions are really more conventions than anything - everything is so “sweetened” that it bears little resemblance to the real things, so one arbitrary, stylized convention is as good as another, really.


Came here to say this. I don’t even know what a real explosion should look like. I’ve only seen a helicopter crash and explode in movies. I doubt that anything I’m seeing is what it would look like in real life. The only question for me is: does this take me out of the movie experience?

And seeing the explosion in this clip a second time…yeah. All those explosive debris flying out and disappearing on the ground is pretty bad. But, really, when I see a movie like this, I already turn off the critical part of the brain and I barely notice.


… yes, people are so spoiled now

We can watch some monster movies from before 1980 if we really want to see bad special effects

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Pretty sure all explosions look exactly like a small coil of det cord going off behind a bag of gasoline, in slow-mo. Surely Hollywood wouldn’t lie to us?

And when a movie is a comedy, as this particular one was, explosions that I perceive as being slightly absurd, even subconsciously, are actually quite fitting. Come to think of it, Hollywood explosions are usually so ridiculous - over the top, physics-defying, and/or responding to what characters are doing in (perhaps unintentionally) comical ways that my response to something exploding on screen is usually laughter, if anything.

Yeah, those old bad movie FX are totally unrealistic - real explosions don’t look like miniature clouds of combusting powder in slo-mo, they look like larger clouds of combusting gasoline in slo-mo!


Isn’t that what technology is for?

Smbc Technological progress


The only bit that looked off was the single large fiery piece that landed on the roof top… almost like a last second addition; hokey looking when it landed, and the flames spread along it looked appropriate for a fireplace log.

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Porno for pyros, as it were.


I was laughing my head off when watching “Act of Valor”; which was sold on its technical realism. Every grenade appeared to go off right on top of a stash of terrorist petrol cans.


“What are all these suspended bags of gasoline doing on the battlefield?”

I’m okay with poor explosions, but I hate how poorly campfires (and small clumps of burning debris) are done. In real life, they smoke, they aren’t generally blue, and they often send out sparks here and there. It’s like none of these folks have ever been camping.

Real fire doesn’t photograph well on film. One frame of film has a uniform speed, so it relies on the overall scene having roughly similar intensity. But each part of the fire has its own brightness that almost never matches the rest of the lighting in the scene, so some parts will be too bright or too dark. And the various colors in the campfire flames don’t have the same intensity, so the blue may not be visible next to yellows or oranges.

To get a print of fire to look good takes darkroom work to reduce the exposure of the too bright areas, and increase the exposure of the dark areas. That’s hard enough for one frame, let alone repeating the process for 24 frames per second of movie film, and then making sure all those frames are evenly balanced with each other so the movie doesn’t flicker.

My favorite “bad fire” example of this was the old Conan The Barbarian movie from 1982, with Arnold as Conan. The scene is in an underground cavern, with a lit torch in a sconce on the wall next to a door. They had to add so much light to film the door that the flame from the torch was casting a shadow on the wall behind it!

Digital cameras have greatly improved on this, of course. They’re capable of exposing different areas of a scene differently, recording an image much closer to what the human eye is seeing. And that tech is now available in higher end phone cameras.

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