The prevailing belief among Hollywood producers and casual film fans is that practical effects, while cool and fun in the "we like old-timey moviemaking" sense, just aren't as versatile as CGI. Prosthetics and puppets look good in close-ups, but when you need them to move dynamically or crash mightily through a building, there's no competing with what computer effects can do. You can create entire worlds with freaking green screens (see Avatar, The Hobbit, George Lucas' fever dreams, etc.). Meanwhile, practical effects got left in the dust back when Jurassic Park came out and proved we didn't need them anymore.

The truth is that practical effects have been steadily improving over the past 20 years, just like digital effects -- they just don't get used. The kinds of prosthetics and monster costumes being made today are so advanced, audiences from 1993 would probably have mistaken them for CGI and/or witchcraft. The problem is, Hollywood has spent the past two decades forgetting what it was like when you couldn't just go back in post-production and add giant dewback lizards to whatever scene you wanted. Practical effects aren't sexy anymore, and that mentality is hurting the development of the art that movies used to depend so much on. For example, check all the awesome s**t Gillis and Woodruff made for 2011's prequel to The Thing:

studioADI
They look great moving, too. Check out the footage.

Gillis and Woodruff refer to their work on that movie as "every creature effects worker's dream", because John Carpenter's original The Thing was such a legendary achievement in the field of Practical Effects That Made Audiences s**t Their Pants. They were beyond excited for the opportunity to design a new batch of shapeshifting, alien horror beasts for the follow-up film -- that is, until every single creature they designed was replaced with CGI in post-production.

Universal Studios
Much better!

That's right -- the hundreds of hours of work they put in to sculpting, painting, and performing their monsters was all painted over with digital effects, because the producers felt their gruesome handiwork "looked a bit like an 80s movie." Truly, when making a follow-up to a 30-year-old horror movie with a devoted cult following, the last thing you want to do is remind people of the original.

But all of that is just a reminder ...

Woodruff and Gillis worked on the later Aliens films, but before that, they created the monsters for Tremors, which is a film about demon slug beasts that live underground and occasionally burst up through the dirt to eat Kevin Bacon. Unlike their work on the Alien movies, where they had a pre-existing design to work with, they had to come up with Tremors' monsters entirely from scratch. So they combined the basic look of a worm (for obvious reasons) with something that looked like it would live in the desert, because that's where the movie takes place. The end result was this sandy behemoth:

Robert Christopher Sargent
Admittedly, it looks a bit less scary hanging on an office wall in Los Angeles.

"The director wanted them to be naturalistic looking ... to look like they could exist," says Gillis. "Maybe they're prehistoric, maybe not. ... When you live a lifetime being fascinated with monsters, wildlife, and creatures -- doing as much research as possible -- you're already in a place where you know [what] the target range of look and textures might be in a desert. I can say, OK, it's gotta move through the ground rapidly like a shark moves through water. But earth has more resistance than water, so rather than worming its way through, it muscles its way through."

Then, of course, they had to build it:

There are plenty of ways that process can go wrong, but ultimately the only test was asking the question, "Does this thing look cool, and does it look like something that could plausibly swim through dirt and eat Fred Ward?" But when you're making creatures for an Alien spinoff, well, things can get a little more complicated.

Woodruff and Gillis have worked on the Alien franchise since part 3 -- in fact, Tom actually is the alien in Alien 3; he's wearing the costume in most of the shots:

20th Century Fox
Under the mask, he'd make the same face after realizing how long it would take to remove the suit to go pee.

Years later ADI (Woodruff and Gillis' studio) got the opportunity to design an Alien/Predator hybrid when they worked on Alien vs. Predator: Requiem. Once again, it was an effects artist's dream come true -- a chance to combine two of the most iconic monsters in movie history and create something new. You can almost feel them geeking out when you look at some of their early designs:

studioADI
"And then all four combine to make a giant-super Predalien, and then ..."

However, when they submitted their final design to the studio, the producers decided to ask a random 14-year-old kid who happened to be in the building that day what he thought of the design, because Hollywood is the only place in the universe that gives a s**t what 14-year-old boys think. The kid's response was, "Cool alien," which threw the producers into a panic -- clearly this meant that Woodruff and Gillis' design didn't have enough Predator in it (it should be noted that Predator, being a creature from space, is also an alien, so the kid might've just been speaking literally). So they sent Gillis and Woodruff back to the drawing board.

20th Century Fox
Maybe try leaving the voting to people old enough to do it legally.

Practical effects are an insanely precise and complicated art -- a creature is designed not only for how it looks, but how it's going to be lit, how it's going to be shot, what kinds of effects work best for the scenes in which it is going to appear, and so on. There's a mountain of thought and experience that goes into every decision, no matter how minor. But when a franchise gets bigger, there are more and more layers of opinions standing between each stage of the process.

"When you get to 2, 3, 4 chapters of a story [Alien vs. Predator: Requiem was the sixth Alien movie and the fourth Predator movie], so many people are brought in to make decisions. It's not just us and the director," Woodruff says. "Sometimes they have good ideas, but they didn't spend their lives loving monsters and making monsters and breathing monsters."

These are, of course, the kind of decisions that can't be made lightly if you're going to work with a physical alien costume (or puppet, or model). When everything exists in a computer, changes to the design can be made on the fly. And that's not always a good thing ...

CGI doesn't have to look fake -- Woodruff and Gillis made it clear there are some fantastic CGI effects out there. Hell, a lot of the digital effects you've seen, you didn't even know they were effects at all -- like the digital Atlantic City used in Boardwalk Empire:

But they do create a shortcut that changes how movies are made -- specifically, that there is less of a connection between the effects and the actual shoot. In the days when practical effects were pretty much the only option, everything had to work properly on set the day of filming, or else there was no movie and everyone went home unemployed. Nowadays, since everything is done with computers, it doesn't matter what the hell happens on the day of the shoot -- the director assumes you can always go back later and correct it with digital effects. But if the original footage isn't a good match, there's no way to make the CGI look right (see the clumsy attempt to add digital creatures to the Star Wars special editions).

For an example, let's again compare The Thing (1982) versus The Thing (2011): the John Carpenter original relied completely on practical monster effects, and those effects only looked good from certain angles, so each shot had to be meticulously planned out. For instance, this fantastically creepy shot involving a severed head which has sprouted eye stalks and offal-coated spider legs ...

Universal Studios
Perfectly composed to show both the horror of the monster and the magnificence of Kurt Russel's hair.

... probably looks f*****g ridiculous from any other angle. The shot had to be precisely planned out beforehand, and the spider head was designed with that exact shot in mind. It's a standard filmmaking technique -- if the audience can only see two sides of a building, it doesn't matter what the rest of the building looks like. And that's all assuming that the spider actually worked the way it was supposed to. If two of its legs fell off or it tipped over and caught fire once the cameras started rolling, production would either have to shut down for the day or move on to a different scene while the effects guys repaired it.

However, now that you can just insert whatever you need in a particular shot with CGI, the idea of careful preplanning has more or less gone out the window. "In the prequel to The Thing we have a character who's splitting open," Woodruff explains, "and then he stands and erupts. We had this idea to do most of it in-camera [without digital effects]. I put all this crap on, and if I turned sideways, you could see my head, but from the front [you couldn't] -- it's like a stage illusion. I remember we tested it on camera, and it looked great!"

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"Great" here meaning "like the gaping maw of hell itself".

But when Woodruff and Gillis showed it off, the producers weren't happy. They kept pointing out that the prosthetic only worked when you looked at it from a specific angle, which as you may remember was precisely what it was designed to do. So the scene wound up being done entirely with digital effects, even though it was shot from the exact same angle that the prosthetic was built for:

That's like taking a superbly crafted Halloween mask back to the store because it doesn't look right when you wear it inside out. Whereas before, when you had to construct a shot around a visual effect, Hollywood has spent the past 20 years doing the exact opposite, and it has made directors reluctant to commit to anything until the day of filming. Since practical effects take months to prepare, this trend has effectively hamstringed the industry. You can't make a quality monster if you have no freaking idea what it's supposed to be doing in a given shot.

And while we're on the subject ...

As we said, provided everybody is doing their jobs properly, CGI can end up being nearly flawless. Lord of the Rings created an incredibly lifelike and believable Gollum back in 2002:

New Line Cinema
"The original plan was to just have Andy Serkis start doing meth, but the insurance wouldn't cover it."

Ten years before that, Jurassic Park had photorealistic dinosaurs designed entirely by a computer:

Universal Studios
The poop in 10-year-old you's pants? That was real.

So why bother with practical stuff at all? Well, the reason those CGI creations look so great is because the people behind the computer screens had a lot of real-world stuff to base their techno-wizardry on. Building models, puppets, and costumes gives digital effects artists a baseline frame of reference when sculpting their computer-generated, joy-inducing turbo dinosaurs.

"One of the myths about Jurassic Park is that it was primarily digital," says Gillis. "Stan Winston told us that he sat with a stopwatch and timed the film. There are 11 minutes of dinosaur, and four [of those minutes] were CGI. The other seven were all practical."

Universal Studios
Including our least favorite minute.

"I also suspect that the reason Weta [the effects house behind Lord of the Rings] does such great digital character work is that they also have their foot in practical effects. They'll build heads and then scan them and examine them. They see the practical effect as a necessary asset."

Woodruff and Gillis have used this exact process to produce some of their best work. For instance, Alien vs. Predator, regardless of what you think of the movie, has an awesome CGI alien queen:

20th Century Fox

According to Gillis, "The digital queen looks great in part because we had a real queen there. They could match that." The reverse is also true -- practical effects can easily be augmented with CGI, which was the conceit the duo were operating under when they designed their creatures for The Thing (they figured the digital effects would be used to add more freaky tentacles to the monsters or something, rather than replace them entirely). "We can't take the position that one art is better than the other. CGI is every bit as artistic as practical effects; they just have different results."

The point is, the best way to accomplish the coolest monster movie stuff is with a combination of both, but right now, the moneymen at Hollywood don't think that practical effects are worth the effort. Which is too bad, because ...

The above may sound like a contradiction -- coming off all of their praise for CGI effects and all -- but Woodruff and Gillis say the problem with CGI is that it's being asked to do stuff it was never intended to. For a great example, look no further than Transformers, the cinematic equivalent of a fat man in a business suit sitting on a pile of money shouting, "We'll fix it in post!":

Everyone on the visual effects team responsible for that movie did a perfect job, we suppose, but they can't possibly get everything, because they're being asked to add in too many elements that weren't captured on the day of filming. For instance, why don't the cars shake when the thousand-ton robot stomps on the pavement, and why aren't any leaves falling off those trees as robots of equal size explode just a few dozen feet away? Why are there always one or two extras that respond in ways that don't quite make sense? Because none of that stuff was actually there -- all the director did was hang a tennis ball up in the air for everyone to stare at and film a few solid minutes of nothing.

You may not think you're noticing these things, but like so many other little details in storytelling, your brain is subconsciously being reminded that what it's seeing isn't real. Compare that to this scene in Tremors, wherein one of the worms explodes into a concrete basement and attacks two Second Amendment advocates with a wall full of guns:

No one had to individually render where each dust particle fell, or make sure the blocks of concrete tumbled to the floor in an appropriate trajectory, or meticulously explain to the actors what the monster looked like so they would know how to react -- they just built a giant rubber monster and rammed it through a f*****g wall. That's what you lose in an all-CGI world.

If you geeked out about Tom Woodruff and Alec Gillis' work as much as we did, check out their new movies, the alien monster flick Harbinger Down and the demon-horror film Fire City: Interpreter of Signs.

For more insider perspectives, check out The Gruesome Truth About Getting Shot (a First-Hand Account). And then check out The 30 Most Ill-Conceived Movie Monsters.