The 7 Most Common CGI Screw-Ups (Explained)

The 7 Most Common CGI Screw-Ups (Explained)

If you've watched movies in the past 10 years, you've probably at some point complained about horrible CG, because you movie viewers are ungrateful little jackanapes.

Every time CG goes well and blends seamlessly into the movie (I bet you didn't know it was used in Brokeback Mountain), people rave about the amazing acting performances and the wonderful storyline and maybe the great soundtrack, and every time it goes wrong, everyone talks about how CG is terrible and is ruining movies.

The 7 Most Common CGI Screw-Ups (Explained)

I'm not joking, watch the video.

But that's OK, whatever, it's a job, nobody says thank you to accountants and insurance underwriters either. I can't brag to anyone about having worked on The Mummy: Tomb of the Dragon Emperor, but it put food on the table. But you know, as long as we're criticizing crappy CG, I thought maybe you'd like to know more about the details of how each terrible disaster unfolds behind the scenes, and more importantly, who to point fingers at.

Here's some of the more common complaints:

Skin Looks Like Plastic

The 7 Most Common CGI Screw-Ups (Explained)

One of the creepier CG sins is to make skin look like plastic. This was only one of many many things wrong with the Scorpion King character above, who actually only appeared in scorpion king form in The Mummy Returns and not in any of the three movies actually named The Scorpion King, because Hollywood likes to confuse us. (Yes, it had two direct-to-DVD sequels. No, nobody watched them.)

When moviegoers say skin "looks like plastic," it can mean a few things. Sometimes they mean faces are rigid and motionless, as if they were made of hard plastic like some kind of creepy doll, which is usually a rigging problem, which I'll talk about later. Sometimes they mean the skin has the texture of plastic, like their face has been shellacked.

But he kill was sent to youl

Sure, this was 11 years ago, but let us note that the Rock lent his face to this hilariously shameful visual effect the same year that the first Lord of the Rings movie came out.

The 7 Most Common CGI Screw-Ups (Explained)

They hadn't reached their full potential yet (Gollum comes along in the later movies), but clearly, plastic-Rock-head-pasted-on-monster was not "the best you could expect from CG at the time" by any means.

One of the (numerous) things they would do to make Gollum look much, much less like a bad video game character than the Scorpion King was to make his skin not look like frickin plastic. The person responsible for this is the person who writes the shaders. When a character is modeled, or "sculpted" in 3-D, at first it has no color. When modelers show their work for approval, it usually looks like a statue made of dull gray clay.

In fact, freelancers will sell models at this stage. This one is going for $275 on TurboSquid:

The 7 Most Common CGI Screw-Ups (Explained)

A shader writer is a person who writes a program that tells the computer how to "paint" the model -- not just what colors, but how shiny or dull, how bumpy or smooth, how transparent or reflective it is, depending on a bunch of factors, like whether it's facing you or you're looking at it at an angle. Lots of science.

Skin is made of a lot of layers, so it's really complex, and they were really far from figuring it out back when Toy Story was made, for example, which partially drove the decision to make the movie about a lot of plastic toys and not about humans with skin.

The big breakthrough was a thing called subsurface scattering. Read that linked tutorial if you want to find out more about it, but basically, it accounts for light bouncing around through all the layers of the skin so your character stops looking like the picture on the left and starts looking like the picture on the right:

The 7 Most Common CGI Screw-Ups (Explained)

When they finally figured this out, they used it on Gollum, The Incredibles and everything else. Any skin that looks like plastic today doesn't have the "we don't have the technology" excuse anymore. Some asshole is dropping the ball or skimping on the budget.

Character/Vehicle Looks, Uh, Wrong

The 7 Most Common CGI Screw-Ups (Explained)

In the case of Anaconda 3, I mean this literally. The snake looks like a snake that was born, through no fault of its own, with significantly impaired cognitive function compared to other snakes.

Now, Anaconda 3 clearly had a budget of about five dollars, and for most people, that's reason enough why the CG would suck. But that makes it sound like all the problems are technology problems, like they couldn't afford computers good enough to magically make a snake that is shaped like a snake, for example. Technology and money are needed for a lot of things, like complex shading and rendering of skin and water and that kind of thing, but it doesn't take money to make a snake shaped like a snake, it just takes a person who knows what a snake looks like.

The 7 Most Common CGI Screw-Ups (Explained)

Not like this.

There's a couple of people who might have dropped the ball. One is the art design team, who usually draw up 2-D drawings of the characters they want to make for the film. These drawings get handed off to modelers, who then "sculpt" the characters in 3-D on the computer. Their finished product is the gray-clay-looking models pictured in the previous entry.

The art team might have drawn a shitty snake, or the modeler may have bungled the attempt to create a 3-D model out of it or, considering the movie we're talking about, both of them were probably the same person, the director's nephew who just got out of animation school or something along those lines.

Sometimes the blame goes a bit farther up, as there is usually a chain of command that has to approve the art team's designs, as well as the resulting models. Here's a couple of widely reviled vehicle designs courtesy of Star Wars Episode I and Star Wars Episode III:

The 7 Most Common CGI Screw-Ups (Explained)

The 7 Most Common CGI Screw-Ups (Explained)

There's nothing wrong with the execution by the modeling team -- they are very well done and realistic-looking models of stupid vehicles. The drawings were shown to the art director and the VFX supervisor, and probably went straight to the director/producer -- I don't have time to look up who that was -- and he approved it.

Ang Lee's The Hulk is going to come up a lot, because it was a VFX abomination, but one of the biggest complaints was about the unrealistically bright green skin on the title character (Jennifer Connelly). People heap a lot of scorn on the VFX team from ILM (Lucasfilms' award-winning Industrial Light & Magic) for this, but what they don't know is that their original tests had more toned-down, realistic versions of the green Hulk skin, but when they showed them to the director -- again, I don't have time to look up who directed Ang Lee's The Hulk, but you can probably find it on IMDb -- he nixed it and said, "No, it needs to be more green!"

The director's word is law, so they have to do what he says, and now everyone thinks ILM's VFX team doesn't know what skin looks like. Now people think Rhythm & Hues' team (on 2008's The Incredible Hulk) is just smarter than them.

The 7 Most Common CGI Screw-Ups (Explained)

ILM's 2003 Hulk is on the left, obviously, and R&H's on the right.

The lesson is that if you have a director or art department with no taste, there is not a thing the dozens or hundreds of CG artists can do about it, except follow orders and make the awful things.

Looks Like It Was Done in Photoshop or MS Paint

Well, while we are talking about Ang Lee's The Hulk, why not set your eyes on these beauties.

The 7 Most Common CGI Screw-Ups (Explained)

This scene actually happened in a big budget blockbuster done by ILM. Seriously, watch it. He really has that white outline around him and he really freezes in midair like he is in the end credits of an '80s sitcom, while the fire moves behind him.

I get that Ang Lee was trying to imitate the look of a comic book in the movie -- it's pretty clear from the millions of distracting, terrible split-screen effects he put in every other shot. Unfortunately, I don't think he understands that comic books have a lot of still poses because they are, you know, drawings, and not because comic book fans like all their action scenes to be a series of frozen poses. Comics fans are actually very happy about watching their heroes come off the paper and move around.

Another gem from the same movie:

The 7 Most Common CGI Screw-Ups (Explained)

Did you say to yourself, "That looks like a Photoshop filter"? Because it looks like a Photoshop filter. I think it might literally be one. I did not do anything to that image, it is a direct screenshot from a movie that cost $137 million to make. Have a closer look.

The 7 Most Common CGI Screw-Ups (Explained)

When you see this in a movie done by ILM or some otherwise respectable VFX house, there is only one explanation. The director has gone insane.

The director is always the final word on VFX, and this absolute power means they can take a group of professionals responsible for things like Jurassic Park and direct them to apply a Photoshop filter to a scene where Nick Nolte inhales gas from a vacuum hose. You usually don't see the consequences of such a drastic gap between a team's knowledge of VFX and a director's almost negative knowledge of the same because you usually don't take a guy who directs historical dramas about repressed societies and tales of longing and make him absolute dictator of a Marvel comic book movie.

(I assume for Brokeback Mountain, they reduced his level of input on VFX dramatically, because the sheep all look like sheep.)

But seeing the problem at its extreme in The Hulk kind of makes you think about how many other movies you might have been blaming the VFX team or "bad CG" in general for when the director or supervisor just happened to be an idiot.

Characters Move Like They Are Floating or Spastic

The 7 Most Common CGI Screw-Ups (Explained)

I never watched Blade II, I've only been referred to it for "some of the worst CG ever," and those people did not steer me wrong. It's the herky-jerky animation in particular that really stands out, which obviously you can't see in a still photo, so you'll have to watch the clip (check out the beginning and 2:12):

The person to point and laugh at here is the animator. After the character has been designed and the modeler has built the model, it's the animator's job to move the model around and make it run or jump or have facial expressions or, in the case of Blade II, bend and snap erratically like an unevenly weighted slinky dog.

Blade II came out the year after Jurassic Park III (skip to about 1:30) ...

... which contained raptors that moved like real animals. But again, animation isn't a technology or budget thing. Things like gravity and mass and acceleration and human anatomy haven't changed for, I don't know, like 6,000 years, since the earth was created. People have understood how to re-create it through moving drawings since the beginning of the 20th century.

Being able to animate is like being able to draw. It's about observation, study and talent. Having a low budget might mean you get bad animation only in the sense that you can't hire good animators, but there's no computer magic to animating a back flip correctly, just a guy (or girl) who knows what a back flip looks and feels like. There are cheap one-man movies with amazing animation (that one got him hired by Pixar) and expensive blockbusters with beautifully rendered, but spastic, characters.

That's why I'm calling out Jumanji, even though it was made in 1995. That might excuse the monkeys' fur and faces looking fake, and them not blending well into the scene, but it doesn't explain why the monkey coming out of the store with a monitor looks like a stormtrooper from a 1930s newsreel:

While we're here, also enjoy some American Werewolf in Paris (try 5:14 to 5:29):

I know it's hard to focus on the bad animation when there are so many other things wrong with this clip, but if you watch it enough times you'll pick it out or maybe become suicidal, one or the other.

And finally, I don't have a video to link to, but maybe a screenshot of this Star Wars Episode I scene will bring the memories flooding back:

The 7 Most Common CGI Screw-Ups (Explained)

Just like money can't buy you good dialogue, it can't buy you natural animation either.

Stiff Faces

The 7 Most Common CGI Screw-Ups (Explained)

Often cited as one of the creepiest movies ever made, sandwiched between Nosferatu and The Exorcist, Polar Express usually gets called out for its creepy eyes. While the eyes alone are sufficient to transport the viewer into the uncanny valley, another big source of unintentional horror is the stiff faces.

This is a big problem in a lot of near-photorealistic motion capture movies. They're essentially pasting a photographed human face onto the model, like a sticker wrap, and the motion of the body is lifelike, since it has all the minute swaying and tiny movements of a real actor, but facial movement is still as limited as Woody from Toy Story or Keanu Reeves in The Matrix.

The 7 Most Common CGI Screw-Ups (Explained)

More so on one than the other ...

This looks fine on Woody, since he is a cartoon toy, and his limited facial movement matches the cartoonish movement of his body and the cartoonish look of everything around him. On a near-photoreal model, however, it looks like the little girl has been embalmed and can only move her eyes and jaw.

In this scene from mocap and acting masterpiece Final Fantasy: The Spirits Within, characters move their eyebrows, nose, mouth and eyes like they are all separate pieces moving independently.

Sometimes animators are to blame, because in the end, you've got to move the parts right, but most of the time, stiff faces come from limited rigs. You see, after the model is made, but before the animator starts moving it, riggers come in and rig the model with all kinds of controls. They put in a skeleton, so that if you bend a joint, the arm bends, or they designate areas on the skin (like a cheek) that move when the animator turns a dial or types in a number. This is basically like putting the strings on a marionette and handing them to the puppeteer (the animator).

The 7 Most Common CGI Screw-Ups (Explained)

Fittingly, marionettes are also creepy as hell.

If you don't give the animator any controls for cheek muscles, for example, the animator couldn't move the cheeks even if they wanted to. Human faces have, like, a million muscles (I didn't take anatomy), and you have to give animators a shit ton of complex controls in order to make a realistic-looking human face move as realistically as it looks. They didn't have the experience or software to do it in Polar Express and Final Fantasy, but the team on Avatar managed to figure it out. So now nobody has an excuse.

These are all mocap movies, so a lot of the problem was also how to get the data from actors' faces automatically onto the CG faces, which is a pretty hard thing to do. Usually, no matter how good the process is, you still have an animator going in and touching it up, so a lot of it depends on how well a guy can look at a video of someone's face and click his mouse around on a computer to make the CG face match it.

Characters Don't Look Like They're in the Same World

The 7 Most Common CGI Screw-Ups (Explained)

The dinosaur stampede in King Kong was infamous for "looking like bad green screen." At times it looked like Adrien Brody, Jack Black and numerous forgettable cast members were actually running in front of a dinosaur movie playing on a wall behind them.

You expect that kind of laughable B-movie effect from Jean-Claude Van Damme's Derailed:

The 7 Most Common CGI Screw-Ups (Explained)

But it's kind of weird to see it in a Weta (Lord of the Rings, Avatar) movie like King Kong. All I can figure is that they were rushing the crew -- too many shots in too little time. Technically, what's wrong is the compositing. Compositing is when you take all the stuff that has to go together -- backgrounds, CG characters and props, live actors shot on green screens -- and put them all together.

It's basically like doing Photoshop on a moving picture. You get shitty compositing for pretty much the same reasons you get shitty Photoshop. The characters aren't cut out well (green screen matte extraction was done badly), the lighting doesn't match or the focus doesn't match. You can see some lighting problems here:

The 7 Most Common CGI Screw-Ups (Explained)

Even when Jack Black runs under the dinosaur and should be completely in the shade, his hat stays bright. It's not like most people really notice that specifically, but when you watch the scene play out, your brain tells you something is wrong and you can't put your finger on it. There's also some shots where the actors are way too sharp compared to the background.

The 7 Most Common CGI Screw-Ups (Explained)

I mean, yes, obviously they should be sharper than the background, because the background is moving and has motion blur, whereas the camera is following the actors, so they should be more in focus. But if they'd gotten the relative focus of each object correct, it wouldn't look like ass when you saw it in motion, and it looks like ass when you see it in motion, which means there's too much blur on something or not enough blur on something else.

The 7 Most Common CGI Screw-Ups (Explained)

Maybe it's the edges of the actors that need to be blurred to blend in. I don't know, I'm not a compositor. If you know the answer to this, try going into comp, it doesn't pay too bad if you are good at it.

Fortunately, sometimes bad compositing can be so bad it's funny, as in this Gone in 60 Seconds clip (start at about 7:22).

Here's the crucial shot if you missed it:

MY: Aa 1s

Man, it's like someone cut that wall open with an X-Acto knife.

Clothes Look Like They Are Pasted On

I tried to stay away from The Hulk, but these pants really have to be addressed.

The 7 Most Common CGI Screw-Ups (Explained)

These pants look like pants from a video game. A video game from 2003, when this movie came out. The fake-looking surface is a texturing/shader issue like I talked about before. It's pretty egregious, but that is not the worst thing. The worst thing is that they appear to be painted on him.

See, a character moves around when you move a skeleton, which is pretty much what it sounds like -- imagine a bunch of joints connected by wire, and then you sculpt soft clay around it. You bend the joints, and the sculpture moves. There's two ways of making the model move. One is that you say it's pretty much like clay that's attached to the skeleton. This is called "skinning." When it goes wrong, you get melty faces and Gumby elbows.

(A lot of tutorials cover the "collapsing elbow" problem.)

The 7 Most Common CGI Screw-Ups (Explained)

The other thing you can do is a simulation, which is something you do for hair and cloth and tassels and maybe dangling genitals or something. You tell it where it's attached, or pinned, to the skin or skeleton, and it sticks there, and everywhere else it uses a bunch of complex physics equations to tell it how to move. Like with a skirt, you tell it the waistband is "pinned" to the character, and the rest of it figures out what to do based on the pinning and air resistance and whatever it crashes into.

The Hulk's pants had a minimal amount of simulation, if any, so it looks like a second skin, which looks weird most of the time, but looks absolutely bizarre during certain movements, like this:

The 7 Most Common CGI Screw-Ups (Explained)

What the hell are those pants doing?

The 7 Most Common CGI Screw-Ups (Explained)



The 7 Most Common CGI Screw-Ups (Explained)

OK, I've got to go watch Crouching Tiger, Hidden Dragon again so I can stop being mad at Ang Lee. Now that you are a CG expert, I will leave you with this clip as a test to see if you can identify what parts went wrong. (Hint: Everything.)

For more from Christina, check out The 5 Miserable VFX Jobs That Make Movies Possible and 4 Reasons 3-D Movies Don't Have to Suck.


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