-1

I'm a big fan of the Pixar movie The Incredibles. I especially love the animation. However, there's one point I've been wondering about: the strength of gravity.

Unlike some other styles of animation, Pixar tends to create physically-realistic motion, including how long things take to fall. However, in at least two sequences in The Incredibles, people fall at far too fast for reality. I'm wondering why, when the highly-professional studio virtually always gets it right, they seemed to get it way wrong here.

In the first case, Mr. Incredible konks a bad guy with a coconut (at about 58:38 on my copy), causing him to fall off of a platform:

enter image description here

The guy takes about a second to fall about ten meters, giving an acceleration of about 20m/s^2, or double gravity.

Another incident is more egregious. Here, Mr. Incredible drops Mirage after threatening her (at 1:23:17):

Dropping Mirage

She takes about 1/4 second to fall about 2 meters, giving an acceleration of about 64 m/s^2, or six times gravity. (BTW, in converting the video to GIFs I messed up the frame rate, so the GIF durations are probably wrong.)

Unlike classic Warner Brothers cartoons, these aren't plot points where the breaking of physics entertains. And, not only is the physics wrong, but it just looks wrong, which leads me to wonder why Pixar did it that way. Given their overall excellence (how many Academy awards?) my best guess is that, for some other reason, high gravity generally makes the animations look somehow "good" (realistic, fun, exciting) and they didn't adjust it when something actually fell freely. Or, maybe it's just a mistake.

So, my question is: why did Pixar do this motion "wrong", where they spent so much effort doing it right elsewhere in the movie?

  • 15
    I don't think standard rules of physics apply for an animated movie. – bobbyalex Jun 16 '15 at 9:03
  • 13
    We're talking about a movie with superheroes, plus it's animated, and the question has to do with the reality of the phyisics? Shall we discuss the reality of Wile E. Coyote's antics? – MattD Jun 16 '15 at 17:32
  • 6
    This is a silly question. Even if you feel like you have to take the physics of an animated comedy movie seriously, you can't judge the speed of gravity from such negligible distances. – DisgruntledGoat Jun 16 '15 at 22:31
  • 2
    I'd suggest re-titling this something like "why do characters sometimes fall more rapidly than looks natural"; the current title is kind of ridiculous and may be contributing to the negative feedback you're getting. – Kyle Strand Jun 17 '15 at 14:23
  • 3
    I like the sudden exaggerated fall of the guard scene, I think it works well with the pace of that sequence and looks pretty hilarious :) I wouldn't want a realistic fall to be honest, if things like that look too real takes you away from the comedic side of things. Just my opinion though haha – tohood87 Jan 18 '17 at 16:22
12
+50

'Uncanny Valley' isn't really a problem unless you're really trying to go for perfect human representations with CGI. It's where 99% feels real but that 1% is off like a weird lip movement or something (ie Rogue One). In this case with Pixar stuff, they never aim for perfect reality so the 'Uncanny Valley' argument isn't necessary.

If you look at Toy Story, everything is pretty spot-on with how characters and objects interact with the environment. Woody's legs dangling like they should, things falling over like they should etc. Pixar have done an amazing job to recreate 'real-life' gravity in a hyper-reality world. This actually makes the 'breaking of the gravity rule' feel more dramatic and the same goes with The Incredibles. That's why I mean I think the change in gravity you noticed would be for dramatic reasons.

If you watch Madagascar, the characters are flipping and flying all over the place and the movie struggles to establish a gravity rule in that world (the big hippo jumps like, 3-4 metres into the air and into a pool). This is a totally fine creative choice but I think Pixar are amazing at making their films feel grounded by keeping their gravity rule consistent for most of the movie.

I could talk about this stuff forever so let me know if you need more info.

  • 3
    What lip issue in Rogue One? – cde Jan 12 '17 at 4:20
  • Thanks for this answer. If you add a few more details of why Pixar might have understated the time passed during these falls I'll mark this as correct. – Daniel Griscom Jan 12 '17 at 15:21
  • 2
    Because it's funnier when it's quicker. – Ross Jan 12 '17 at 16:26
  • @Ross These aren't points where surprising physics would be funny; see the animated GIFs I added to the question. – Daniel Griscom Jan 12 '17 at 20:08
  • 3
    @DanielGriscom The first one is actually hilarious – Ross Jan 12 '17 at 21:29
20

Because the standard rules of physics don't apply for an animated movie.

More technically, if an animator tries too hard to get the physics to perfectly mirror the real world, you end up in the uncanny valley. There's a blog post at Fast Company Design that touches on this topic a little, where they talk about Disney's 12 Principles of Animation created in the 1930's.

The goal of animation is not realism, but the illusion of realism. For example, in rotoscoping, you film an actor and then laboriously trace over the images to convert his or her movements into a living cartoon. But unless you constantly tweak what you're tracing for the medium of animation, the results look creepy. The lesson? The goal is not to make objects move as realistically as possible, but rather to make them move as fluidly as possible, regardless of realism. Good animation requires entirely different laws of physics.

  • 2
    Rather than just linking to the wiki page for "uncanny valley" I believe it would strongly help your argument to explain what it is. – Catija Jun 16 '15 at 21:16
  • 3
    This doesn't really explain any connection between falling speed and fluidity. – Kyle Strand Jun 17 '15 at 14:21
7

Because exaggerated motion in the frame is what makes animation worth doing over live action in the first place.

In animation, jokes and visual gags are timed according to audience expectations and not the physical world. There is a sliding scale between letting your audience notice a joke before it happens and barely letting a gag register before showing the reaction:

Timing is very important for jokes, spoken and visual. Cartoons run at the speed of your brain, not at the speed of time. So I guess my question for you, regarding your two examples, is how did those two gags play with your expectations of what you thought would happen? This is the whole point of exaggerating motion, to surprise or heighten the audience's reaction or understanding.

  • But, the points where I note in this movie do NOT seem to want to attract attention to them. I'll edit the question to make that clearer. – Daniel Griscom Jan 12 '17 at 16:04
  • 2
    BTW, that's a very seductive GIF... I wonder if it could installed as a desktop image. Might harm productivity, though. – Daniel Griscom Jan 12 '17 at 20:25
5

This is my first answer and I hope I don't mess it up.

Pixar tends to create physically-realistic motion, including how long things take to fall. However, in at least two sequences in The Incredibles, people fall at far too fast for reality.

I disagree with this part, and I have strong evidence. Take for example, the Up movie. As far as I know, it defies most laws of physics and contrary to The Incredibles, it has very little respect for the gravity! But it was really fun to watch. Because when I am watching an animation, I expect fun and not reality.

Sometimes the reality is itself a way of adding fun. For example, those details in the furry animals of Monsters Inc. cost very much (you won't see such details in low-budget movies), but they totally worth it. It made them ridiculously believable, and I made a strong bond with them because of that. I hope you know what I'm saying ;)

So I think the makers of animation movies need to keep a balance between the reality and fun. And paying attention to all the laws of physics adds no more fun to the picture. The budget needed for an animation is typically higher than a real movie (Citation needed of course. I am talking about a few examples that I have checked). So if we want something to totally comply with the reality, why bother making an animation?

4

A world has rules and most of the time the animator follows these rules and in this case it's gravity. Pixar do a pretty good job at keeping the gravity rule constant throughout a movie but in this case with the incredibles, I'd say they broke this gravity rule for story-pacing reasons or for more visually dramatic reasons.

  • @Chenmunka I disagree. The other answer claims that Pixar broke the rules of gravity to avoid the "uncanny valley", which makes no sense to me. This answer seems more reasonable, although I'd like some more details. (Javed, I've added times to my question.) – Daniel Griscom Jan 10 '17 at 12:40
  • BTW, your other answer is better, and is mostly an elaboration of this one. You should delete this one. – Daniel Griscom Jan 12 '17 at 15:26
2

Gravity is fine - your calculations are wrong.

First example you give is "10 metres in 1 second" - which is a speed of 10m/s, not 20m/s as you state.

Your second example is 3 metre in 1/4 second - which is about 12m/s, not 100.

Now, I assume you're taking gravity as 9.8 m/s, so that makes those two falls only slightly faster than in reality, which can be put down to comic timing.

Although, remember that gravity doesn't have a fixed velocity, but instead has an acceleration - 9.8 m/s/s.

So I used this nifty little calculator, it said the first guy should take about 1.43 seconds to fall, and the second guy 0.78 seconds (based on a body mass for each of 70kg).

So they're moving faster than they should, but not as much as you thought. I'd say it's just comic timing.

Oh... and the first guy is probably dead.

  • Don't you know? Only parents are allowed to die in Disney movies. The guy is lucky he never had kids thanks to his life of crime. – cde Jan 12 '17 at 4:22
  • 4
    Gravity is 9.8 meters per second squared; things don't fall at a constant 9.8 meters per second. Distance = 1/2 * acceleration * time squared. So, a dropped object should fall 4.9 meters in one second, or only 0.3 meters in 1/4 second. See here for details. (And you're right: the first guy is probably dead.) – Daniel Griscom Jan 12 '17 at 12:11
  • 1
    Sorry but I've had to give this a -1. The original questions's statements about the gravitational acceleration required to achieve those times to fall are approximately correct - then you compare them incorrectly to values that don't use acceleration. Also the body mass used in the calculator is irrelevant to acceleration over these short distances (it is irrelevant in a vacuum entirely and doesn't affect your scenario here until the effects of terminal velocity in air come into play). The calculator you link to only uses your 70kg for the energy at impact. – iandotkelly Jan 12 '17 at 16:03
  • The acceleration is (2 x height) / (time-squared). So 10 meters in 1 second is about twice gravity, and 3 meters in 1/4 second is 6/0.0625 which is about 10 times gravity. My point is that far from the "calculations are wrong" - the calculations are actually pretty spot on. – iandotkelly Jan 12 '17 at 16:23
  • 1
    The calculator said the first fall should have taken about 1.43 times longer than it did, and the second fall should have taken about 3.1 times longer than it did. Remember that the formula has the time factor squared, so to figure out the implied acceleration error you need to square the time error. In the first case, 1.43 squared is 2.05; I said the acceleration was off by a factor of 2. In the second case, 3.1 squared is 9.6; I said the acceleration was off by a factor of 10. The calculator and I agree to within ten percent. – Daniel Griscom Jan 12 '17 at 19:24
1

You are putting something there that isn’t...they don’t speed it up for effect, instead they don’t draw it out for effect.

Making the times realistic isn’t necessary and is in fact distracting. It makes the scenes longer without doing anything but give the audience a chance to be distracted. Take the guy on the roof — once he starts falling off the roof it’s all over but the impact. He has no interaction with the rest of the universe until he hits the ground. If they make that take 2 second that is 2 seconds without plot, dramatic or character action.

It would in fact be entirely understandable if a non-animated movie did the same thing, cut frames in order to speed up the fall and get on to the next scene faster.

1

So I was curious about the math being flung around here, and decided to have a look at it.

plot1

Using mathematica, and a standard angled throw equation, with some guesses, we can have a pretty good guess as to what's going on here.

First, I assume Mr. Incredible is 2 meters tall...He's probably taller, but the error of margin is negligible...

I assume he throws at about 30 degrees (that's pi/6 in radians) with -9.8 as gravity.

Solving for when the coconut is at the ground gives us a closed margin of where, and how far things are.

We can see it should take approx three seconds, throwing the coconut at 100km/h (27m/s) (Mr Incredible is apparently over 1500 times stronger than a man who can lift 100kg, benching 155tons (I assume imperial tonnes, ie 2200lbs), he could have likely vaporized the guy if he really threw the coconut...but I'm getting carried away)

Anyways, I watched the scene and in super scientific, clicking youtube videos repeatable for peer review fashion, I see it took 1 second for the coconut to arrive, Which means the solider guy was 10.95 metres above the ground.

thing2

Your initial guess was, 20m/s^2 ( I assume you actually meant 20m/s^2

Solving for that gives:

thing3

Giving us an acceleration at -22m/s^2

So, yeah, he definitely fell pretty fast. I won't bother solving for the girl, though, in reality she didn't fall 2 meters, she fell probably less than a metre, landing on high heels off balance and falling to the ground. (The speed of things falling on a curve can get quite fast! which probably makes it seem like she fell faster than it should be.)

Math aside however, I couldn't say why that particular scene seems to be so quick, compared to others, and if they're using some kind of rendering/physics engines, like in video games, and simulators, they wouldn't change the acceleration of things just for single scenes, if it wasn't intentional.

This concluding, they intentionally increased the acceleration for some kind of effect, as in other comments pointed out, changing physics for a specific kind of effect can make it more dramatic, or suspenseful, or even funny.

It wasn't a funny scene, nor a dramatic one (in comparison to the girl falling, which would also explain the changing of her falls acceleration), but it was an sneaking around action scene, changing the accel. here makes no contextual sense.

Thus it could be quite likely be a mistake or more likely to me. They just wanted it over quickly. Rendering time costs money.

Addendum

The OP was correct in their comment in pointing out that the model of the coconut throw, assumes correct gravity, but a screwy fall. Which points further to the fact there is an intentional change in physics.

To delve further into the conspiracy, I have modelled friction, into the equation to find out if this is playing a roll of any kind.

plot5

The orange curve being with drag, blue without. Assuming a weigh of 600 grams and a coconut 300mm in diametre.

This barely changed anything. a new height at 1 second of 9.84213 metres.

This reduces the accel. to -19.6843m/s^2. This with a correctly modelled coconut throw, giving us an incorrect fall.

So I applied the same to a model with drag, and at ~19 m/s2

thfasdf2

Here we see quite a big difference between our two systems and how far the guard fell. Taking the maximum height of 4.84445m and solving for the accel. Gives what I expected:

thing5

A complete reversal of physics, and the expected acceleration. Uff, that's not good.

Lets see how fast the guard actually fell, if they fell at ~-19m/s^2.

other324

Oh..0.7 Seconds. Seems about right, considering my youtube clicking.

The OP seems to have simply stumbled onto the fact that gravity within the entire movie is actually twice that of reality in all scenes. Nice catch!

  • Hi, and thanks for the answer. Interesting approach on the coconut throw, but doesn't that mean you're assuming they're modeling the coconut trajectory accurately, which means it feels one Earth G, where the guard apparently doesn't? – Daniel Griscom Feb 18 at 19:22
  • Hi, yes, quite right, please see the addendum. – morbo Feb 18 at 21:19
  • Very interesting hypothesis. I'll have to take a look at some other points in the movie. – Daniel Griscom Feb 18 at 22:32

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .