Science Fact or Cinematic Fiction: Gravity
Gravity may be the most ubiquitous of all physical laws among the layman. Its effects are witnessed constantly by everyone throughout their entire lives so this is not necessarily a surprising fact. What is surprising, however, is the amount of leeway the typical audience is willing to give entertainment media in its violation of this rule. The only loose consistency among film, games, and animation in regards to gravity is that it’s still generally in the downward direction. Aside from that, these three mediums will either stretch or entirely disregard the rules associated with this aspect of the physical universe for the sake of cinematic titillation. Typically, these violations are made to great success in arousing excitement in the viewer.
Breaching the rules of gravity is an easy way to appeal to the very primal emotions people associate with falling or flying. Exaggerating a fall from a ledge or building in film can incite a nervous uneasiness in the pit of the audiences’ stomach similar to what they might feel were they actually in the situation that’s happening on the screen. Likewise, giving the player-character in a video game the ability to fly may invoke an enlightening sense of freedom in the player as they’re suddenly able to explore a virtual world without borders or perform physical feats that in reality would be impossible for them. The explanation of the logic in either of these cases or the innumerable situations similar to them is minimal to non-existent, but the satisfaction they provide makes us willing to accept such impossibilities. When it comes to entertainment, regardless of the medium, gravity gets no respect.
Situations exhibiting nonsensical gravity occur often in film and games that involve interplanetary or interstellar travel. Among these titles, perhaps there is no more popular offender than the Star Wars films. When travelling about the vastness of deep space in starships, characters are always free to roam around the cabins unhindered by what should be zero gravity situations. There is no reasoning behind this in the films, though official Star Wars lore mentions a vaguely described device called an “artificial gravity generator”, which operates as a pseudonym for a magical force providing this gravity since current science is unaware of any means by which artificial gravity may be conjured by a single object onto another object and everything within it. Furthermore, there is a scene in second Star Wars film, The Empire Strikes Back, in which the characters land inside of a giant worm that dwells within a large asteroid. Uncertain of the situation, several characters exit the confines of the ship and walk around to explore the “cave” they’ve landed in. Here, the rationale of an “artificial gravity generator” is invalid since they presumably ventured beyond its influence when they left the ship and a body the size of an asteroid wouldn’t have enough gravity for the characters to move as if they were experiencing gravity similar to that on Earth. On the other hand, concerns about gravity are only one issue with this scene as the matters of air pressure and and temperature would also add complications.
So, is Star Wars guilty of ignoring the logic and laws of gravity for the sake of its fiction? Certainly. But is it alone in this violation? Well...
While live action may often utilize an elastic approach to gravity to simplify production or enhance action, in animation the laws of gravity may be broken for an even greater variety of reasons. A complication of the medium of animation is that every element in these films are fabricated from scratch. Gravity can just as easily be intentionally unbelievable as it may be unintentionally so. Also, in animation the rules of gravity may be subject to change constantly within the film, such as in Disney’s Tarzan. Leaping feats performed by the title character are far beyond what his less acrobatic and civilized counterparts can achieve not only due to his apparent superior physical strength but due to a seeming capability to suspend the effects of gravity when needed. For instance, during a chase scene that takes place approximately 35 minutes into the film, Tarzan performs some extreme vine swinging in an attempt to rescue Jane from angry apes. At the end of the chase, he makes one huge swing that launches him up from the trees he’s swinging on, out past the canopy, and onto one of the highest branches in the visible rainforest.
Tarzan, buddy, why not go to the moon while you’re at it?
While it’s tough to gauge the total distance traveled during that behemoth-of-a-swing due to inconsistent camera angles and motion in perspective, if we measure the slightly crouched Tarzan in that final frame as 5ft high, then Jane’s position at the peak trajectory stands about 20ft above that. Assuming that the total distance of the swing is only 40ft (the additional 20ft coming from the distance between the vine and the treetops in the first shot and the treetops to the bottom of the large branch in the second shot), then Tarzan managed to gain enough speed by swinging horizontally on vines to propel the combined weight of Jane and himself the equivalent height of a four story building. Furthermore, the effects of gravity operate on an object’s vertical motion at a parabolic rate. Regardless of whether an object is approaching its apex or descending from it, the acceleration or deceleration of motion should reflect this rate. If the rate of change in speed is identical for an object regardless of whether it’s traveling with gravity or against it, than the “Fourth Down at Half Time” rule should match up with Tarzan and Jane’s motion in this shot when played in reverse (“Fourth Down at Half Time” refers to the fact that an object will fall a quarter of the distance from its apex at half of the total time we are witnessing the fall). The entire upward motion of the swing takes 40 frames to complete and at the 20 frame mark Tarzan has just begun to enter the leaves of the canopy. If the large branch is our halfway mark and the canopy leaves stand approximately halfway between the branch and where Tarzan began his swing, than at half of the time of the entire motion he is closer to 2/3rds of the way down-- much further than he would if be the swing were realistic.
This is a movie with a constant investment in believable gravity as the prime visual appeal of Tarzan is his ability to swing effortlessly through the jungle like an ape. Yet, as previously illustrated, in certain moments of heightened action, the audience is willing to forgive certain embellishments if they can increase the excitement of the events. Having Tarzan zip like a torpedo to his destination on the branch a bit more quickly than is realistic may give the impression that he is in control of his motion when he’s in the jungle. Having a bit more air time at the apex of the swing may have been a bit “juicier” of an animated motion, but also could have made it look like Tarzan has a less-than-heightened ability to control his swings.
If film and animation are guilty of violating the rules of gravity as they see fit, games are guilty of entirely denying, freely amending, and publicly embarrassing them. A prime example of how games do this is the action title Ninja Gaiden.
In Ninja Gaiden, the player controls an angry master Ninja who must utilize all of his acrobatic and mystical skills to lay waste to an army of evil Ninjas and demons. Despite what many of the amazing feats Ninjas are capable of performing, the actions seen in the above video are entirely unrealistic. In the case of the multiple mid-air cross slashes (~30s), if one were to ignore the matters of teleportation and spontaneous acceleration, there is still a lack of downward acceleration as a result of gravity. An object in the air will always fall at a constant rate due to gravity regardless of its horizontal speed. Thus, the perfect horizontal slashes made by the hero ninja are--among other things--unrealistic.
Numerous other flairs of this performance also venture beyond simple exaggeration of realistic possibilities. At about 34 seconds into the video we witness a downward slice launch a decapitated head ten feet in the air, which would not happen regardless of the force of the sword strike. At 24 seconds into the video an enemy performs an air kick on the hero which launches him an additional five feet against the direction of gravity, yet the required force to achieve this action in addition to the pull of gravity would’ve launched the offending ninja directly into the ground. In fact, it’s safe to say that just about any action performed in this game that deals with gravity is, in one way or another, inaccurate.
Intentionally stretching the effects of gravity in film or games serves one primary purpose: to entertain. Violating this most commonplace of physical forces is a means by which entertainment media plays with viewers’ perception. Changing gravity can give added strength to a character we’re meant to believe is strong, it can give grace to characters we’re to believe are graceful, it can increase the impact of falling objects and make landings more painful. In the same sense that gravity gets no respect in film and games, it also gets tremendous respect because it is through the careful manipulation of it that an experience can be improved.
A. Introduction
i. Discuss why gravity is so awesome to ignore in movies (falling/flying = cool)
ii. Brief synopsis of *real* gravity (where it comes from) vs. cinematic "gravity" (aka "down")
iii. Hypothesis: Gravity gets no respect in any fictional medium.
B. Live Action: Star Trek
i. Artificial Gravity - Why is there a "down" on the Enterprise (contrast with 2001)
C. Animation: Tarzan
i. One-armed throwing of full grown human females is easy (when Tarzan rescues Jane)
ii. Relatively slow vine swinging and branch sliding = big air.
D. Videogames: Ninja Gaiden
i. suspended air combo attacks, double jumps, wall running, and other ninja-ly thingsE. Conclusion (Gravity is cool, but not as cool as having less of it)
Cartoon Physics in Cloudy With A Chance of Meatballs
The film Cloudy With A Chance of Meatballs takes place in an eccentric world filled with eccentric characters who are constantly, eccentrically, stretching the laws of physics. The inhabitants of Swallow Falls are thin, noodle-y people (or, at least they are at the beginning of the movie) who move very deliberately between poses as they interact with one another and their environments. In fact, everything in this universe occurs with a sense of extremely exaggerated realism where every pose is pushed, every reaction is overacted, and all motion is cranked to the max, all for the sake of comedy. A few key eccentricities of this universe that interest me are the surprising strength of the film's rat birds, the characters' ability to hold unbalanced poses for impossible lengths of time, and their incredible durability in regards to absorbing physical damage.
Really, just don't mess with these guys.
First off is the mysterious strength of the rat birds. Native to swallow falls, the rat bird (Verminus, uh, Bird...us) is a hybrid creature of artificial origin. Created by Flint Lockwood during his inventive teen years, rat birds possess uncanny strength. A single rat bird has the capability to carry off a small child and in groups they are able to lift fully grown men. To understand the flight capability of the rat bird, we must first analyze how bird birds fly. The process of avian flight is more complex than simply rapidly displacing air- it is a series of adapted specializations that come together that ultimately enable flight to occur. Hollow bones, feathers, specialized muscles, and adapted organ systems all play a part in assisting birds to fly, whereas the rat birds in Cloudy only seem to have wings with some feathers. The location of the rat bird's wings on its hips makes comparing its flight capabilities to that of a standard bird even more difficult since real bird's wings are analogous to the forelimbs of mammal with similar anatomy and skeletal structure. However, assuming that rat birds possess all the necessary inner mechanics to manipulate their wings in an analogous manner to their naturally air-bound cousins, there are numerous aspects of how their flight is exhibited in the film that is not physically logical. The first instance of this occurs approximately eight minutes into the film when a lone rat bird kidnaps young Billy. The creature's total screen time is about 1.8 seconds divided evenly between its descent and ascent with the newly acquired child. This information is enough to indicate the laws of physics of have been disobeyed. Observing the size of the rat bird relative to Billy, and assuming that the creature does not have the lightweight skeleton adaptation that normal birds have, I would guess that it weighs somewhere between 16-24oz (1-1.5lbs.), putting it in the same class as the typical barn owl. Because it did not attempt a swooping kidnapping at high speeds which would have offered greater consistent lift to the rat bird since it would have kept air flowing around the airfoil of its wings, and because it instead chose a mostly vertical approach, slowing its descent towards Billy would have taken several times longer and been much less linear than it appeared in the film. After acquiring the extra heft of the young child, generating enough lift to rise back out of the frame would have taken significantly more time and effort than what was witnessed in the short interaction and would certainly have taken a much longer expanse of time than it took for it to descend. (not to mention that a rat bird of that size, flapping its wings at that speed, would not have been able to lift the child in the first place.)
An other instance in this film where rat birds exhibit unnaturally powerful airborne capabilities occurs near the end as they descend from the heavens carrying the hero. This occurs 1 hour and 19 minutes in and the swarm contains about 25-30 rat birds. Despite some of the creatures flying on the outside of the swarm and seemingly serving no purpose in lifting Flint, the relative ease with which the rest of them are able to carry him is in line with their previous exhibition of strength regarding Billy at the beginning of the movie.
Moving on to the non-mutated bipedal characters in Cloudy, the humans in this film-- in certain situations-- exhibit an unnatural ability to maintain unbalanced poses for quite a lengthy period of time. One of the first examples of this occurs 11 minutes and 45 seconds into the movie when Flint Lockwood hides the FLDSMDFR (Flint Lockwood’s Diatonic Super Mutating Dynamic Food Replicator) behind his back while talking to Earl the policeman.
Blue: Base of Support/Green: Line of Gravity/Red: Center of Gravity/ Yellow: Realistic Pose Indicator
While it’s hard to gauge Flint’s exact weight due to the fact that he has the same proportions as a tall noodle, I’m going to assume he’s ~5’8” tall and around 120lbs. We'll estimate the weight of the FLDSMDFR and Steve The Monkey to be somewhere around 30lbs total. Now, at any weight Flint would have to alter his stance to compensate for these items, but at a quarter of his total weight he would have to severely hunch forward in order to position the Center of Gravity back over his Base of Support. Obviously, he can't do this in the shot since the audience has to believe that Earl somehow can't see Flint carrying the device, so the sacrifice of realism is made. In a following close up shot, Flint not only fails to compensate for the weight of the items he's carrying, but he actually leans in the wrong direction, so shooting it in close up may not have only served an aesthetic purpose but also served to hide what would certainly have been a noticeably impossible pose. On the other hand, Earl's Center and Line of Gravity line up nicely with his base of support so his pose is quite believable. In fact, Earl display's a good sense of realistic gravity through the movie. At 1 hour and 7 minutes in, we can see him running away from a food-alanche while carrying a grilled cheese sailboat. Even though he's holding the boat above his head near the rear, the weight of his wife and child along with the pizza sail being above him instead of the swiss cheese sail combine to help keep it realistically balanced above him. Furthermore, since he is running with boat, if the Center of Gravity is still assumed to be somewhat in front of his hands and feet, his consistent forward momentum would be preventing it from falling thus making the pose more believable.
One final feature of the Cloudy universe that cements its physical laws firmly within the cartoon realm instead of realism is the durability of its characters in regards to concussive impact. This is repeatedly witnessed during the ice cream snow day scene. For instance, in one shot Earl and his son Calvin go sledding from a rooftop directly into a dumpster, which Earl hits firmly with his gut.
(...)
It takes Earl about 8 frames-- 1/3rd of a second-- to travel from the roof to the dumpster. If we were to assume that the rooftop sits at a height of 10ft and the part of the dumpster that stops Earl hits is 4ft high, then that's a 6ft drop in a third of a second. This converts to slightly less than 13mph since fast motions are often slowed in animation so that the viewer can see the action. Nevertheless, an impact at that speed to the gut would have taken a normal human quite a bit longer to recover from than it took Earl. This, however, perhaps is not as much a testimony towards the unrealistic nature of the film as it is towards the manly-manliness of Earl.
Moments after this shot, we see another case of extreme impact with little damage done when Flint engages in his first snow ball fight. With much enthusiasm, Flint discovers the joy of throwing snowballs and hits numerous little children with these high velocity projectiles.
In the first shot of this, he is able to hurl a snowball at Cal from 6ft away and hit him two frames later. This would put the snowball at almost 50mph. Understandably, Cal goes flying. However, he is heard laughing as he is pelted with the delicious, high velocity projectile. In fact, most of the victims of Flint's enthusiasm are shown with a smile on their faces moments after receiving an icey snowball in the face.
What does it all mean?
These are but a few examples of situations where the animators of Cloudy With a Chance of Meatballs took liberties in their handling of physical laws. Yet, if the viewer analyzes each situation, they'll come to notice that it is never done without purpose. The malleability of these laws in an animated universe is one of the benefits of working in the medium of animation and when an animator understands how objects behave physically in reality they are able to competently push those same objects in a fictional environment to create better films.
