Reverse Video Reference of Walking

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The Laws of Physics in an Animation Universe

The Physics of Chicken Run

The world of animation has always been a place where we could easily escape to and get away from the problems that plague real life or simply for entertainment. But among CG and 2D films, none does it quite as well as Nick Park, the creator of the feature claymation Chicken Run. Flawless as it may seem, though, Chicken Run has its own share of physics faults. It is these faults that I would like to address in this essay.

             For example, we see that the gravity on Mrs. Tweedy’s farm is the same as in our own world; the reaction, however, is not equal to the action when characters push things around; and the faster movements, such as running and flying, are also kept inconsistent with the number of frames they would normally take up. The counter theory is that in order to push the contrast between the human world and the chicken world, the laws are a little bent whenever the chickens are interacting; that is why we also see ridiculously outstretched reactions happening with minimal applied force, as well as slow-motion style jumps and flying. In a word, the film’s established action and reaction principles contradict themselves when necessary.

            Throughout the majority of the film, we primarily see dialogue and the characters walking at a relatively even pace, which is not enough to give us a clear idea of the gravitational forces behind the scenes. Going chronologically, throughout the opening credits we notice things that would lead us to believe that the gravity works the same as in our world: for instance, the farmer throwing Ginger, the main chicken character, into the abandoned coop; Ginger being pulled on a wheelie in a dark tunnel; and at the end of the sequence, the farmer nudges Ginger on the back, making her stumble and fall over. Other hardly noticeable factors include the leaf of paper falling in a typical downwards arc after Rocky the Rooster’s initial entrance. Yet whereas the animators could actually use real paper to achieve this, the real artistry is seen at the end of the first flight training sequence, when the clay feathers float in the air, making the viewer forget their abnormal thickness and mass. On the opposite end, we see the challenge of representing heavy objects, such as when the truck pulls up to the house the second time, carrying heavy machinery: here, the settle becomes really noticeable; we see the truck’s frame rise up and then fall softly on the wheels above as it comes to a stop. Finally, the climatic moment offers a great number of examples of appropriate gravitational pull with eggs being hurtled to the ground and characters nearly falling out of the flying apparatus in the process.

            While these might be unextraordinary examples, they become significant factors in suspending our disbelief when coincided with unrealistic representations of fast action. The few major scenes in Chicken Run are enough to convince us that its makers breached a bit too far into slow motion for the flying to be believable; therefore, it’s safe to say that there are too many frames per second in every flying sequence than need to be, making the laws of flight different from our own. To use one of the above examples, Rocky’s first flight into the farm holds our attention for approximately ten seconds from when we see him in the distance to his crash landing into the wind vane. It is slow enough for the rooster to wave as he passes by the chicken standing on the ground, so one begins to wonder if it is in fact a flying bird or a projectiled one. The crash convinces us of the latter, and later on in the story it is confirmed that Rocky is a circus bird shot out of a cannon. If we estimate the distance relayed to us from the farm to the location of the cannon, it is about a mile away. Without speculating further into the impossibility of the bird’s survival from such a violent outburst, or at least the prospect of it’s keeping all its feathers, we can estimate that the cannon’s angle is somewhere between 35º- 45º. Given the total flight time (t), it is easy to figure out the velocity (v) by plugging in the gravitational acceleration (g = 32.2 ft/ss, standard on Earth). Therefore:

2V= g x t   or  v= (g x t)/2

This gives us :

v = (32.2 x 10)/2

v= 161 ft/ss 

Or in miles: 161 ft/1 sec = 5,280 ft / 3600 ss   gives us 109.7 mi/hr.

The bird itself is about 1 foot high, as we can clearly see when the chickens surround the farmer. Given the acceleration chart, we can figure out that in order to travel over a hundred miles per hour would take between 75 and 85 inches per frame, which clearly is not happening; Rocky is traveling approximately the length of his body (12 or so inches), making the velocity only under 20 mph. Given all these factors, it is both impossible for Rocky to travel that slow from a cannon only a mile away, or if it is in fact slow motion specifically there for effect, it would be impossible for him to travel over a 100 mph and suspend himself enough to wave. And since it does not look like slow motion, there are evidently too many frames in order for the flight to read as it would in life.

            The same is true of the finale, where we see Ginger battling Mrs. Tweedy on a twinkle light wire suspended from the flying crate. Again, the possibility of realistic lift off is impossible both in terms of the flying machine’s velocity and weight, and the background behind Mrs. Tweedy. The first is prone to suspicion given the fact that it would take an apparatus of that size a much greater speed in order to get sufficient lift, much less to hold up while being weighed down by a human being. Second, we see that Mrs. Tweedy’s head, which cannot be bigger than 20 inches, is moving at a rate of 13 to 15 inches per frame, making the velocity no more than 25 mph. Either the birds’ plane is too slow, making its flight impossible, or the frame rate is wrong.

            The third on the list of oddities is the entire correlation between action and reaction in this movie. Undeniably, some motions are flawlessly executed, such as the tennis ball bouncing off the wall as Ginger waits to get out of confinement. For the most part we see that in this world the reaction is not always equal to the action. The toy catapult throws a turnip some dozen feet across the room in only two seconds. Given the arm’s tangential speed, the throw would be instantaneous and not take as long to reach its target. Plenty of comedic examples of the same nature occur during the first flight training episode. A chicken strapped to a box is thrust forward with the help of a stretchy band only to fly forward when the box stops abruptly, proceeding to bounce off the fence at the same speed as she flew into it. While the inertia might make sense, in this case the kinetic force would not be bounced off the fence but instead be absorbed into it. Approaching the end, we see Ginger’s attack on the farmer as he opens the chicken coop; she is able to gain his face almost without crouching, standing five feet below. That kind of jump would normally require at least twice the crouch time and magnification.

            A competing theory might state that these incongruities are seen only when chickens are interacting, therefore, the world of chickens has a different set of reaction laws from that of people based on size, etc. It is true that in the world which the Tweedies inhabit things go a lot more smoothly: we even see the Niquist effect when Mrs. Tweedy spins one of the round blades from the pie maker. However, there is no physical mix up when the chickens and humans are interacting. In fact, this theory does not work because the chicken’s size does not make any difference when it comes to reaction timing; moreover, we see that such exaggerations only occur in climatic points of the story, where outstretched comedy furthers the story. We see humans and birds act similarly side by side, as when Mr. Tweedy is fixing the pie-maker and the chickens are building their plane; nails are pulled from boxes with natural force, fabric cut, gadgets spun at appropriate timing. In the dance scene, the same force applied to produce unreal spins does not have the same effect.

            In conclusion, we get a clearer idea of what a claymation universe consists of and what elements it retains. The gravity might make things believable, yet other principles are subject to alteration. Yet no matter how simple or complex, every action goes toward progressing the story line, therefore is filled with meaning. It is at that point that perfect timing becomes questioned when the perfect outcome of a scene is at stake. Yet when both find a way to blend in a smart and funny way, that is what makes a classic, as Chicken Run deserves to be.

 

 

Outline for the First Term Paper

In this essay, I will be talking about the physical laws in Chicken Run. As a claymation, it has the best of both worlds: the appearance of reality (since most of the props are real, besides the sculpted characters) and the cartoony feel of animation, which makes for great entertainment.

But which parts are exaggerated for entertainment and which are stretched for the sake of storytelling and animators’ convenience? In this particular feature, where the world of chickens exists side by side with the world of humans, the scenes that obey the factual laws and those that are “tweaked” are intermixed for proper affect.

            First, the laws of gravity are the same as in the real world. We see many examples of it by seeing the farmer and his wife going through the motions much the same way as we would expect any human actors on screen. The car pulling up, heavy machinery falling, resistance when handling heavy objects as opposed to light ones – all show that there is a gravitation pull.

            Second, we see that the reaction is always equal to the action. Things fall down naturally, characters collide when pushed around, etc. (Examples: around the chicken feed, defending against the farmer, building the flying machine - hammering nails, cutting fabric, handling tools, etc)

This established law is broken in more than one scene, primarily for entertainment value and the pacing of the action. For example, several catapult scenes, exaggerated flops, spins, kicks, etc. Some things come too hard, others are too easy.

Third, the flying principle follows the normal number of frames. When objects are tossed around, when characters are thrown through the air, and the final flying machine sequence, all display the eye’s natural perception of flying on screen.

This law is broken as well in a few scenes that emphasize the importance of that moment in the story. There, either the character or the background slows down to a fairly readable rate, where the viewer can easily perceive the action. (Examples include Rockies first entrance, Ginger and Mrs Tweedy hanging by the rope in the end, and a number of small scenes.)

Overall, both following the scientific principles and overlooking them creates a great visual!

 

Stop Motion Animation of Falling

This is my first time doing a stop motion animation, though I am quite experienced in the traditional 2D. And even though there is no drawing or technical skill involved, this was still harder than I thought and did not come out to my liking even aftr several hours of tweeking. To create the bounce effect, I marked the floor for each stage of falling a la Chai, removing the second 1/2 division. Overall, it seemed to work...