Anim-blog 2: physics

Imitating physics requires a full comprehension and investigation into the nature of movement. As humans we are extremely observant and can recognise the artificiality of animated movement. To trick the viewer animators must analyze and stratify each of the competing factors in movement to make their models appear life-like and convincing and to fully immerse the viewer in the world created for them. In recent decades several techniques have emerged to master this illusion. Understanding the technicalities of these methods helps to foster a deeper appreciation of the artform and to reveal the trick behind the magic.

Timing is a crucial factor in creating realistic physics. Over time it has become obvious that while movements that are closer together require the animation to slow movements that are further apart require a more rapid progression of adjustments. That is to say, when small, subtle movements are captured in rapid succession it is essential that the frame rate is extended so that the complexity of a sequence is matched by the fluidity of its simpler counterparts. Imagine a model pushing itself off the floor. As the character places their hands on the floor, stretches their fingers and arcs their back while moving a foot up to lever themselves up many movements are happening simultaneously. When the character reaches a crouching position the movement simplifies, allowing the animator to characterise the movement as shorter but equally fluid. It is essential to understand variations in movement and to observe the subtleties to give character to the puppets. A handshake has great relevance in our society and therefore a timid and slow movement will contrast greatly against an enthusiastic one. Here it is important to state the secret behind articulating these micro expressions. Animators must pace each stage of their actions in the form f a mental storyboard and recognise the scale of the actions when set alongside one another. Pausing a character’s movement for up to 6 frames can make the difference between a gentle pat on the back and a cautious pat on the back to create the impression of a thought process.

Coming to terms with the principle of motion arcs is the most important step in creating natural movement. Understanding that movements are not linear and do not always progress in a straight line compliments any other more technical tool in an animator’s toolkit. Often the most complicated movement appears to be the simplest. Making a character walk realistically requires attention to detail and that each frame registers as a smooth transition. This can be achieved through a tool known as onion skin layering. This technique allows the animator to capture a frame and then creates a live layering of that frame over the adjustments made to the models. Onion skin layering helps to give the animator a visual aid and helps the arc of movement to follow the imagined course, switching at the correct frame to a new course of action or fostering the interaction of two variables. Imagine, for example, an acrobat landing a sequence of movements. Understanding how the weight of the body influences the speed of their descent and the pressure of their movement in a way that is tailored to the circumstances simplifies a complicated animation sequence greatly. Often times an animation studio will seek to hire animators with a background in physics, biology and art so that the animator can use their accumulated knowledge from muscle groups in the human body to the mathematics of the exertion of force on objects of different elasticity and weight.

Actions often overlap in animation and this can complicate things. The way to resolve this is to stagger actions into mathematical sequences. If an animator was animating a model playing the piano while moving it’s head they could calculate the sequence of repetitions of movement for each of the three components: the head, the right arm and the left. Therefore the animator can begin with the right arm and begin an animation arc and calculate in the frame delay when the next component will be added and course altered to strategise a complex movement intelligently. In Kubo and the Two Strings there is a scene where Kubo and his band of misfits must come up against a cave dwelling giant skeleton. In this sequence many of the characters appear in the frame simultaneously acting individually so that their movement loops interact. To overcome the difficulties of this process Laika employed a team of animators who could comprehend the syncing of movements through stagnation. They identified a particular movement angle in one character as a red flag to the adjustment of the movement arc of another.  the sync is real people.

Perhaps my favourite animation technique is the face replace. In this technique each model is given thousands of replaceable facial components which are replaced as the character speaks or reveals an expression. The face is usually comprised of a replaceable cheeks, brows and eyes component and a separate mouth and chin expression component which come together to give a full spectrum of expressions and facial shapes much in the same way our faces alter themselves. Laika use 3D printing in their facial reconstruction using up to 200,000 components for each character as seen in The Boxtrolls. Keeping in mind these faces must link together and bridge realistically as well as the fact that different characters have different shapes and muscle/fat groups this is no small task and requires careful planning. To do this each facial expression will have a title and phonetic symbol to articulate it’s purpose. This gives the impression of muscles and therefore the physicality of a face.

Rigging and armature are the two most important instruments in creating support and flexibility in the articulation of poorly balanced or air-bound movements. An armature is the model equivalent of a skeleton. It provides a structure to build the model around mirroring the joint movements and flexibility of each element down to the eye sockets. Using a combination of ball bearings, steel and joints the armature is designed to provide the same level of flexibility as the designed character. Rigging allows the animator to create mid air shots and often works in conjunction with the armature in the form of a metal arm to suspend the model. Furthermore, the rigging helps to balance models mid-movement when they are unable to support their own weight. This rigging is edited out later to give the illusion of physics. The tracking shots and rigging to capture the movement of the models is enhanced by a mechanical system which moves in conjunction with the scale of the model’s movement. Moreover, this rigging can flip the camera for closer high quality shots.

No level of research can come close to recording the physical action that the animator is trying to imitate. To do this the animator should record each of the actions components individually and avoid acting out the entire scene. Repeating this process time and again to mark the transition between movements gives the animator a visual guide of the attempted output. Ensuring that the actor has the right body type is essential in masking the illusion of movement. Clothing and hair are often the most difficult components to animate and maintain. Finding the balance between flexibility of these components and the avoidance of unintended movement requires careful and meticulous precision. The Wes Anderson film Fantastic Mr.Fox included realistic fur and feathers in the vast majority of its puppets and demanded a full range of movements. To ensure that fabric moves realistically, flexibly and with decided intention. a plastic glue like substance covers the material to make it more resistant to pressure and more durable for added consistency. This only covers half of the process however. Many production companies employ live action costume designers to create the costume on a larger scale so that thousands of small footage tests for each component can be observed under different wind conditions and movements. Therefore the material will articulate real movement as opposed to the imagined progression of movement. Often the storyboard part of the process helps to slim down these tests considerably.

One must understand that the current animation techniques have extended to the movement of the environment. As a recent and evolving artform, animation is still pioneering new techniques. One of the greatest challenges to stop motion animation is creating the illusion of weather and the movement of debris. In Paranorman there is a scene in the second act in which the zombies rise out of the ground. Dirt and debris spray everywhere as they emerge from the soil. To achieve this Laika created individual wires attached to individual pieces of rock and dirt which would separate and drop individually. This of course also required a series of live-action tests which were mirrored and articulated. Four years before this a more impressive feat was achieved – rain. In Wallace and Gromit A Matter of Loaf and Death Gromit makes his way to the door of a mansion while it rains, shakes his head and steps inside. To achieve this animator Jo Fenton had to suspend each of the individual rain droplets and move them individually. The rain droplets was  made out of hot glue which allowed her to shape the droplets in a way that interacted with Gromit and alter their shape in instances such as when Gromit shakes the droplets off.

Any attempt at fully exploring the technicalities of this highly technical and practical artform fall short at the wide range of implements, tools and comprehension necessary in creating an imitation of physics – the laws of the universe that bind us together.



Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s