“Perhaps nothing is so fraught with significance as the human hand.” — Jane Addams, Writer/Sociologist
Arms and hands are important. But despite working with their hands all day, most artists are frightened about drawing or animating arms and hands. The reason lies in the artist’s unwillingness to understand them in its entirety.
The arms and hands are — and we’re talking particularly about the human form rather than the animal one which is more genus specific — a microcosm of both the simplicity and complexity of the entire body. One has to see the whole but also understand the parts and how they all go together. And like the body, the upper limbs are both a form and an action, meaning that it’s a solid structure that carries not only weight but also function, and mostly notably by extending psychological expression through gesture.
Here are a few things to take note of when incorporating arm and hand work in your art or animation:
a) Know the basic anatomy
Every artist should spend some time studying and understanding the basic structure of the limb and all its details. Know what and where those parts are and what they generally look like. Not that we have to able to identify all the scientific names or be able to duplicate it perfectly in rendered form, but we should have a basic yet solid idea of its substance and appearance. At least as much so that we can recognize the forms when we see them, either in life and in video/photo reference. We can’t duplicate or create what we don’t know or can’t see.
b) Know the mechanics
If we don’t know what the scapula or collar bones do, or how the shoulder muscles such as the trapezius and deltoid muscles work together with the pectoral muscles to move the arms, then we don’t know much about how arms work. For example, study the muscle insertion points and one can see that the one branch of the chest muscles is attached to the humerus bone, and hence we can’t move the arm without effecting the look and shape of the chest. The various joints of the arm, on the other hand, also vary from one connection point to another, from ball joint, to lever and again to ball joint. This leads to the strange way the arms moves as it turns, swings, pushes or pulls. The shoulders in general, are often misunderstood and are both commonly under-animated or animated incorrectly. The shoulder joint is both a translation and rotation axis, the apparatus moves up/down/forward/back and rotates up/down/in/out as it floats on top of the ribcage, while the top of the humerus which lies in its socket rotates in near 180 degree action (half sphere). The largest and strongest muscle is the trapezius, a trapezoidal shape which makes up a group of muscle fibres extending from the top of the neck spine, out towards the tips of the shoulders, and down to the lower middle back. It is the most important group of muscles for shoulder/arm action.
c) Understand Pronation and Supination
The arm apparatus has its tendencies and preferences in how it wants to move. But because of the complex adjunction of the various components — scapula to humerus (upper arm), humerus to ulna/radius (lower arm), lower arm to hands etcetera — the arms create torque and power by how it rotates and bends. Pronation — when the arm turns over like when we look at our watch or twist open a jar — is primarily a closing gesture, where the hand turns inwards closer to the centreline of body and the elbow points away from the ribs. Supination — when the arm flips outward like when we ask for change or deal out a deck of cards — is primarily an opening gesture, where the hand turns outwards away from the body and the elbow points into the ribs. Animals such as horses or dogs have their elbows anatomically aligned and constrained close to their rib cages, unlike primate forms whose elbows (and thus arms) are completely free from the body. If you understand the anatomy, you’ll know that the radius bone which is closer to the thumb crosses over the ulna bone in pronation and we see the top of the hand. This is also the position that causes carpel tunnel syndrome which many animators are familiar and one can easily see why (the inbetween space for the artery and the nerves that service the hand become compressed). The point is, the way the hand moves and looks is heavily determined by shoulder and upper arm positioning and action. There is so much more to arm action than mere pendulum motion.
d) Understand the movement as a unit
Arms can move in fantastic fashion from lifting, pulling, punching, slapping, to baseball throws. Arm action can be both bold and powerful or tender and articulate. The animation/artist must be judicious in his vision of how to use/express the hands in motion. But he must first understand how it works as a unit. Arms in passive action can behave like a pendulum. They can twist and turn like driving a car (known as pronation and supination as explained above) and also swing in near full 360 degree vertical motion like a turbine. Certain actions generate move power, others more control. Hence the incredible and powerful diversity of the hand so it’s no wonder they say that the human hand’s uniqueness may have been as important to our evolution as a species as our brain. But the most important aspect of the movement of arms for animators is the concept of “successive breakage of joints” which really follows from the principle of lead and follow. The shoulders drive the upper arms which drive the lower arms, which combine to drive the rotation of the wrists and in turn the thumbs and fingers. The parts of the arm do not operate in isolation. Richard Williams’ excellent book The Animator’s Survival Kit goes into significant detail in this regard. I will not duplicate such information here. If you don’t understand how we build torque or force in the arms, I highly suggest studying those pages seriously as well as observing video at various camera angles.
e) Simplify the Forms
In art we make use of symbols — lines, shapes, colours — and how they move to express our ideas. Since realistic anatomy is complex and rarely to be duplicated in detail except in the case of special effects work, artists must simplify the structural parts. Art is, after all, not duplication but creation. Here, we have leeway to exaggerate or caricature the form and its movement. The best thing is to see the parts as a mixture of solids connected to each other, then we understand where the movement begins. It also helps to set standards as to where to push things like squash and stretch that make more sense and have greater believability and appeal. For example, stretching the neck makes a lot more sense than stretching the more solid form of the skull (super cartoony animation notwithstanding).
f) See the Groupings
When we begin to study anatomy and body mechanics, we begin to see groupings both functionally and artistically. That is, certain things go together. The right and left arms, for instance, influence each other because of the connection to the pectoral (chest) muscles and the trapezius, creating a rubber band-like connection. The same goes with things like hands. The thumbs tend to work with the index finger and the remaining fingers tend to curl and uncurl together in a group. Astute artists throughout history have well understood this and documented it in their work. As animators we must truly understand both the way the hands are constructed and how they move with the rest of the arm. Only then will it look right and feel right. Study of our own hands helps us see how they move and how it looks in any action. Fingers and hands twist, turn, open and close in a very specific fashion. For example, we always close our hands with the shorter fingers first and open our hands leading with the thumbs and index finger. Test it out yourself. Remember: respect for the structure and mechanics is often rewarded with both beauty and believability, especially when given extra flair and exaggeration in the right spots.
g) Look, Touch and Draw
If we don’t spend anytime to “experience” hand and arms, we’ll never learn about them fully. Without direct observation, tactile exploration and tangible study of the arms and hands, an artist will never develop comfort with them. Weak hand animation is so prominent in animation today it’s hard to witness — we see mechanical, weightless and even rigid spatula or “box” (closed fist) hands everywhere. It’s so unfortunate since arms and hands have been and continue to be a HUGE part of human expression; hands are beautiful. And while a lot of that has to do with more and more animators mindlessly dependent on copying their video reference, even more of it has to do with not being aware of what we are seeing or understanding what’s happening in the action, and ultimately not implementing any sense of design and creativity with the work. And the easiest way to remedy this is by drawing. Drawing teaches attentive observation and creative design. Go and build a fuller understanding and greater respect of this very important limb because it is, after all, what enables us to make art in the first place. Our human hands really are “thinking hands.”
“The hand is the visible part of the brain.”― Immanuel Kant, Philosopher
