Wednesday, November 23, 2016

Equine Anatomy and Biomechanics: A Primer of Equine Engineering for Advanced Students Part XV, Physics


Welcome back to this 17-part series that explores equine anatomy in a bit more depth than Anatomy 101, which was designed for beginners. We can therefore think of this series as one for the intermediate student since there's more to it than discussed, which is keeps us learning. 

In this installment, we'll discuss physics as it relates to our clay. But what is physics in this regard? Is it the workmanship that goes into the construction of our sculpture? No, not really. Does it pertain to the materials we've used in its creation? Nope. Is it how our sculpture is designed from an artistic perspective? Kinda. Actually, what it relates to is how the natural laws of our physical world are expressed in the design of our sculpture...what forces would a real horse undergo in the real world and how are they expressed in our piece? Are they accurate to life or made up? Are they overlooked? Are they consistent throughout the body? Do they further the narrative or impede it?

It's not enough to simply sculpt his body accurately, in every conceivable detail. Unless we instill the natural laws that govern his existence, our sculpture simply won't come across as very convincing despite anything else that may be accurate. The horse doesn't exist in a "reality vacuum" and so neither should our sculpture.

So let's get to it!...

The Physical Forces

The horse is a living, breathing animal and not a simple, artificial abstraction. The animal is movement personified, with motion that's living, fluid, changing, often shifting and spontaneous, and always thrilling. Imbued with life, energy, power, and "spark," equine motion is irresistible to be sure. It's important then to be aware of these qualities in order to express them in our sculpture accurately and dynamically, and we do so in part by infusing the physical world into our clay.

To that end, the forces affecting equine motion can be broken down into thirteen basic factors: mass, balance, momentum (with inertia), centrifugal force, impulsion, tension (with tork), chaos, "bounce," "slump," "snap," "float," "kick up," and natural coordination.
  1. Mass: Horses are a bulk of bone and flesh subject to the effects of gravity. Mass should therefore be imparted in the body through indications of shock absorption, muscle exertion, and the sculpture's posture to best impart the impression of the effort required to move or position such mass. For example, mass can be expressed through the flexion of the fetlocks during impulsion or weight-bearing, or the effort expressed in the muscles such as increased definition, 3D pooching, or muscle striations. Even the exertion depicted in the spine's posture helps the idea along. Expression can even be used to denote the effort required to move himself forcefully. It takes a great deal of power and coordination to move such a large herbivore, and our sculptures do best when conveying it.
  2. Balance: Horses are constantly adjusting their balance, with their skeletons and muscles making accompanying adjustments which can change the posture and body alignments, sometimes rather radically. For instance, when one hindleg is square under the body while the other is drawn backwards, the pelvis will often tip down on that leg as it "follows the leg to the ground." Another example is when his neck is cranked sharply to one side, so he's looking behind himself, the front aspect of his thoracic column with often bend along the curve as that side "pooches out." Other examples are "tracking down the middle," "barrel swing," and "body snaking." “Tracking down the middle" is how horses tend to naturally move; they usually place their hooves towards the median, especially at speed. That's to say, horses typically don't place their hooves directly straight down, but slightly, and sometimes markedly, towards the median. This isn't to be confused with moving crooked. As for "barrel swing," that's when the forces of movement and balance swing the barrel over the supporting hindleg, like a pendulum. The effect can be clearly seen or subtle, but is a natural function of shifting weight and mass. This is referred to as "schwung" in German. Remember, there's a huge weight of viscera inside the animal's torso, and it sloshes around. So a horse moving naturally with a relaxed body will have barrel swing whereas a horse with a tense body won't as much. Now regarding "body snaking," that occurs when the horse curves his body in resonance with motion to aid balance and compensate for the force of the motion. For example, when a walking horse, when seen from above, will undulate his spine to alternately bring one side of his pelvis forward with each hindleg step forwards. In addition, when standing, the horse is constantly adjusting his balance, and so may lean, or move his shoulders, neck, or hips, even his pasterns, to accommodate. A standing horse doesn't just stand "straight up," but exhibits all these small corrections constantly. Therefore, our "standing" sculpture is brought to life when we imbue it with these ongoing movements.
  3. Momentum (with Inertia): With all that mass moving around, momentum (and inertia) becomes a significant factor for movement. It distorts the flesh and can create wobbling, jiggling effects in loose or relaxed body parts, or it can cause tension and stress in activated body parts. In addition, momentum (and inertia) affects joints and other body aspects as often seen with wobbling hooves or ears (often seen on mules with their wibbly-wobbly ears). Momentum also propels the animal forwards as he pole-vaults over his forelimbs, an important quality to capture in clay. We have to get the sense that our sculpture is moving in a way that it would take power to cease or turn it. Momentum and inertia play a big part in how we design the mane, tail, and feathers, too, since they're passive aspects at the mercy of physics. For instance, perhaps we created a sliding stop sculpture. To drive home the idea of an instantaneous stop of momentum, we can have the mane still "catching up" to the stop by having its tips still oriented backwards rather than all of it swooshed forwards. Or maybe the long, silky feathers on our sculpted feet show parts and flowing bits in synch with how the leg is being moved. Indeed, hairy bits can go far in helping along this aspect of physics.
  4. Centrifugal Force: Associated with momentum, it entails momentum in a spin. For instance, such things can include a lifted front hoof that's flung laterally outward in a sharp turn, or how genitalia, lips, ears, loose skin, hair, and relaxed muscles are pushed outward in a spinning or abruptly turning horse. Or perhaps his spine is curved into a turn and his barrel is markedly swung to the outside of that turn. Maybe his muscles are more tense on the outside of the turn than they are on the inside of it. And again, the mane, tail, and feathers can do much for conveying this feature. Truly, every time the horse turns, pivots, or spins, he's subject to centrifugal force and adding small indications in how his flesh and hair reacts help to plant our sculpture in a real universe. What's more, horses lean in motion a lot more than people realize such as around turns. The lean can be slight, or it can be pronounced, depending on the speed and angle of the turn. Horses don't just move up and down, keeping their bodies perpendicular to the ground at all times...they lean!
  5. Impulsion: The original meaning of "impulsion" wasn't forwards movement, but upwards movement, such as we see with the lightness of self-carriage, or how the legs cause the body to "sproing up" with lightness. We can help along this idea with posture and through the strategic relaxations of the legs and body, even the wobbling of the ears and jiggly bits of the body such as the "plumbing" in the groin area, the underline of the neck, and relaxed aspects of the bodywaz. Plus, the mane, tail (and feathers) are very useful to forward this concept as they try to "catch up" with the upwards and downwards motion of every stride.
  6. Tension: As muscles are activate they tense up, as they deactivated they relax. We can really amplify (and duplicate) the look of effort then by showing tension in those muscles that would be working and relaxing those that wouldn't be. For instance, tensing the triceps on a supporting foreleg while relaxing the triceps on a lifted foreleg at the trot. This also relates to tork, or the forces that "gear up" or "gear down" the animal's efforts. If we're able to catch how the body braces itself when it slows down or when it compresses in certain circumstances, such as a tight turn, we're that much closer to a faithful duplication of equine motion.
  7. Chaos: This term applies to everything that just happens; that moment when things just occur and react. Maybe the horse has heard something and flicked an ear, maybe the breeze has brushed his mane a certain way, maybe he's excited about something and chomps on the bit, or perhaps his mood lends him to laziness, or perhaps he's momentarily tensed an area of the body, changing his posture or balance. Chaos happens all the time in a myriad different ways, so look for it and consider those touches for sculpture. Plus, being passive, the mane, tail and feathers are also elements of chaos as they're whipped around by the forces they undergo. Don't be afraid to design "wildly" moving hairy bits! And that even includes a hairy coat because perhaps a breeze has caused a section of his winter coat to part and billow. There are lots of little touches.
  8. Bounce: Horses have springy motion, thanks to their many systems that give them agility and lightness to their movements. They essentially move as a series of different kinds of "bounces." For this reason, our sculpture should appear to have that same quality and not appear overly weighted down (unless that's our intention). There should be a freedom in our sculpture's movement, a kind of energy that helps to explain how such a heavy, large herbivore could move so gracefully and lively. For example, we can help this along is through posture with strategic areas being stressed and others relaxed, such as a weighted hindquarter and a relaxed, free forehand. Or how we express musculature's definition over various areas of the stressed or relaxed areas can help this idea along, too. There are many options once we start looking for these things in field study. 
  9. Slump: Sometimes horses are lazy or exhausted, and so move in a distinct way that's plodding, or slumped. 
  10. Snap: Equine motion is quick and often "flighty," for lack of a better word. Hooves can snap into flexion or snap forwards in extension, tails can be snapped into curious curves as the tailbone is flitted around, heads can be snapped up and down with their lips flipping up and down, or heads can be tossed from side to side, or ears can be snapped forwards in alert attention. Capturing the quickness and abruptness of equine motion can go far in bringing out sculpture to life.
  11. Float: The animal's movement is graceful, often appearing as though he's floating along such as with a trot with a long suspension phase. How we design the body and place the legs can go far in mimicking this effect, with beautiful results. For example, in the suspension phase, placing the legs a little bit farther apart with snappy hooves, and sometimes those peculiar braced shoulders we often seen in this motion, can do much to forward this idea.
  12. Kick Up: Remember there's more to motion than just his body, in particular his feet. There's the ground, too! Because of this, if on a base, if we can indicate the force of his impact with the ground through thrown dirt, "fans" of sand or snow, torn turf, tousled or stomped grass, shoved-aside pebbles, thrown rocks, and perhaps even previous hoof prints, we've captured a unique "detail of the moment." Sometimes these features can even be used as supports to further along the idea of the motion rather than stopping it such as a clear perpendicular rod often does.
  13. Natural Coordination: Horses move in ways that express the natural orientations or postures their blueprint adopts when standing or in motion. They relate to all these factors, incorporating them all. Field study is a great way to learn them, as is the astute study of reference photos (when you know what to look for, many of these orientations become obvious). For example, horses tend to keep their heads perpendicular to the ground, when seen from the front, even when leaning or turning. Or the torso will "see-saw" up and down, when seen from the side, based on how far out from under the body the forelegs or hindlegs are. What's more, their tails often express what their spine is doing; if curving around a turn, they tend to hold their tails in line with that curve. Or, for example, when a horse is about to turn on his forehand, say to turn left, he tends to lean his forequarter in that direction, into the turn. More still, when seen from the top, the pelvis rocks from one side to another, bending the spine thusly, at the walk when each hindleg is alternately brought forward under the body in the landing phase of the gait. Even more, when the neck is raised high, the spine tends to hollow out in the thoracic span, causing more a dip in that section. And finally, when coming to a stop, the horse will naturally engage his LS-joint and curl his spine to curl his hindquarter to plant those hindlegs under the body. When he spins from that stop, he'll rock back onto those hindlegs and swerve his forequarter in the direction of the turn, leading with his head. These are just some of the natural coodinations to look for, so pay attention to how horses move under natural conditions.
Artistic Aspects to Consider about Physics

Awareness of physics for our clay is a learned skill. When we sculpt from anatomy charts and focus on structure, type, color, posture, and the other everyday aspects that go into our craft, it's easy to overlook the physical forces that influence all that. The bend of a fetlock, the wobble of flesh, the flinging of the mane, the weight visited onto a hindlimb, and the posture of the animal can all escape us if we aren't paying close attention.

And physics aren't just expressed in the joints and the mane and tail, but the entire body from the posture to the expression, so we need to be aware of that as well. The entire being and body of the animal participates, including his emotions, and learning to see how it does gives us more information to inject into our clay.

Common Artistic Faults With Physics

Sculpture often lacks immediacy and "moment" in their motion, and so appear static and rigid, and artificial. Yet equines are defined by dynamic, fluid, energetic motion and postures...these are large herbivores moving at great speed and energy with tremendous agility and power, or they're bearing weight in constantly changing balance. Unless our sculpture can convey these qualities, it'll continue to appear as an inert tabletop model rather than a depiction of a living, breathing animal living in the real world. Our sculptures need that "inner energy," that "spark of movement." We do this by paying attention to and infusing all those little touches that drive the "feel" home regarding motion. Every little thing counts.

Horses do a lot of leaning in motion, especially around turns, even standing as balance shifts and posture changes. It's a mistake to always orient our sculptures up and down, especially when depicting motion and turning. On a side note, n the top photo, notice that the hock's calcaneum creates a distinct bulge, not being the same width as the back of the cannon or the Achilles Heel?

On the other hand, we can have a preponderance of physical expression to the point where it "stops" the motion, too. Equine motion is elastic so if we convey too much weight and gravity, our depicted gaits won't appear very light and energetic, but weighted down and plodding. It's a delicate balance. For instance, during the extension phase of the gallop, when one foreleg is planted on the ground and placed in a straight upright position, perpendicular to the ground. This design can "stop" the sense of forward motion by "rooting" the sculpting too strongly to the base. Instead, it's often a better idea to make that planted foreleg oriented a bit forwards or backwards to keep the sculpture visually "moving forwards."

Similarly, we should be careful how we design supports or bases. Many times clear rods or how the sculpture is attached to a base will "stop" the sense of motion, too. Instead, a more integrated or different approach could have helped that visual along better. For instance, perhaps placing the clear rod at an angle to trail the motion, or putting flourishes of kicked up dirt under the hooves as supports could prove better options. When we design a sculpture that really conveys the sense of motion beautifully, it's a shame to "stop" that motion with a poorly conceived support system.

Conclusion to Part XV 

Now that we've discussed all these topics and how they relate to realistic equine sculpture, we can begin to process it all together. It's a lot to take in, isn't it? And this is just a start! There's always something new to learn, so approach all this in that spirit and keep moving forwards.

Nonetheless, in the next and final installment, we'll take a look at some myths regarding these subjects so we can learn to filter through them for our work. So much about being a responsible equine artist is about being a responsible horseperson, so problematic myths are worth ferreting out to keep them from compromising our work.

So until next time...may the force be with you!

"Energy is an eternal delight."
~ William Blake

Related Posts with Thumbnails