My mentor kindly bought me a book called ‘ How your Horse Moves’, which is a visual guide to improving horse performance. It has become my bible whilst animating my film. It has been such a useful guide for understanding the skeletal, muscular and ligament systems work together. The book contains artwork that provides a living equine canvas that shows how bones and muscles work together to produce movement.
I found the chapter about body structure particularly useful. There is a section based on each part of the body, giving you an overview of how the body part moves. It was very helpful to understand why each muscled moved, as when animating I could consider how this would affect the movement. For example, the head and neck together account for 10 per cent of the horses body weight. The vertebra in the spine is flexible, to that there is considerable scope for movement when the head is raised or lowered. When animating, I was able to consider my findings and use them to help me animate a believable movement.
The main driving force of the horse is provided by the muscles of the hindquarters and upper hind limb. With this in mind, I knew that the gluteals in the backlegs would provide the forward propulsion and strength in the animation.
Whereas the hind limbs are the powerhouse of the horse, the forelimbs provide support, bearing 60% of the horses weight. They also aid balance and steering. Learning this, helped me to understand the how the front legs should be angled under the horses body for support and also how they should be aiding the balance as it moves across the screen.
The book covers in great depth how muscles create movement and how the movement causes a chain reaction throughout the horses body. There are two mains types of contraction within the muscles, Concentric which is when the muscle shortens to create movement. Secondly, Eccentric contraction is when a muscle gradually lengthens to control movement and to absorb shock during abrupt movement.
There is also Isometric contraction when a muscle is working hard but there is no change in the length as it contracts to maintain a position. As the horse moves, it uses all types of muscular contraction. Learning the types of muscle movement was so helpful to understand what the horse should be doing with its body and why. For example having concentric contraction in the back leg creates pushing movement in the legs. Also, having Isometric contraction in the neck to support the weight of the head.
Although I don’t have to animate any muscle movement in my rig, it was important to understand how each muscle moved as that affected the overall movement of the limbs. I learnt that muscles work in chains, which helped me to logically understand which limb should move first and how that would create a reaction in different parts of the body. The dorsal muscles are the muscles above the spine and behind the hip, they create extension of the spine and hip, dip the back and raise the head and neck. The Ventral muscles are based below the spine and in front of the hip. They create the flexion to support the posture of the horse. Both muscle groups must work in balance with each other to achieve correct movement.
This knowledge was very helpful specifically when I was animating a scene where my horse transitioned from walk to stop. Whilst the horse was stood still at the end, I needed to create slight movement so that it would look alive. Aside of having reference, I needed to create believable subtle movement through the horses body. Whilst animating subtle movements, I considered the muscle groups and how there would be a chain reaction through the whole body.
Alongside the movement, the book also helped me to understand the terminology movement. Specifically it helped me to understand how the front legs should be angled. The forward swing of the stride is known as protraction and the backward push is known as retraction. As the leg swings forward, just before it hits the ground it goes into retraction, in order to reduce the speed at which the limb makes contact with the ground. This helped me to understand what angle the hoof should be when it is in contact with the ground, also known as the stance phase.
All of these minute details are what makes the animation believable. I have learnt the importance of strong posing when animating a quadruped. The small visual details such as the stride length and the angle of the hoof, make a huge difference to the overall movement.
At the same time as trying to accomplish believable movement, I had to also try and master the horse’s behaviour. I had to consider how a horse would react in situations with different emotions. Through studying real life horse reference and spending time with Alice, I was able to understand the subtle differences in the horse’s body language when it was acting a certain way. For example how the ears would move or how they would flare their nostrils. Mastering believable movement and behaviour both lay in the attention to detail.
Higgins, G. and Martin, S. (2012). How your horse moves. Newton Abbot: David & Charles.