Description This lesson explains follow-through motion as it is applied to secondary actions as well as character animation.

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Hannah Sara Byrd
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1 1 Fundamentals of follow-through Objectives After completing this lesson, you will be able to: Explain how movement flows from one part to the next. Describe the fundamentals of follow-through motion as it applies to animation. Description This lesson explains follow-through motion as it is applied to secondary actions as well as character animation. Learning Outcomes Students will understand the fundamentals of follow-through motion, and how it is applied to character animation. Introduction Follow-through motion is fundamental to human figure movement. Movement is always initiated in one part of the body and travels along the body s kinetic chains. Follow through is about the details of body part articulation: where movement initiates in the body, and how it sequences from one part to the next. The initiation and sequencing serve to visually locate the center of mass and indicate the transfer of weight through the joints. Combined with elasticity, follow through supports the physical materiality of forms in motion. Definition of Follow Through Follow-through motion occurs when one part leads an action and other parts follow. For example, in a side-toside waving action, the elbow leads, with the hand and fingers following afterwards. The motion has a characteristic S-shape that undulates. Figure 1: Follow through in a waving gesture

2 Follow through is about initiation and sequencing: where does the movement start? How does movement travel along the connected parts? How stiff or loose are the connected parts?

2 2 Follow through is about initiation and sequencing: where does the movement start? How does movement travel along the connected parts? How stiff or loose are the connected parts? The sequencing of follow-through motion is distinctively successive, where parts move one after the other. The shape of the connected parts has a characteristic S-shape. The part that initiates the movement can change its direction while the trailing parts are still catching up to it. Simultaneous sequencing is when all the parts move at once, and is not considered as follow-through motion. Figure 2: Incorrect follow through Note that in this illustration, the wave gesture looks more like bamboo blowing in the wind! The shape of the arm is an arc, as opposed to an S. In addition to follow-through motion in the body, you tend to see follow-through motion as secondary action, which refers to parts that move as the result of the main action, but are not key components of it. Hair, clothing, and props fall into this category. Follow-through motion is often paired with overlapping action. Overlapping action occurs when a new movement begins before the previous one has ended. Typically, an action has completed but parts are still following through. In the next lesson on jumping, you will read more discussion of follow through and overlapping in the context of movement phrasing. Follow Through and Human Figure Motion The human body is a series of kinetic chains that are interconnected through complex systems. 3D computer animation character rigs can only approximate the complexity of movement possible. Character rigs typically define the kinetic chains through bone object hierarchies as follows: Pelvis > lumbar spine > thoracic spine > neck (cervical spine) > head Shoulder > upper arm > forearm > hand > fingers Pelvis > thigh > calf > foot > toes

Some software programs have full body inverse kinematics, which enables you to move all parts into position intuitively. Character rigs are scene objects that help you pose and animate the character.

3 3 Character rigs offer a combination of forward and inverse kinematic controls for various parts of the body. Typically, you have the ability to switch between forward and inverse kinematics for the arms and legs, and you will be working with forward kinematics for the spine. Some software programs have full body inverse kinematics, which enables you to move all parts into position intuitively. Character rigs are scene objects that help you pose and animate the character. A character rig is analogous to a marionette puppet its movement is controlled by a frame and strings. Rigs are constructed from interior bone objects that provide the character s anatomical structure. The movement of the bones is controlled by additional control objects that are located outside the character mesh and are easy to select and manipulate. Follow-through motion goes hand in hand with forward kinematics because it is essentially a forward kinematic motion. However, you can pose a character using inverse kinematics so that the results have follow-through motion. Animating with forward kinematics generally offers you a more intuitive way to create follow through.

4 4 Note: An object hierarchy is made up of parent-child relationships. For example, the upper arm bone is the parent of the lower arm bone. When the upper arm rotates, the lower arm stays connected to it and inherits its motion. The lower arm can rotate on its own while it inherits the upper arm s motion. This method for manipulating a hierarchy of objects is called forward kinematics. When posing a character using forward kinematics, you generally rotate the parent bone first, and then move forwards down the hierarchy to the child objects. Inverse kinematics is a method that enables you to pose the character by moving the end of a limb. For example, if you move the hand to a table top, the elbow and shoulder joints will bend. Many people prefer to animate with inverse kinematics because it is conceptually similar to the way our brains plan and execute movement. Follow-through motion occurs along the spine and in the limbs. Made of twenty-four vertebrae, the spine is incredibly mobile and capable of waving, snake-like action. Generally, follow-through motion in the spine is initiated in the pelvis and travels up through the lumbar, thoracic, and cervical sections, ending with the head. We are also capable of initiating follow-through motion from the head, sending a wave down to the pelvis. You may be able to observe this motion in hip-hop or break dancing. Some 3D character rigs may offer limited ability for this type of motion. The arms also are capable of follow-through motion that is initiated either at the shoulder or the fingertips. While the axes of rotation are limited in the elbow and finger joints, the incredible three-dimensionality of the shoulder and wrist joints enable smooth, flowing follow-through motion. In the ballet Swan Lake, the lead swan dancer continuously waves her arms like bird wings, initiated at the shoulder and flowing along the arm to the fingertips. Again, in hip-hop you can observe an arm wave that starts with the fingertips and moves up the arms to the shoulder. Follow-through motion in the legs is more limited because the knee joint is a hinge that rotates on one axis only. Additionally, the leg is a limb that has both ends of its kinetic chain involved in weight support most of the time. When the foot is free, the leg can achieve follow-through motion in actions such as kicking, where the leg moves from flexion into extension going forwards. More limited follow through is achieved when extending the leg backwards, through the action of the foot only, as in moon-walking. You can also observe follow through as full-bodied motion that moves through the spine and the limbs. This type of full-body connectivity is beautiful to observe, and can be seen in all forms of sports, martial arts, dance, and so on. Full-body connectivity is one of the challenges of animating 3D characters due to its complexity and the limited ability of character rigs to approximate the capabilities of the human body. While character rigs can be very sophisticated, on a certain level, the body is still posed in a very puppet-like fashion. This is where developing your movement observation skills becomes critical to the success of your animation.

5 5 Weight, Effort, and Materiality Each body part has its own mass and requires energy and effort to move it. Follow-through motion involves the transfer of weight from one part to the next. You can observe this through varying qualities of weight combined with follow-through motion. Imagine you are ill and very weak try lifting your arm and let your whole arm, hand, and fingers feel heavy. Let the joints of your arm feel loose and flexible as you wave your arm up and down, and let your hand flop. Now try stiffening your arm muscles and do the same waving motion with a strong, controlled arm. Next, let the muscles soften but keep the motion the same, achieving a graceful delicacy. Each variation requires you to handle your energy in a different way. Notice how your intent changes as well as if you are a different person each time you vary your energy. Walking involves the exertion of weight and includes follow-through motion. Because walking is a whole-body action in contact with the ground, where you continuously give in to gravity and then push upwards against it, the energy required to move the body is visible through follow-through motion. The continuous flexion and extension of limbs in walking is analogous to squash and stretch, and can have an elastic quality that also characterizes the energy of a walk cycle. Variables such as body type (the materiality of the body) and character personality impact how a character handles their weight, and how the follow-through motion is stylized. Summary Follow-through motion is a fundamental animation concept that plays a sophisticated role in all character animation. It is about the relationship of body parts to each other; the connectivity of the parts to each other and to the whole. This relationship is described through the timing and direction of body part rotations, indicating where movement is initiated and how it flows along the body s kinetic chains. Note: Review your walk cycle animation and observe which parts of the movement have follow through. Try refining your walk cycle by exaggerating the follow through and see how it affects your animation.

Daily. Workout MOBILITY WARM UP Exercise Descriptions. (See Below)

Daily. Workout MOBILITY WARM UP Exercise Descriptions. (See Below) MOBILITY WARM UP Pelvic Tilt Lateral Pelvic Tilt Hip Circles Lateral Spine Glide Spinal Flexion and Extension Lateral Spinal Flexion Neck Juts and Tucks Neck Glides Arm Screws Arm Circles Elbow Circles