Anatomy Primer (Sculpting a Figure) (Digital Sculpting with Mudbox)

The tutorial in this topic has two purposes: to improve digital sculpting proficiency through practice and to introduce human anatomy as applied to art. Although this tutorial is self-contained, in that you could probably work through it without reading any other part of this topic.

The great masters of past ages knew the importance of anatomical knowledge, and their grasp of human anatomy is reflected in the quality of their masterpieces. So it is with modern artists; every successful figurative sculptor, creature designer, and character designer should understand the fundamentals of human anatomy. Unfortunately, learning anatomy alone can seem dull, so in this tutorial, you will sculpt a humanoid creature and at the same time, learn the basics of surface human anatomy.

Human anatomy as applied to art is critical to sculpting believable human figures and humanoid creatures. Even if your subject is a creature that bears little resemblance to normal humans, people viewing your work will intuitively notice incorrect proportions or faulty anatomy. Although the viewer may not, specifically, know what is wrong, the creature will seem abnormal or unbelievable. In the spirit of traditional life drawing and figurative sculpture, the appropriate names and proper relationships, locations, and correct shapes of superficial muscle groups and other anatomical landmarks will be emphasized in this tutorial.

Navigating Anatomical Space

To navigate or locate positions in three-dimensional (3D) space, coordinates along the x, y, and z axes are used. In the same fashion, to navigate anatomical space, directional terms are used to describe the location, orientation, and relationships among anatomical structures. For instance, to describe the location of the triceps, you could say that the triceps are inferior to the deltoids and posterior to the biceps. Using standard directional terms avoids lengthy complicated descriptions (Figure 4.1). Although there are many directional terms, Table 4.1 defines the common terms used in this tutorial.

FIG 4.1 Anatomical Directional Terms Describe the Locations and Relationships between Anatomical Structures.

TABLE 4.1 Anatomical Directional Terms

Quick Overview of Muscle Anatomy

Surface anatomy is governed by how skin and fat drape over bone and muscles and how muscles work with the underlying skeleton. Thus, it is important to understand the anatomical relationship between the muscles and the bones they move. Skeletal muscles always span a joint and attach by means of tendons to two or more bones to produce movement. This tutorial often refers to the origin and insertion points of muscles to describe their relationships with the surrounding structures. The origin of a muscle is attached to a fixed bone (relative to the joint), and the insertion of a muscle is attached to the freely moving bone. In the first panel of Figure 4.2, you can see that the deltoid spans the shoulder joint and has an anterior origin at the clavicle and a lateral insertion at the humerus. When the deltoid contracts, it helps to abduct, flex, and extend the arm. As a matter of interest, skeletal muscles always work in groups to coordinate movement.

Skeletal muscles are classified according to their shape and fiber arrangements, such as fusiform, covergent, multipennate, parallel, and bipennate, among other types.

FIG 4.2 Understanding How Skeletal Muscles Work, the Different Types of Muscles, and Their Three-Dimensional Relationships Will Help You to Sculpt More Natural and Organic Figures.

Although it is not critical to memorize the names of the different muscle classifications, it is very important to become familiar with the orientation of the fibers in the major muscle groups. This will help you to easily sculpt more organic and natural figures. In the first panel of Figure 4.2, the Pectoralis major is an example of a covergent muscle because its fibers converge at the insertion on the humerus. In the second panel, the biceps brachii is classified as fusiform because it has two proximal heads that fuse together to form a central belly. In contrast, the coracobrachialis is an example of a parallel muscle because its fibers run parallel to the length of the muscle.

Because the skeletal muscles are arranged in 3D space, it is critical to understand their anatomical positions and relationships with one another. For example, in the third panel of Figure 4.2, you can see that the biceps brachii emerges from underneath the deltoid and the pectoralis major. As it emerges, it is not on the same plane as the surrounding structures. It is difficult to grasp 3D anatomical relationships by viewing drawings or photographs, so it is important to study the figure in life.

Superhero Proportions

The subject of this tutorial is a humanoid creature of superhero proportions (Figure 4.3). This means that the subject has exaggerated human proportions, is more muscular, has longer limbs, larger hands and feet, and is taller than the average human. Although the subject has exaggerated proportions, much of normal human anatomy still applies in terms of the location and relationship of its anatomical framework.

FIG 4.3 Heroic or Superheroic Proportions Are Different Than Average Human Proportions; However, Normal Human Anatomy Still Applies.