Anatomy-Based Modeling of the Human Musculature

Ferdi Scheepers, Richard E. Parent, Wayne E. Carlson, and Stephen F. May. Anatomy-based modeling of the human musculature (1.5M PDF). In Turner Whitted, editor, SIGGRAPH 97 Conference Proceedings, Annual Conference Series. ACM SIGGRAPH, Addison Wesley, August 1997.

All images and animations are
Copyright (c) 1997
Ferdi Scheepers, Richard E. Parent, Wayne E. Carlson, Stephen F. May

from the Video Proceedings (6.6M Quicktime)

Application of Muscle Models (stills and animation)

The fusiform muscle model. In this example the fusiform muscle model is used to simulate muscles of the upper arm. The view is from 'inside' the body looking to the right; the inclusion of the white object representing the breastbone is unfortunate, but it gives some positional perspective. Notice the bulging of the biceps brachii (left) and the triceps (right).

The multi-belly muscle model. The animation (left) and animation stills (right) illustrate the operation of the multi-belly muscle model. Here, the deltoid (on the shoulder) and the pectoralis major (on the chest) have been added. This sequence shows isotonic and isometric contraction. The latter occurs when the hand clenches into a fist.
The general muscle model. In this animation the trapezius and latissimus dorsi have been added. Both are represented using multiple instances of the general muscle model. Because of the viewpoint the latissimus dorsi cannot be seen, but the top of the trapezius is visible above the clavicle. Additional muscles have been added to the figure (serratus anterior, external oblique, rectus abdominus), but they do not move in this animation.

Skeletal Support (section 3 in paper)

The sequences below show various movements of right upper limb skeleton. Low level motion control is provided by binding articulation variables to joint angles (first four sequences). High-level motion control is illustrated in the last sequence where a single articulation variable clench is used to close and open the hand skeleton.

Muscle Bellies and Muscle Models (section 4)

Muscle bellies. Front and side views of fusiform, parallel, tapering, and expanding muscle bellies are shown in this animation. The representation of muscle bellies using ellipsoids are discussed in the paper, but the concept can easily be extended to represent muscle bellies with different shapes.
Muscle bellies with tendons. Tendons are added to each muscle belly in this animation. Tendons are nonelastic connective tissue that connects the belly of a muscle to its attachment.
Fusiform muscle model. This animation illustrates the operation of the fusiform muscle model given two muscles of equal volume, one with tendons and the other without. In effect, the tendons shorten the muscle belly which exaggerates the bulging.
Fusiform muscle model with self-adjusting tendon. In the prevous example, the angle between the lower tendon and the 'arm' it attaches to does not change. In this animation, the angle is adjusted automatically to keep the muscle's axis in a straight line. To the left is a parallel muscle model (not discussed in the paper).
Isotonic and isometric muscle contraction. This animation shows both types of muscle contraction. Isotonic contraction produces movement, while isometric contraction occurs when a muscle is tensed. Although the effect is subtle, the muscle in this example tenses in the last few frames of the animation.
Multi-belly muscle model. Two examples of the multi-belly muscle model are shown here, one with fusiform muscle bellies, the other with tapering muscle bellies (not discussed in the paper). Notice the curvature of the origin curve.
General muscle model. This animation shows front and side views of a muscle with a more complex shape. The general muscle model allows for the creation and deformation of muscles that can bend.

Generating Skin (section 5)

We are investigating anatomy-based models for generating skin surfaces based on the influence of underlying deformable structures. Implicit primitives are used to adjust the control points of bicubic patch meshes representing the skin.