Torso dynamics (directions of torso and pelvis; rib cage–pelvis relationship)
Show how the rib cage and pelvis tilt, twist, and relate to each other in a moving figure.
What it is
Torso dynamics means reading and inventing the directions of the rib cage and pelvis. You show whether the chest leans, tilts, or twists against the hips through gesture and construction lines.
Treat the rib cage and pelvis as solid units connected by a flexible spine. Their angles can oppose each other in standing poses, or show folding, extension, and rotation in crouching and reaching poses.
Use opposing angles and twists, including the front planes of the rib cage and pelvis and the top planes of the shoulders and hips. In thumbnails or quick sketches, these two forms should still show the figure's action and attitude.
Why it matters
Torso dynamics helps show weight shift, gesture, and emotion with few lines. Weak control can make poses look stiff and weightless, with limited twist, bend, or compression at the waist.
You can check it when
- ✓Draw simple box or egg forms over your gestures for the rib cage and pelvis. Their tilts and directions differ when the pose calls for it.
- ✓Mark the chest-facing and pelvis-facing directions in reference with simple axis lines.
- ✓Check standing and walking figures for opposing shoulder and hip angles.
- ✓Mark the rib cage and pelvis orientation before adding details such as muscles, breasts, or clothing folds in an invented pose.