Cast Shadows and Three-Dimensional Form
In your efforts to convey three-dimensions in your drawings, it is helpful to remember the following points:
- Shadows serve to define the internal contours of an object.
- Cast shadows serve to orient an object in its environment; they also help to describe that environment.
For example, a cast shadow that is not connected to the object that casts it indicates that the object is floating in the air. A cast shadow that duplicates the silhouette of the object indicates that the surface receiving the cast shadow is parallel to the picture plane and the light source is near the observer. The curves in the cast shadow of a straight object help describe the curved surface receiving the shadow.
The characteristics that distinguish cast shadows from stains, wet spots, and other variations in value are these:
- A cast shadow is darkest near the object that casts it and lightest at the point farthest from that object.
- A cast shadow's edge is in sharpest focus near the object casting the shadow and becomes softer farther away from that object.
The cast shadow of the pencil helps define the contours of the fingers.
The cast shadow of the cylinder defines the ground plane and helps to define the steps .
In the drawing at near right the separation between the bird and its cast shadow shows that the bird is off the ground. In the drawing at far right the bird's cast shadow tells us that there is a wall close to the bird and that the light source is frontal.
The edge of the seal's cast shadow describes the gravel shore.
The cast shadow of the beehive implies the texture of the grass, even where grass has not been drawn.