Having a good understanding of geometric-shapes and forms and observing them in what you are trying to draw, helps your understanding of the structure of what you are observing. You can find these basic shapes in most everything you will be draw from observation, whether a mechanical object or organic object in nature. Simple examples of this are trees. We can easily see the relationship of these basic geometric forms in the mass of the leaves on trees, shaped like spheres, cones or cubes.
This exercise is to help you understand these shapes and forms. It will also have you begin to imagine how light affects three-dimensional objects and how cast shadows form from these objects.
Materials: HB pencil and Sketchbook.
Start by drawing the three basic shapes, circle, triangle, and square all the same size, freehand, don't be afraid to constantly correct the drawing as needed to perfect the shapes (no rulers). Along side of the basic shapes, draw the 3D equivalents, a sphere, cone, and cube. Pretend there is a single light source in the 10:00 o'clock position above them. Imagine how the objects would be lit and where the shadow on the forms would be and how the cast shadow would fall and what the cast shadows shape would look like. Next to the three-dimensional forms draw a variation of the cone, which would be a cylinder, and a variation next to the cube, a pyramid. Now draw in the light and shadow sides of the forms, and the shadow that is casts form the form (Cast Shadow) from these objects. See sample drawing exercise below.
This exercise is designed to make you use only your minds-eye to create these objects and the lighting affect.