This is the tenth in a series of articles on drawing for animation. In these articles I will be presenting the theory and practice of drawing as a "how to" instructional series. The lessons are based upon the Vilppu Drawing Manual and will in general follow the basic plan outlined in the manual. This is the same material that I base my seminars and lectures on at the American Animation Institute, UCLA, and my lectures at Disney, Warner Bros. and other major studios in the animation industry, both in the U.S. and their affiliates overseas. If you have not seen the previous lessons starting in the June 1998 issue of Animation World Magazine, it is recommended that you do. The lessons are progressive and expand on basic ideas. It is suggested that you start from the beginning for a better understanding of my approach.

Illustrations A, B, C & D. All drawings in this article are by and © Glenn Vilppu.

Indirect Lighting and Modeling Tone
The first half of this manual has been primarily concerned with creating form using line, emphasizing the need to visualize the whole form and to draw across the surface of the form to show its volume. In learning to see spheres, boxes, and cylinders, we focused on seeing the corners of forms and used these basic visual tools to help us see the orientation of the forms in space and to draw them. In reality, we see things primarily in tone, not line. I have used tone in many of my examples to define the forms without explaining the usage. In this chapter, and the next two, we will discuss three distinct methods of using tone. The three approaches, which are indirect lighting, direct lighting, and atmospheric perspective, are distinct but generally used in varying degrees together. For the purpose of teaching, I am focusing on each one as a separate and distinct approach. As you will see, they can be used as separate methods though they are generally used together.

The clarity of an edge of a form is defined by what is behind it. The greater the contrast the clearer the contour. A solid black object against a white background can appear quite flat without a light source defining the interior corners and the parts that come forward (see Illustration A). To create a strong sense of volume it is necessary to emphasize these internal corners that come forward and subordinate those that recede back in space.

Illustrations B, C, and D demonstrate the fundamental elements of the indirect lighting approach. The part that is facing you is the lightest and the form becomes darker as it turns away from you. Notice that I said, "Turns away from you." The important point here is the angle of the form in relationship to you. In Illustration C, the outside contour has also been softened to make it recede even more.

"What faces you is in light; what turns away from you is in tone."

What faces you is in light; what turns away from you is in tone. Another way of thinking about this is to imagine yourself as the source of light.

Illustration E gives an example of this basic principle. Remember, it is the angle that a particular surface plane faces that determines its value (degree of light and dark), not how far away from you it is.

This use of tone, or value, is usually referred to as a "modeling tone." We model the form using the tone to define itself in space in the same way a sculptor does. Since our main concern is to describe form, you must look at the basic procedure as a tool rather than a rule. We use the tone to push the sides back on a form.

Let us modify the basic concept now to read: "What faces you, relatively, is in light; what turns away from you is in tone." The word "relatively" is very important. Study Illustration F. This is actually an optical illusion. The forms can be seen going in or coming out. The parts of the forms that are in light do not actually face you, but, relative to the forms that are turned more away, they do. Notice that there is no difference between those forms that are close to you and those farther away. Of course, in reality, there is, but for the moment concern yourself only with the angle that the plane of the form is facing.