Designing the illumination of a scene is a di cult task because one needs to render the whole scene in order to look at the result. Obtaining the correct lighting e ects may require a long sequence of modeling rendering steps. We propose to use directly the highlights and shadows in the modeling process. By creating and altering these lighting e ects, the lights themselves are indirectly modi ed. We believe this new technique to design lighting is more intuitive and can lead to a reduction of the number of modeling rendering steps required to obtain the desired image. CR Categories and Subject Descriptors: I.3.7 Computer Graphics : Three-Dimensional Graphics and Realism. Interaction techniques. General Terms: Algorithms. Additional Key Words and Phrases: extended light source, shadow volume, soft shadows, hard shadows, interactive light modeling.