This paper proposes a three-dimensional computer animation method for behavioral description of crowd, a throng of people, in a virtual city. In the method, each human character in the computer generated city is assigned his/her own personal space, which prescribes the regions around the character where another character may stay or cannot. As for any other environmental object in the city, such as roads, trees, and cars, a similar “personal” space is also specified. Associated with these personal spaces, the vector field, called attractiveness, is generated and enables to describe various behavioral animations of crowd.The uniqueness and efficiency of the proposed method is well illustrated by the animations obtained, which include the description of psychologically based personal space, walking on a pavement, and behaviors of avoiding collision with cars.