The generation of characters within computer animations is a labor intensive and expensive activity. Whereas prior art approaches have sought to reduce this loading by providing reference avatars, these do not fundamentally overcome the intensive steps in generating these reference avatars, and they provide limited variations to the businesses employing them. Accordingly the invention provides the user with a simple and intuitive mechanism to affect the weightings applied in establishing the physical characteristics of an avatar generated using an inheritance based avatar generator. The inheritance based generator allowing, for example, the user to select a first generation of four grandparents, affect the weightings in generating the second generation parents, and subsequently affect the weightings in generating the third generation off-spring avatar from these parents, therein providing a wide range of avatars from an initially limited set of avatars. Accordingly the invention provides animators with a means of rapidly generating and refining the off-spring avatar to provide the character for their animated audio-visual content.