NeGAS: Authoring System for 3DCG using extended turtle metaphor

A new type of Authoring System NeGAS for 3DCG animation is developed in which a user can easily manipulate three dimensional objects in 3DCG space on the computer. This system is described using an object oriented three dimensional Logo language called o3logo developed by us. The user can manipulate objects comfortably with the help of the turtle metaphor by using o3logo programming, programming palette and hardware interface called "Kame (Turtle Controller)" developed by us. Objects, cameras, lights and turtle in 3DCG space can be manipulated by using turtle commands in our system, so DMI (Direct Manipulation Interface) for 3DCG animation is realized in our NeGAS (Fig. 1). We have developed a visual action palette on o3logo, in which an user can manipulate them by cricking buttons on the palette instead of programming, to manipulate objects, cameras, lights and turtle in 3DCG space. We extend this visual palette to "o3Art" system by the adding several functions to form three dimensional body in 3DCG space to generate and form artful three dimensional object (Fig.3). About 600 users are using o3logo, o3Art and Negas in several Japanese universities, so we can refine the usability of our system. This research has been supported by the Japanese national research project called Intelligent Cluster Creation Project. Figrue 1. The Turtle Metaphor Figure 3. The whole aspect of o3Art system