Abstract: In this paper, an algorithm for speeding up ray tracing solid models is introduced. The object space is. organized as an array of cubes. Different kinds of objects are represented by different models for efficient ray tracing. The cells and the objects in the object space are linked by intersection relationship.To test wheth er a ray intersects any object, objects are tested in the order as they occur on the path of the ray. Details of the implementation are given.The structure of object space is not only useful for image generating,but also helpful in solving other probl ems, such as spatia search, visibility prediction, interference test, path planning, and the boolean combination of solid objects. The structure of object space can also. be mapped onto parallel computer architecture for parallel processing.