Ray tracing is a well-known technique for generating realistic images. One of the major drawbacks of this approach is the extensive computational requirement for imagé calculation. We suggest an algorithm to speed this calculation up. We first build tools to measure, between two instants, the influence of the 3D motion of objects on their 2D image. We then use this information to calculate a realistic animation whith a good speed-up. There isn't any limitation either on objects or on eye movements. The animation needs not being known at start, and this method may be used in real-time.
