Current rendering algorithms of global illumination models can generate photo-realistic images

but the high computing cost may discourage their applications in walk-through and virtual reality etc. Especially

rendering specular reflections and refractions is always a problem in computer graphics community. In this paper

virtual optical-mapping objects are introduced

and a unified method for generating virtual objects of reflections and refractions is proposed. The virtual objects are treated in the same way as real objects in the scene

so the reflection and refraction images can be rendered by the graphical hardware. Cluster based connected PCs is utilizes as parallel platform

and task scheme and load balance are discussed. Virtual objects are generated by CPU and rendered by graphical hardware. So

this method utilizes simultaneously both CPUs and graphical hardware on nodes of clusters to achieve high performance rendering. In the last

examples demonstrate this method is powerful for interactive applications such as real-time walk-throughs in buildings

animation and virtual reality.