Figure 1 : Common problems of ray tracing: On the left the problem of choosing a good epsilon environment in order to avoid self-intersections is shown. A too small epsilon results in self-intersections of secondary rays, while a too large epsilon results in overlaps from the extended geometry. On the right a light source close to a silhouette casts a long shadow. While the geometry approximation is not visible at the silhouette, the approximation becomes unavoidably obvious in the projection,

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... hich is difficult to predict in the tessellation process. ABSTRACT Instead of computing intersections along a ray, an algorithm is proposed that determines a point of intersection in object space. The method is based on the classical refinement of a hierarchy of axisaligned bounding boxes that is computed on the fly. Typical rendering artifacts are avoided by taking into consideration the precision of floating point arithmetic. In addition the method lends itself to a simple solution of the self-intersection problem. Considering the obtained precision the algorithm is efficient, simple to use, and to implement.