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A Fast RayTracing Using Bounding Spheres and Frustum Rays for Dynamic Scene Rendering
Kenichi SUZUKI Yoshiyuki KAERIYAMA Kazuhiko KOMATSU Ryusuke EGAWA Nobuyuki OHBA Hiroaki KOBAYASHI
Publication
IEICE TRANSACTIONS on Information and Systems
Vol.E93D
No.4
pp.891902 Publication Date: 2010/04/01 Online ISSN: 17451361
DOI: 10.1587/transinf.E93.D.891 Print ISSN: 09168532 Type of Manuscript: PAPER Category: Computer Graphics Keyword: computer graphics, ray tracing, intersection test, bounding volume, bounding sphere,
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Summary:
Ray tracing is one of the most popular techniques for generating photorealistic images. Extensive research and development work has made interactive static scene rendering realistic. This paper deals with interactive dynamic scene rendering in which not only the eye point but also the objects in the scene change their 3D locations every frame. In order to realize interactive dynamic scene rendering, RTRPS (Ray Tracing based on Ray Plane and Bounding Sphere), which utilizes the coherency in rays, objects, and groupedrays, is introduced. RTRPS uses bounding spheres as the spatial data structure which utilizes the coherency in objects. By using bounding spheres, RTRPS can ignore the rotation of moving objects within a sphere, and shorten the update time between frames. RTRPS utilizes the coherency in rays by merging rays into a rayplane, assuming that the secondary rays and shadow rays are shot through an aligned grid. Since a pair of rayplanes shares an original ray, the intersection for the ray can be completed using the coherency in the rayplanes. Because of the three kinds of coherency, RTRPS can significantly reduce the number of intersection tests for ray tracing. Further acceleration techniques for rayplanesphere and raytriangle intersection are also presented. A parallel projection technique converts a 3D vector inner product operation into a 2D operation and reduces the number of floating point operations. Techniques based on frustum culling and binarytree structured rayplanes optimize the order of intersection tests between rayplanes and a sphere, resulting in 50% to 90% reduction of intersection tests. Two raytriangle intersection techniques are also introduced, which are effective when a large number of rays are packed into a rayplane. Our performance evaluations indicate that RTRPS gives 13 to 392 times speed up in comparison with a ray tracing algorithm without organized rays and spheres. We found out that RTRPS also provides competitive performance even if only primary rays are used.

