PATH TRACING IN VOLUMETRIC SPACE USING STORED IRRADIANCE(International Workshop on Advanced Image Technology 2006)

概要

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3-dimentional raster ray tracing (RRT), one of the ray tracing acceleration techniques, renders voxelized polygon-based geometry by 3D scan conversion in a volume space with their attributes using 3-dimentional digital differrence analyzer (3DDDA). In this research, we adapt this technique to path tracing acceleration. First, we prepare a Euclidean unit space which is rough-divided into unit spaces. Each unit space is subdivided into the finer volume space called voxel space, which is consisted by (1pixel)^3 sized voxels when a bounding volume surrounding an object exists inside the unit space. Polygons in a scene are translated into these voxels with their attributes. Then this volume space is rendered with path tracing. For the acceleration of path tracing, we use irradiance cache technique. The calculated irradiance value by a primary ray at each voxel is stored in the voxel. The stored values are used instead of the calculation for secondary rays if it is possible. We also propagate calculated irradiance to the adjacent voxels which is expected to reduce the calculation number for secondary rays. In our technique, rendering speed is not much depends on the polygon number that is one of the features of RRT. In our experiment, an advantage against conventional path tracing is shown for rendering speed.
社団法人電子情報通信学会の論文
2006-01-02