自底向上构建高效BVH的研究

光线追踪中,加速结构对于减少光线与几何体求交的计算量起到了不可或缺的作用,找到一种高效的加速结构仍然是本领域的研究热点之一.传统的加速结构如BVH,都是自顶向下的构建方式,由于其本身的限制,构造出的加速结构往往不是最优的.为了改进自顶向下的缺陷,提出了一种自底向上BVH的构建方式,它使用了BVH和空间划分的混合结构,并引入了一种改进的表面积启发代价函数和多个构建参数来优化最后的构建结果.最后实验表明,此文中提出的方式比传统的BVH与KD-Trees有更好的加速效果,可以实现对前两者5%-10%的提速.最后,文中还给出了一些加速方案来减少构建时间.

Research on Bottom-Up Approach to Build an Effective BVH

In ray tracking, acceleration structure is indispensable for reducing computation time of ray-geometry intersection. Finding an efficient and high quality acceleration structure is still an active area of research. The top-down approach is widely used in building acceleration structure, such as BVH. However, due to its limitation, the result tree is not always optimal. This paper presents a bottom-up approach to build an effective BVH which is a hybrid between BVH and Space Partitioning. An improved surface area heuristic cost function and multiple parameters have also been used to optimize this model. Experiments show that the approach mentioned above is more effective than the conventional BVH and KD-Trees. It can realize 5%-10% performance improvement. Furthermore, the way to reduce the building time has been investigated in this paper.