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21
Hierarchical Zbuffer visibility
 In Computer Graphics (SIGGRAPH ’93 Proceedings
, 1993
"... An ideal visibility algorithm should a) quickly reject most of the hidden geometry in a model and b) exploit the spatial and perhaps temporal coherence of the images being generated. Ray casting with spatial subdivision does well on criterion (a), but poorly on criterion (b). Traditional Zbuffer sc ..."
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Cited by 233 (1 self)
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An ideal visibility algorithm should a) quickly reject most of the hidden geometry in a model and b) exploit the spatial and perhaps temporal coherence of the images being generated. Ray casting with spatial subdivision does well on criterion (a), but poorly on criterion (b). Traditional Zbuffer scan conversion does well on criterion (b), but poorly on criterion (a). Here we present a hierarchical Zbuffer scanconversion algorithm that does well on both criteria. The method uses two hierarchical data structures, an objectspace octree and an imagespace Z pyramid, to accelerate scan conversion. The two hierarchical data structures make it possible to reject hidden geometry very rapidly while rendering visible geometry with the speed of scan conversion. For animation, the algorithm is also able to exploit temporal coherence. The method is well suited to models with high depth complexity, achieving orders of magnitude acceleration in some cases compared to ordinary Zbuffer scan conversion.
Ray Tracing Deformable Scenes using Dynamic Bounding Volume Hierarchies
 ACM Transactions on Graphics
, 2006
"... The most significant deficiency of most of today’s interactive ray tracers is that they are restricted to static walkthroughs. This restriction is due to the static nature of the acceleration structures used. While the best reported frame rates for static geometric models have been achieved using ca ..."
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Cited by 84 (18 self)
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The most significant deficiency of most of today’s interactive ray tracers is that they are restricted to static walkthroughs. This restriction is due to the static nature of the acceleration structures used. While the best reported frame rates for static geometric models have been achieved using carefully constructed kdtrees, this article shows that bounding volume hierarchies (BVHs) can be used to efficiently ray trace large static models. More importantly, the BVH can be used to ray trace deformable models (sets of triangles whose positions change over time) with little loss of performance. A variety of efficiency techniques are used to achieve this performance, but three algorithmic changes to the typical BVH algorithm are mainly responsible. First, the BVH is built using a variant of the surface area heuristic conventionally used to build kdtrees. Second, the topology of the BVH is not changed over time so that only the bounding volumes need to be refit from frametoframe. Third, and most importantly, packets of rays are traced together through the BVH using a novel integrated packetfrustum traversal scheme. This traversal scheme elegantly combines the advantages of both packet traversal and frustum traversal and allows for rapid hierarchy descent for packets that hit bounding volumes as well as rapid exits for packets that miss. A BVHbased ray tracing system using these techniques is shown to achieve performance for deformable models comparable to that previously available only for static models.
Applying Space Subdivision Techniques to Volume Rendering
 IEEE Visualization
, 1990
"... We present a new raytracing algorithm for volume rendering which is designed to work efficiently when the data of interest is distributed sparsely through the volume. A simple preprocessing step identifies the voxels representing features of interest. Frequently this set of voxels, arbitrarily dist ..."
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Cited by 28 (2 self)
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We present a new raytracing algorithm for volume rendering which is designed to work efficiently when the data of interest is distributed sparsely through the volume. A simple preprocessing step identifies the voxels representing features of interest. Frequently this set of voxels, arbitrarily distributed in three dimensional space, is a small fraction of the original voxel grid. A mediancut space partitioning scheme, combined with bounding volumes to prune void spaces in the resulting search structure, is used to store the voxels of interest in a kd tree. The tree is then efficiently raytraced to render the voxel data. The kd tree is view independent and can be used for animation sequences involving changes in positions of the viewer or positions of lights. We have applied this search structure to render voxel data from MRI, CAT Scan and electron density distributions. 1 Introduction An increasingly important application of computer graphics technology is in providing visualiza...
Geometric and Arithmetic Culling Methods for Entire Ray Packets
, 2006
"... Recent interactive ray tracing performance has been mainly derived from the use of ray packets. Larger ray packets allow for significant amortization of both computations and memory accesses; however, the majority of primitives are still intersected by each ray in a packet. This paper discusses seve ..."
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Cited by 20 (9 self)
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Recent interactive ray tracing performance has been mainly derived from the use of ray packets. Larger ray packets allow for significant amortization of both computations and memory accesses; however, the majority of primitives are still intersected by each ray in a packet. This paper discusses several methods to cull entire ray packets against common primitives (box, triangle, and sphere) that allows an arbitrary number of rays to be tested by a single test. This provides cheap “all miss ” or “all hit ” tests and may substantially improve the performance of an interactive ray tracer. The paper surveys current methods, provides details on three particular approaches using interval arithmetic, bounding planes, and corner rays, describes how the respective bounding primitives can be easily and efficiently constructed, and points out the relation among the different fundamental concepts.
Implementing ray tracing with octrees and neighbor finding
 Computers And Graphics
, 1989
"... AbstractA ray tracing implementation is described that is based on an octree representation of a scene. Rays are traced through the scene by calculating the blocks through which they pass. This calculation is performed in a bottomup manner through the use of neighbor finding. The octrees are assu ..."
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Cited by 18 (4 self)
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AbstractA ray tracing implementation is described that is based on an octree representation of a scene. Rays are traced through the scene by calculating the blocks through which they pass. This calculation is performed in a bottomup manner through the use of neighbor finding. The octrees are assumed to be implemented by a pointer representation. The most basic operation in computer graphics is the conversion of an internal model of a threedimensional scene into a twodimensional scene that lies on the viewplane. The purpose is to generate an image of the
Fast Ray Tracing Using KD Trees
, 1988
"... A hierarchical search structure for ray tracing based on kd trees is introduced. This data ..."
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Cited by 12 (0 self)
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A hierarchical search structure for ray tracing based on kd trees is introduced. This data
Cost Prediction for Ray Shooting
 PROC. OF EIGHTEENTH ACM SYMP. ON GEOM. COMPUT., 2002
, 2002
"... The ray shooting problem arises in many different contexts. For example... ..."
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Cited by 11 (4 self)
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The ray shooting problem arises in many different contexts. For example...
A Search Structure based on Kd Trees for Efficient Ray Tracing
, 1992
"... We present an experimental study of some of the important properties of space subdivision structures used to accelerate ray tracing. Location and orientation of partitioning planes, use of bounding volumes, methods to isolate void spaces in hierarchies and choice of traversal methods are examined to ..."
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Cited by 11 (0 self)
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We present an experimental study of some of the important properties of space subdivision structures used to accelerate ray tracing. Location and orientation of partitioning planes, use of bounding volumes, methods to isolate void spaces in hierarchies and choice of traversal methods are examined to determine their effect on performance. This has resulted in the development of a new search structure based on kd trees, which outperform acceleration schemes that exploit only a subset of the above characteristics. In addition to superior performance and greater adaptivity to scene characteristics, the flexibility of this structure allows it to terminate itself at the correct point, unlike the ad hoc schemes used by existing methods. This structure has been applied successfully to volume visualization applications, resulting in significant performance advantages. 1 Introduction A great deal of research has focused on discovering efficient ways to perform ray tracing, a sophisticated rend...
Early split clipping for bounding volume hierarchies
 IN PROCEEDINGS OF THE 2007 IEEE/EG SYMPOSIUM ON INTERACTIVE RAY TRACING
, 2007
"... Despite their algorithmic elegance and robustness, bounding volume hierarchies (BVHs) have not reached the performance of kdtrees for ray tracing. BVHs do not adapt well to scenes containing large triangles with overlapping bounding boxes. A node cannot be smaller than the bounding box of the primit ..."
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Cited by 9 (0 self)
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Despite their algorithmic elegance and robustness, bounding volume hierarchies (BVHs) have not reached the performance of kdtrees for ray tracing. BVHs do not adapt well to scenes containing large triangles with overlapping bounding boxes. A node cannot be smaller than the bounding box of the primitives it contains. Consequently, the leafs and internal nodes will overlap substantially. This slows down ray tracing, because the number of traversal steps and rayprimitive intersections is increased. Unfortunately, this kind of geometry is common in architectural scenes and lowpoly CAD models. In this paper, we present a building algorithm for BVHs that handles such scenes more efficiently. The restriction that each primitive must be contained in exactly one leaf node is relaxed. Bounding boxes of large primitives are refined with recursive split clipping before constructing the hierarchy. The resulting volumes are used as input for a regular BVH building algorithm. Neither scene geometry nor traversal or building algorithms must be modified in any way. The resulting hierarchies are superior for a wide range of data sets, leading to speedups of more than a factor of three.
Ray Tracing: A Quantitative Analysis and a New Practical Algorithm
 The Visual Computer
, 1995
"... We present a new method to accelerate the process of finding nearest rayobject intersections in ray tracing. The algorithm consumes an amount of memory more or less linear in the number of objects. The basic ideas can be characterized with a modified BSPtree and plane traversal. Plane traversal ..."
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Cited by 7 (6 self)
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We present a new method to accelerate the process of finding nearest rayobject intersections in ray tracing. The algorithm consumes an amount of memory more or less linear in the number of objects. The basic ideas can be characterized with a modified BSPtree and plane traversal. Plane traversal is a fast linear time algorithm to find the closest intersection point in a list of bounding volumes hit by a ray. We use plane traversal at every node of the high outdegree BSPtree. Our implementation is competitive to fast ray tracing programs. We present a benchmark suite which allows for an extensive comparison of ray tracing algorithms. Keywords: ray tracing, space subdivision, plane traversal, octree, clustering, benchmark scenes 1 Introduction Ray tracing, the well known rendering technique which produces high quality images, simulates geometric optics by tracing rays of light from a virtual viewpoint into an object space. Realistic images are the result of applying illumination m...