Ray Bilinear Patch Intersections
TL;DR: This work considers intersections between rays and the simplest parametric surface, the bilinear patch, and presents a complete, efficient, robust, and graceful formulation to solve ray-bilinearpatch intersections quickly.
Abstract: Ray tracing and other techniques employ algorithms which require the intersection between a three-dimensional parametric ray and an object to be computed. The object to intersect is typically a sphere, triangle, or polygon but many surface types are possible. In this work we consider intersections between rays and the simplest parametric surface, the bilinear patch. Unlike other surfaces, solving the ray-bilinear patch intersection with simple algebraic manipulations fails. We present a complete, efficient, robust, and graceful formulation to solve ray-bilinear patch intersections quickly. Source code is available online.
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01 Jul 2012
TL;DR: The roots of the nonlinear system of equations defining CCD through careful consideration of the boundary of the parameter domain are analyzed, and only the parity of the number of collisions is needed for robust simulation, and this parity can be calculated with simpler non-constructive predicates.
Abstract: Continuous collision detection (CCD) between deforming triangle mesh elements in 3D is a critical tool for many applications. The standard method involving a cubic polynomial solver is vulnerable to rounding error, requiring the use of ad hoc tolerances, and nevertheless is particularly fragile in (near-)planar cases. Even with per-simulation tuning, it may still cause problems by missing collisions or erroneously flagging non-collisions. We present a geometrically exact alternative guaranteed to produce the correct Boolean result (significant collision or not) as if calculated with exact arithmetic, even in degenerate scenarios. Our critical insight is that only the parity of the number of collisions is needed for robust simulation, and this parity can be calculated with simpler non-constructive predicates. In essence we analyze the roots of the nonlinear system of equations defining CCD through careful consideration of the boundary of the parameter domain. The use of new conservative culling and interval filters allows typical simulations to run as fast as with the non-robust version, but without need for tuning or worries about failure cases even in geometrically degenerate scenarios. We demonstrate the effectiveness of geometrically exact detection with a novel adaptive cloth simulation, the first to guarantee to remain intersection-free despite frequent curvature-driven remeshing.
109 citations
01 Jan 2006
TL;DR: A global illumination algorithm is proposed that efficiently combines optimized ray tracing and the parallelization framework that makes it possible to compute complete global illumination at interactive frame rates.
Abstract: In computer graphics, ray tracing has become a powerful tool for generating realistically looking images. Even though ray tracing offers high flexibility, a logarithmic scalability in scene complexity, and is known to be efficiently parallelizable, its demand for compute power has in the past lead to its limitation to high-quality off-line rendering. This thesis focuses on the question of how realtime ray tracing can be realized on current processor architectures. To this end, it provides a detailed analysis of the weaknesses and strengths of current processor architectures, for the purpose of allowing for highly optimized implementation. The combination of processor-specific optimizations with algorithms that exploit the coherence of ray tracing, makes it possible to achieve realtime performance on a single CPU. Besides the optimization of the ray tracing algorithm itself, this thesis focuses on the efficient building of spatial index structures. By building these structures from scratch for every frame, interactive ray tracing of fully dynamic scenes becomes possible. Moreover, a parallelization framework for ray tracing is discussed that efficiently exploits the compute power of a cluster of commodity PCs. Finally, a global illumination algorithm is proposed that efficiently combines optimized ray tracing and the parallelization framework. The combination makes it possible to compute complete global illumination at interactive frame rates.
101 citations
TL;DR: An efficient and robust particle-localization algorithm for unstructured grids which can detect inconsistencies without resorting to fall-back algorithms such as exhaustive or Octree search is presented.
71 citations
15 Feb 2008
TL;DR: This paper presents a GPU-based, fast, and accurate dynamic height field rendering technique that scales well to large scale height fields using maximum mipmaps, a hierarchical data structure supporting accurate and efficient rendering while simultaneously lowering the pre-computation costs to negligible levels.
Abstract: This paper presents a GPU-based, fast, and accurate dynamic height field rendering technique that scales well to large scale height fields. Current real-time rendering algorithms for dynamic height fields employ approximate ray-height field intersection methods, whereas accurate algorithms require pre-computation in the order of seconds to minutes and are thus not suitable for dynamic height field rendering. We alleviate this problem by using maximum mipmaps, a hierarchical data structure supporting accurate and efficient rendering while simultaneously lowering the pre-computation costs to negligible levels. Furthermore, maximum mipmaps allow for view-dependent level-of-detail rendering. In combination with hierarchical ray-stepping this results in an efficient intersection algorithm for large scale height fields.
71 citations
TL;DR: A full architecture built around spectral light transport and a flexible implementation of multiple importance sampling is described, resulting in a system able to support a comparable amount of extensibility to what made the reyes rendering architecture successful over many decades.
Abstract: The Manuka rendering architecture has been designed in the spirit of the classic reyes rendering architecture: to enable the creation of visually rich computer generated imagery for visual effects in movie production. Following in the footsteps of reyes over the past 30 years, this means supporting extremely complex geometry, texturing, and shading. In the current generation of renderers, it is essential to support very accurate global illumination as a means to naturally tie together different assets in a picture. This is commonly achieved with Monte Carlo path tracing, using a paradigm often called shade on hit, in which the renderer alternates tracing rays with running shaders on the various ray hits. The shaders take the role of generating the inputs of the local material structure, which is then used by path-sampling logic to evaluate contributions and to inform what further rays to cast through the scene. We propose a shade before hit paradigm instead and minimise I/O strain on the system, leveraging locality of reference by running pattern generation shaders before we execute light transport simulation by path sampling. We describe a full architecture built around this approach, featuring spectral light transport and a flexible implementation of multiple importance sampling (mis), resulting in a system able to support a comparable amount of extensibility to what made the reyes rendering architecture successful over many decades.
41 citations
Cites background from "Ray Bilinear Patch Intersections"
...This approach can be usefully paired with our intersection test for bilinear patch micropolygons, which is a similarly adjusted version of the test described by Ramsey et al. (2004)....
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References
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01 Jan 1994
TL;DR: The Diskette v 2.06, 3.5''[1.44M] for IBM PC, PS/2 and compatibles [DOS] Reference Record created on 2004-09-07, modified on 2016-08-08.
Abstract: Note: Includes bibliographical references, 3 appendixes and 2 indexes.- Diskette v 2.06, 3.5''[1.44M] for IBM PC, PS/2 and compatibles [DOS] Reference Record created on 2004-09-07, modified on 2016-08-08
19,881 citations
Book•
11 Feb 1989
1,178 citations
"Ray Bilinear Patch Intersections" refers background or result in this paper
...Another common formulation of ray bilinear patch intersections represents the ray as the intersection of two planes (see [ 3 ])....
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...We show a more complete and graceful formulation than previously presented ([ 3 ])....
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Book•
01 Jan 2000
TL;DR: This book will guide you through the steps of creating your own powerful ray tracer program, proceeding from simple images through advanced special effects such as soft shadows, glass and metal textures, and motion blur.
Abstract: From the Publisher:
Realistic Ray Tracing is an innovative, in-depth look at the theory and techniques of ray tracing, a method of producing photorealistic computer graphics images by applying simple algorithms. This book will guide you through the steps of creating your own powerful ray tracer program, proceeding from simple images through advanced special effects such as soft shadows, glass and metal textures, and motion blur. It concentrates on the nuts and bolts of writing ray tracing programs, with plenty of practical, detail-oriented how-to advice and careful attention to the underlying theory.
247 citations
26 Jun 2000
TL;DR: An algorithm for ray tracing displacement maps that requires no additional storage over the base model and a special purpose displacement that creates a smooth surface that interpolates the triangle vertices and normals of a mesh is discussed.
Abstract: We present an algorithm for ray tracing displacement maps that requires no additional storage over the base model. Displacement maps are rarely used in ray tracing due to the cost associated with storing and intersecting the displaced geometry. This is unfortunate because displacement maps allow the addition of large amounts of geometric complexity into models. Our method works for models composed of triangles with normals at the vertices. In addition, we discuss a special purpose displacement that creates a smooth surface that interpolates the triangle vertices and normals of a mesh. The combination allows relatively coarse models to be displacement mapped and ray traced effectively.
43 citations