Where results make sense

About us   |   Why use us?   |   Reviews   |   PR   |   Contact us

Distributed ray tracing - Wikipedia, the free encyclopedia Distributed ray tracing, also called distribution ray tracing and stochastic ray tracing, is a refinement of ray tracing that allows for the rendering of "soft" phenomena. Distributing rays in the spectrum allows for the rendering of dispersion effects, such as rainbows and prisms. Conventional ray tracing estimates these integrals by sampling the value of the integrand at a single point in the domain, which is clearly a very bad approximation. en.wikipedia.org /wiki/Distributed_ray_tracing   (454 words)

Ray tracing - Wikipedia, the free encyclopedia Ray tracing is a general technique from geometrical optics of studying the path taken by light by following rays of light as they interact with optical surfaces. Ray tracing's popularity stems from its realism over other rendering methods (such as scanline algorithms); effects such as reflections and shadows, which are difficult to simulate in other algorithms, follow naturally from the ray tracing algorithm. Tracing rays in such a way on a computer to simulate this real-world process would be extremely wasteful, as only a minuscule fraction of the rays in a scene would reach the eye. en.wikipedia.org /wiki/Ray_tracing   (1570 words)

Distributed Ray Tracing Distributed ray tracing is a ray tracing method based on randomly distributed oversampling to reduce aliasing artifacts in rendered images. Distributed ray tracing achieves this type of translucent surface by casting randomly distributed rays in the general direction of the transmitted ray from traditional ray tracing. If N rays are cast initially and then those rays reflect off a glossy surface and each generate N more rays, and each of those hit an object that has to be checked for shadow by casting N more rays, etc. then the computation time of distributed ray tracing can quickly become unmanageable. www.cs.helsinki.fi /group/goa/render/rt/dist/dist.html   (1895 words)

Distributed Ray Tracing - Summary - 782 Lab3 - Distributed Raytracer - Vince Scheib & Ryan Geiss   (Site not responding. Last check: 2007-11-04) Ray tracing, the process of recursively intersecting a parameterized line equation with surfaces, is a simple and elegant rendering algorithm. In the distributed algorithm the reflected ray is perturbed slightly. Distributing the eye position over the area of a virtual lens, while maintaining the center of interest, causes defocusing of objects not on the focal plane. www.scheib.net /school/782/lab3/paper_sum1.html   (352 words)

Untitled Document   (Site not responding. Last check: 2007-11-04) By applying ray distribution, objects reflected in one another may appear blurred depending on the glossiness of the material and refracted light may be scattered as it passes from one medium to another. Using distributed ray tracing also allows the simulation of depth of field blur which is an artefact generated by a lens focusing on objects at varying distances. Any object that is intersected by the rays and that lies at a distance from the lens roughly equal to f will be in focus since the four rays that comprise that pixel will intersect at the same point on the object and will record more or less equal intensities. www.raytracing.co.uk /study/fx_drt.htm   (410 words)

Distributed Ray Tracer Distributed Ray Tracing (DTR) is one of most elegent techniques to create nice images with special effects such as motion blur, depth of field and translucency. Motion blur is achieved by sampling the distributed rays in temporal according to animating frames. Translucency is achieved by distributing the secondary rays along the main direction of the transmitted ray. www.cse.ohio-state.edu /~crawfis/cis782/Labs/FinalProjects/Distributed%20Ray%20Tracer.htm   (285 words)

[No title] By tracing bounds of rays in a pixel, along the direction of reflection, refraction or to light sources, it is possible to obtain an upper bound on the degree of aliasing in the pixel. The paraxial approximation theory for efficiently tracing a pencil of rays is described and analysis of its errors is conducted to insure the accuracy required for pencil tracing. The distribution of the objects among the regions is evaluated, and a method to compute the average number of regions crossed by a ray for a given method of subdivisions is proposed. www.cg.tuwien.ac.at /~wonka/DIPL/RESULTS/LINKS_6/rtabs   (16964 words)

Ray Tracing With Adaptive Supersampling in Object Space Thus, when a ray intersects a cover, it is in proximity to the boundary of an object, and the ray is split into two rays of reduced weight (one continues past the object, and the other hits the object). In ray bound tracing [13], a ray bound surrounding the ray is used to detect the proximity of the ray to the boundary of an object. In the simplest case, the central ray of the cone (which we will simply call the ray) can be used in the standard ray tracing illumination model to calculate a color for the pixel. www.cs.uaf.edu /~genetti/Research/Papers/GI93/GI.html   (4192 words)

MONTE CARLO RAY TRACING, ME 508 Term Project, Sezar Ercan   (Site not responding. Last check: 2007-11-04) Ray tracing was born with Appel’s algorithm which includes the generation of shadows. If the ray intersects the surface of an object, a number of rays originating at the intersection point might be spawned to determine the intensity at that point: a shadow ray for each light source in the scene, to determine if any objects are blocking the path between the light source and the intersection point. Since each ray must be checked against all objects, for a naive raytracer (with no speedup techniques) the time is proportional to the number of rays X the number of objects in the scene. attila.sdsu.edu /~ercan/me508project.htm   (3611 words)

Distrubuted ray tracing   (Site not responding. Last check: 2007-11-04) The basic idea of distributed ray tracing is to shoot a bunch of rays instead of a single ray, which are roughly the same direction (as if forming a narrow cone) and then take a weighted average to determine the final color. Traditional ray tracing produces images as if they have been shot using cameras of infinitely small paertures, resulting in all the objects being in focus, regardless of their distance from the viewpoint. The auxillary rays then have to pass through this point, while their origins are displaced a little about the intersection of primary ray and the screen, in the screen plane. www.cse.iitd.ernet.in /~csd01413/raytracer/distributed.html   (383 words)

Global illumination - Wikipedia, the free encyclopedia Radiosity, ray tracing, beam tracing, cone tracing, Path Tracing, metropolis light transport and photon mapping are examples of algorithms used in global illumination. These algorithms model diffuse inter-reflection which is a very important part of global illumination, however most of these (exluding radiosity) also model specular inter-reflection too which makes them more accurate algorithms to solve the lighting equation and provide a more realistic globally illuminated scene. The algorithms used to calculate the distribution of light energy between surfaces of a scene are closely related to heat transfer simulations performed using finite-element methods in engineering design. www.wikipedia.com /wiki/Global_illumination   (286 words)

Citations: Statistically optimized sampling for distributed ray tracing - Lee, Redner, Uselton (ResearchIndex)   (Site not responding. Last check: 2007-11-04) The process of intersecting a ray with the objects in the scene, and then determining which of the objects hit by the ray is closest to the ray origin is a costly one. The rays can still be treated independently if one is willing to redefine the manner in which the convolution region is defined (constructed) If we modify the definition of the convolution region to include that area of texture space inside the convex hull of a set of texture space point.... As this required minimal changes to the ray tracer and produced significantly less noticeable aliasing this approach became very popular [10, 11, 12] The general approach is to sample at a low rate and if the contrast or variance of neigbouring samples is high the sampling rate is increased in.... citeseer.lcs.mit.edu /context/60129/0   (4448 words)

CMPT 461 Project - Distributed Ray Tracing   (Site not responding. Last check: 2007-11-04) Distributing shadow rays across the surface of the extended light source. Ray tracing is computationally expensive, and efficiency will be a concern. Nick will likely be responsible for adding the first distributed ray tracing capabilities to the program; we will then work together to extend these capabilities, modeling additional phenomena such as soft shadows and depth of field. www.sfu.ca /~rbeier/461/proposal.html   (967 words)

Recursive Ray Tracing   (Site not responding. Last check: 2007-11-04) Ray tracing is recursive; secondary rays are followed recursively from primary rays Trace a reflection ray whose direction is determined by jittering a set of directions distributed according to a specular reflection function (use a lookup table directions) Trace a transmitted ray if the object is transparent; the direction is determined by jittering a set of directions distributed according to a specular transmission function (use a lookup table directions) www.cs.fit.edu /wds/classes/adv-graphics/raytrace/raytrace.html   (5185 words)

Distributed Ray Tracing - Andrew Zaferakis   (Site not responding. Last check: 2007-11-04) One basic principle in distributed ray tracing is shooting many rays and taking some sort of average of the colors for a final pixel value. The idea is to shoot rays around and through the center of the pixel and take an average of the colors returned from each ray. The jittering of the ray is similar to that used in the pixel sampling. www.cs.unc.edu /~andrewz/comp238/hw2   (1122 words)

Dave Strock > Graphics > Monte Carlo Ray Tracing   (Site not responding. Last check: 2007-11-04) Instead of simply sending one ray through the same spot of each pixel, monte carlo ray tracing introduces multiple rays per pixel as well as a "random" distribution of those rays over the area of the pixel. Each ray starts in the lower left corner of its grid, and then is randomly jittered by 0.25 in the x and y, giving a nice random distribution throughout the pixel. By randomly distributing multiple rays throughout the pixel area, and then averaging their returned colors, aliasing is replaced with noise. www.uwm.edu /~dtstrock/graphics/mcrt.html   (443 words)

Beyond3D - Which was nice.   (Site not responding. Last check: 2007-11-04) To do the super-sampling with distributed ray tracing, they'd cast multiple rays through a given pixel, take the average color of all of the rays, and then apply that average to the render. Instead of tracing specific points all in one direction from the light source as was traditionally done for soft shadows, they'd take and cross light paths putting the illumination in a variety of directions instead of towards one specific point. However, ray tracing takes a massive amount of power to render and simply cannot be done in real-time. www.beyond3d.com /articles/3dfxtech/index1_2.php   (581 words)

Distributed Ray Tracing tracing a ray according to the reflection angle produces sharp reflections Determine the focal point by sending a ray from the center of the lens to the point on the screen, then use the lens qualities to get the focal point. Jitter a point on the lens, then trace a ray from that point to the focal point of the original ray. rivit.cs.byu.edu /655/lecture_notes/distributed_ray.html   (674 words)

Distributed Interactive Ray Tracing (DIRT) - Parallel Visualization - Research - Scientific Computing and Imaging ...   (Site not responding. Last check: 2007-11-04) The data set is a time-step from the simulation of the Richtmyer-Meshkov instability produced when a shock intersects a contact discontinuity between two fluids.The data was provided by Lawrence Livermore National Lab. Ray tracing is inherently parallel, and we use standard image space parallelism for parallel acceleration. A unique aspect of our ray tracing solution is that the isovalue can be changed interactively. www.sci.utah.edu /research/dirt.html   (268 words)

Open Directory - Computers: Software: Graphics: 3D: Ray Tracing   (Site not responding. Last check: 2007-11-04) ACM Crossroads: Ray Tracing - Article on Ray Tracing in the student magazine of the ACM. Also known as ray casting, determines the visibility of surfaces by tracing imaginary rays of light from the viewer's eye to the objects in the scene. Ray Tracing Introduction from SIGGRAPH - A basic introduction to building a ray tracer, with some pointers to more advanced subjects at the end. dmoz.org /Computers/Software/Graphics/3D/Ray_Tracing   (934 words)

IntroDRT   (Site not responding. Last check: 2007-11-04) The difference between a normal Ray Tracer and a Distributed Ray Tracer is that in a Distributed Ray Tracer, instead of shooting just one ray through a pixel, we divide it into finer squares and shoot many rays through them. In a Distributed Ray Tracer, they are randomly 'jittered' or disturbed to give slightly off-accurate rays. Thus, in reality, the reflected/ refracted rays are actually never accurate due to such imperfections on the sufaces of objects. www.cse.ohio-state.edu /~ramakris/graphics/782/drtintro.html   (279 words)

Towards Real-Time Ray-Tracing of Combinatorial Solid Geometric Models   (Site not responding. Last check: 2007-11-04) Similarly, one ``sun visibility'' ray can be used both for shadow generation in the optical model, and in the solar loading calculation for the thermal model. By using the same set of rays that the optical rendering used and passing them to a set of thermal shader routines instead of the conventional optical shader routines, the scene radiance can be computed. Because of this, an irregular distribution of metal objects in the scene will not cause a workload imbalance among the 12 processors of one node, although it may cause some nodes to take longer to complete than others, based upon the metal content of that segment of the scene. ftp.arl.mil /~mike/papers/95cadsymp/realtime.html   (7525 words)

pvg,2003 IEEE Symposium on Parallel and Large-Data Visualization and Graphics Recently developed interactive ray tracing systems combine the high performance of todays CPUs with new algorithms and implementations to achieve a flexible and high-performance rendering system offering high-quality, but nonetheless interactive 3D graphics. However, due to its history in off-line rendering, interactive ray tracing is usually limited to static scenes and simple walkthroughs. In this paper, we present a simple and practical method that allows to interactively ray trace dynamic scenes in a distributed PC cluster environment. csdl.computer.org /comp/proceedings/pvg/2003/2091/00/20910011abs.htm   (268 words)

Distributed Ray Tracing   (Site not responding. Last check: 2007-11-04) Distributed ray tracing is an elegant technique that tackles many problems at once Stochastic ray tracing: distribute rays stochastically across pixel Distributed ray tracing: distribute rays stochastically across everything www.cs.virginia.edu /~cs551dl/lecture11/tsld016.htm   (29 words)

An Introduction To Ray Tracing In 1986 I was a professional researcher working in ray tracing, and I thought I should gather together some of my colleagues to present a SIGGRAPH course on ray tracing. We did, and An Introduction to Ray Tracing was the result. " An Introduction to Ray Tracing " is an excellent nuts and bolts summary of the science and practice of ray tracing. www.glassner.com /andrew/writing/books/irt.htm   (340 words)

CookPorter   (Site not responding. Last check: 2007-11-04) Many phenomena that are difficult or impossible with other techniques are simple with ray tracing, including shadows, reflections and refracted lights. By distributing the directions of the rays according to the analytic function they sample, ray tracing can incorporate fuzzy phenomena. This paper proposed that distributing the ray directions could help achieve many effects. www.cse.ohio-state.edu /~ramakris/graphics/782/CookPorter.htm   (153 words)

Whitted-Style Ray Tracing - Andrew Zaferakis   (Site not responding. Last check: 2007-11-04) After a ray has first intersected an object in the scene, a reflected and/or refracted ray must be computed. The origin and direction of the new ray is then casted through the scene to find the next closest intersection. Mathematically, the closest intersection is the same point on the object that the ray is being casted from. www.cs.unc.edu /~andrewz/comp238/hw1   (775 words)

Ray Tracing News Guide Jevans' Temporal Coherence for Ray Tracing, by Eric Haines Ray Tracing Roundtable at SIGGRAPH '94, by Eric Haines SIMD Parallel Ray Tracing, by George Kyriazis, Rick Speer www.etsimo.uniovi.es /povray/rtn   (3214 words)

Interactive Distributed Ray Tracing of Highly Complex Models - Wald, Slusallek, Benthin (ResearchIndex) Previous approaches relied on costly preprocessing for reducing the number of polygons that need to be rendered per frame... Interactive distributed ray tracing of highly complex models. 43 Interactive ray tracing for isosurface rendering - Parker, Shirley et al. citeseer.ist.psu.edu /510155.html   (517 words)

Antialiased Ray Tracing by Adaptive Progressive Refinement - Summary - 782 Lab3 - Distributed Raytracer - Vince Scheib ... Antialiased Ray Tracing by Adaptive Progressive Refinement - Summary - 782 Lab3 - Distributed Raytracer - Vince Scheib & Ryan Geiss Jittered sampling is achieved by placing the samples randomly within a cell on a regular grid. A poisson disk distribution is achieved by throwing a bunch of points into the pixel space, then nudging / replotting them until no two are within a certain distance. www.scheib.net /school/782/lab3/paper_sum2.html   (1091 words)

Try your search on: Qwika (all wikis)

About us   |   Why use us?   |   Reviews   |   Press   |   Contact us   Copyright © 2005-2007 www.factbites.com Usage implies agreement with terms.