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Topic: Radiosity

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	Radiosity - Wikipedia, the free encyclopedia
		Radiosity is a global illumination algorithm used in 3D computer graphics rendering.
		Radiosity as a rendering method was introduced in 1984 by researchers at Cornell (C. Goral, K. Torrance, D. Greenberg and B. Battaile) in their paper "Modeling the interaction of light between diffuse surfaces".
		In order to simplify the calculations, the radiosity algorithm assumes that this amount is constant across the surfaces (perfect or ideal Lambertian surfaces); this means that to compute an accurate image, geometry in the scene description must be broken down into smaller areas, or patches, which can then be recombined for the final image.
	en.wikipedia.org /wiki/Radiosity (638 words)

	Radiosity - A Rendering Technique
		Early on, the radiosity algorithm was formulated in such a way that the distribution of the light among all the mesh elements had to be completely calculated before any useful results could be displayed on the screen.
		In 1988 this preprocessing portion of the radiosity algorithm was reformulated.
		This is because radiosity leaving a patch in any direction is influenced by the patch’s total radiosity, not by the directions from which its incoming energy was acquired.
	www.navs.8m.com /seminar/radiosity.html (7057 words)

	Radiosity Overview Part 3
		This second pass is viewpoint- dependent: specular highlights on a surface are dependent on the location of both the light and the viewer relative to the surface.
		Another variation on the basic diffuse radiosity solution adds the contribution of light passing through a participating medium, such as smoke, fog, or water vapor in the air.
		The viewpoint independence of the basic radiosity algorithm provides the opportunity for interactive "walkthroughs" of environments, as one intensity solution for an environment will serve as the base for any particular view of the environment.
	www.cse.unsw.edu.au /~cs9415/hypergraph/radiosity/overview_3.htm (781 words)

	Radiosity (Site not responding. Last check: 2007-11-04)
		Your own home, with its labyrinths of rooms, doors, and hallways exhibits radiosity at night when you turn on the bathroom nightlight: everyone in the rooms down the hallway know you are up because they can see just by the light reflected under their closed door.
		The longer the radiosity calculations are allowed to run, the less pronounced the patterning will be, and the more realistic the final rendered image will look.
		For example, a 128 X 64-pixel area in the radiosity map would correspond to a patch that is roughly twice as wide as it is high.
	www.hash.com /htmlhelp/HTMLHelp/mas00261.htm (575 words)

	DevMaster.net - Radiosity and BSP-Tree Rendering (Site not responding. Last check: 2007-11-04)
		The original idea for radiosity was formulated by a set of writers called Goral, Torrance, Battaile and Greenberg[1].
		To use the radiosity algorithm the world has to be divided into patches, where each patch represent a small part of the world.
		In the original idea of radiosity each light source in the scene should be considered as one or several patches.
	www.devmaster.net /articles/radiosity (1307 words)

	Radiosity Overview: Part 1
		As in thermal heat transfer, the basic radiosity method for computer image generation makes the assumption that surfaces are diffuse emitters and reflectors of energy, emitting and reflecting energy uniformly over their entire area.
		It should be noted the the basic radiosity method is viewpoint independent: the solution will be the same regardless of the viewpoint of the image.
		The "radiosity equation" describes the amount of energy which can be emitted from a surface, as the sum of the energy inherent in the surface (a light source, for example) and the energy which strikes the surface, being emitted from some other surface.
	www.siggraph.org /education/materials/HyperGraph/radiosity/overview_1.htm (702 words)

	VOLUME RADIOSITY
		are the radiosities of elements i and j, i.
		Two procedures are needed to determine the radiosity of elements in a scene: computation of form factors, and resolution of the matrix.
		As occurs with surface radiosity, the main advantage is that diffuse illumination is calculated in a form independent from the observer.
	www.inf.unisinos.br /~chris/radvol.html (3165 words)

	Radiosity Tests
		Radiosity looks good but screws up bump mapping but its fill effects are hard to achieve using fill lighting because they are nice and uneven.
		Ray tracing without radiosity produces hard shadows that really don't look that good but learning to control mapped shadows may be harder than dealing with radiosity.
		In the future I will probably choose radiosity where bump mapping is not important and ray tracing with area lights or light arrays to produce soft shadows when bump maps DO matter.
	www.computer-music.com /graphic/radiosity.htm (1084 words)

	Radiosity
		Radiosity is a method of rendering based on an detailed analysis of light reflections off diffuse surfaces.
		Radiosity is typically used to render images of the interior of buildings, and can achieve extremely photo-realistic results for scenes that are comprised of diffuse reflecting surfaces.
		The description of the radiosity model that follows is based on the original radiosity system developed by Goral et al.
	www.cs.wpi.edu /~matt/courses/cs563/talks/radiosity.html (1220 words)

	Gamasutra - Features - "Hemisphere Lighting With Radiosity Maps"
		Any kind of complex radiosity lighting could be modeled by encoding the surrounding light sources into an HDR (high dynamic range) cubemap, but it is impractical to update such a cubemap in realtime as large numbers of objects move around the world.
		The problem with using the radiosity map to encode shadows is that even if you darken down the ground color, the sky color is still a constant and therefore it won't be affected.
		The radiosity lighting works best if the sample position is offset along the vertex normal, but that is blatantly incorrect for shadowing, where the map should be sampled directly at the vertex position.
	www.gamasutra.com /features/20030813/hargreaves_01.shtml (1955 words)

	CPSC 591/691 NPR Radiosity Project Results - Lindsay, Brosz (Site not responding. Last check: 2007-11-04)
		When an architect is designing a room or a building she or he often has sketches produced that portray the lighting of the area being designed.
		Once we were able to render radiosity images successfully with POV-Ray it was time to begin the implementation of NPR functionality.
		Once the radiosity thresholding solution was in place an attempt to apply textures to a scene was initiated.
	pages.cpsc.ucalgary.ca /~lindsayd/591/final (1113 words)

	Radiosity Method
		In contrast to raytracing, all variants of the radiosity method have in common, that they seperate the process of shading surfaces and the visible-surface determination.
		Radiosity is very efficient to compute scenes up to a certain complexity with large numbers of light sources.
		Recently, the term radiosity is increasingly used to describe the general problem class of solving the global illumination model, and especially the complementary method of distributed raytracing.
	www.schorsch.com /kbase/glossary/radiosity.html (248 words)

	Research Images
		The radiosity solution took approximately 5 hours for 2,000 shots, and the image generation required 190 hours; each on a VAX8700.
		As the progressive radiosity solution executed, users could witness each of the baffles being illuminated from above, and then reflecting some of this light to the bottom of an adjacent baffle.
		A modified radiosity solution was ray traced to produce the specular highlights on the floor.
	www.graphics.cornell.edu /online/research (387 words)

	Dunno...
		The rate at which energy leaves a surface is called the 'radiosity' of a surface.
		During the later eighties and early nineties radiosity was a hot topic in 3D computer graphics.
		The Radiosity method is a typical example of a finite element method.
	download.blender.org /documentation/NaN_docs/Manual2.0/radiosity.html (1418 words)

	TGLTLSBFSSP: Radiosity
		We shall handle this in radiosity by saying that all patches emit light, but for most patches, their light emmision is zero.
		The first thing we'll have to deal with, in implementing radiosity, is to solve the problem of looking at the world from the point of view of each patch.
		The output of a radiosity renderer is an image where each pixel consists of three floating point values, one for each of red, green and blue.
	freespace.virgin.net /hugo.elias/radiosity/radiosity.htm (5612 words)

	Hierarchical Radiosity (Site not responding. Last check: 2007-11-04)
		The algorithm is based on the idea that the interaction between a large number of patches and a single patch can be represented as a single interaction with a large patch that represents the average radiosity of the original patches.
		Once the radiosity is gathered, the radiosity is "pushed" down the hierarchy and then "pulled" back up.
		The pull step averages the values of the radiosity of all of the children further down the hierarchy.
	www.cse.ohio-state.edu /~crawfis/cis782/Labs/FinalProjects/Radiosity_files/HierRadSummary.htm (333 words)

	RADIOSITY METHOD
		The radiosity method is based on the numerical solution of the shading equation by the finite element method.
		radiosities represent the light density of the surface on a given wavelength.
		Note that the first two steps of the radiosity method are independent of the actual view, and the form factor calculation depends only on the geometry of the surface elements.
	www.fsz.bme.hu /~szirmay/radiosit/node1.html (982 words)

	No Title (Site not responding. Last check: 2007-11-04)
		Radiosity is a theoretically rigorous method to the diffuse interaction problem in a closed environment
		Radiosity is the total rate at which energy leaves a surface; the sum of emitted and reflected energy (energy/unit time/unit area)
		Radiosity is well suited to this approach, the scene remains constant while the illumination is refined (like turning on a light with a dimmer switch)
	www.cs.fit.edu /wds/classes/adv-graphics/radiosity/radiosity.html (1639 words)

	GameDev.net - Radiosity Methods
		The disadvantage of hierarchical radiosity is that shadow boundaries tend to be jagged because subdivision occurs regularly and, therefore, does not follow the contour of the shadow.
		The accuracy to which radiosity is computed in the previous method is dependent on surface geometry.
		Galerkin radiosity is a means by which the integral equation for radiosity can be solved in terms of a basis set of non-constant functions across a surface
	www.gamedev.net /reference/articles/article873.asp (1255 words)

	Radiosity Shooting vs Gathering
		This applet shows students the graphic difference between two radiosity algorithms: shooting and gathering.
		The algorithms are animated for each iteration of the algorithms and the resulting visualization of a discretized scene and of its form factor matrix can be viewed as the animation progresses.
		If the shooting algorithm was selected, then choose to visualize either the total radiosity of a patch or the unshot radiosity of a patch.
	www.cs.brown.edu /exploratories/freeSoftware/repository/edu/brown/cs/exploratories/applets/radiositySVG/radiosity_shooting_vs_gathering_guide.html (213 words)

	Radiosity - Ray Tracing
		Deterministic radiosity algorithms, which have been used for radiosity for quite some time, are too slow for calculating global illumination for very complex scenes.
		In standard radiosity, the radiosity (illumination) is assumed to be constant over each surface element.
		Since the accuracy of the solution depends on the quality of the calculated mesh, it is important to generate a mesh that is adapted to the global illumination of the scene.
	www.cg.tuwien.ac.at /research/rendering/rays-radio (730 words)

	Amazon.com: Books: Radiosity and Realistic Image Synthesis (The Morgan Kaufmann Series in Computer Graphics) (Site not responding. Last check: 2007-11-04)
		The authors were very much involved in defining the radiosity method and they have developed and published some of the basic techniques and a lot of the advanced algorithms for the radiosity method and it shows.
		The radiosity method is quite complex and requires and a lot of acceleration techniques have been introduced during the late 80s and early 90s.
		This is a good radiosity text for a professor to reference a skilled student to (say a very advanced undergraduate or a graduate student).
	www.amazon.com /exec/obidos/tg/detail/-/0121782700?v=glance (1019 words)

	Gamasutra - Features - "Hemisphere Lighting With Radiosity Maps"
		Most significantly, the per-pixel radiosity lookups and sky color calculations can be replaced by a single CPU texture lookup at the center of the object, with the resulting sky and ground colors set as vertex shader constants, the hemisphere tween evaluated per vertex, and no work at all required in the pixel shader.
		Because the radiosity map is only a two dimensional image, there will obviously be problems with environments that include multiple vertical levels.
		Such cases can be handled by splitting the world into layers, with a different radiosity map for each, but this lighting model is not well suited to landscapes with a great deal of vertical complexity.
	www.gamasutra.com /features/20030813/hargreaves_02.shtml (483 words)

	Publisher description for Library of Congress control number 93072454
		Radiosity and Realistic Image Synthesis offers the first comprehensive look at the radiosity method for image synthesis and the tools required to approach this elusive goal.
		The algorithms that have been developed to implement the radiosity method ranging from environment subdivision to final display are discussed.
		Extensions to the basic radiosity method to include glossy surfaces, fog or smoke, and realistic light sources are also described.
	www.loc.gov /catdir/description/els032/93072454.html (392 words)

	CGarchitect.com Forums - Mental Ray = Good , Radiosity = Bad
		After a year of playing around with Radiosity in Max 5 and 6 I've FINALLY realised that Mental Ray is a far more efficient / predictable renderer.
		I've been working with Radiosity for almost 3 years, with mental ray GI for 4-5, and with Light Tracer for 2.5.
		Radiosity, even with photometric lights, is the quickest way to a very good lighting solution.
	www.cgarchitect.com /vb/printthread.php?t=5888 (480 words)

	Resources
		Radiosity and Global Illumination by Francois X. Sillion and Claude Puech (1994) is a 250-page graduate-level textbook on the mathematics of synthesizing photorealistic images using radiosity methods.
		Radiosity in computer graphics is often thought of as a relatively recent innovation.
		Ziro Yamauti presented radiosity in terms of Fredholm integrals of the second kind, a mathematical formalism that did not appear in the computer graphics radiosity literature until its rediscovery by Paul Heckbert in 1991.
	www.helios32.com /resources.htm (1513 words)

	Reference Material - Radiosity (Site not responding. Last check: 2007-11-04)
		Radiosity is the level of light reflected off of or scattered by light falling across surfaces.
		Radiosity is to efficient lighting what shadow mapping is to efficient shadowing.
		Radiosity settings are located under the Global Illumination panel under the Settings Tab within Layout or through any light properties also give access to this panel.
	art-design.smsu.edu /yarberry/Courses/Reference/Radiosity (420 words)

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