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	Gouraud shading - Wikipedia, the free encyclopedia
		Gouraud shading is a method used in computer graphics to simulate the differing effects of light and colour across the surface of an object.
		The basic principle behind the method is to calculate the surface normals at the vertices of polygons in a 3D computer model.
		The lighting calculation used by Gouraud was based on the Lambertian diffuse lighting model.
	en.wikipedia.org /wiki/Gouraud_shading (387 words)

	Lighting, Color, and Materials
		OpenGL models the reflected component of a light as shininess, the diffuse scattered component of a light as diffuse, and general light energy from other sources as ambient.
		The reflected ray angle is equal to the incident ray angle (the incomming light ray) with respect to the local normal vector.
		Note that because the lighting model uses products between light and material parameters for computation of the light energy factors, and multiplication is commutative, equivalent visual results can be obtained by holding the material constant and varying the light parameters.
	www.bol.ucla.edu /~dremba/3dg_lighting.htm (1954 words)

	Lambertian diffuse lighting model: Definition and Links by Encyclopedian.com - All about Lambertian diffuse lighting ...
		After Johann Heinrich Lambert, from Photometria published in 1760, the Lambertian diffuse lighting model describes a simple non shiny surface where any incident light is reflected evenly in all directions after modulation by the surface's reflectivity.
		It should be noted that the part of this model that assumes all light reflected from a surface is reflected evenly in all directions is a very approximate equation when compared to how real surfaces reflect light and is only even approximately correct for very smooth matte surfaces.
		In some forms it remains popular for diffuse lighting calculations, particularly in 3D computer graphics.
	www.encyclopedian.com /la/Lambertian-diffuse-lighting-model.html (154 words)

	Gamasutra - Interactive 3D Lighting in Sprites Rendering
		Recent research in clouds rendering includes sprite rendering as a function of light [4] which uses a directional light and distance attribute from the center of the cloud to achieve normal direction of the sprite.
		It is based on Lambertian rule [2] for diffuse lighting and a normal attribute for each particle.
		Once diffuse shading is achieved, we multiply the result in the color map and the rendering process blends the sprites using their alpha values.
	www.gamasutra.com /gdc2005/features/20050308/erez_01.shtml (1730 words)

	VEX Shading Contexts
		Inside the surface context, it is possible to loop through all light sources in the scene computing their illumination and shadows.
		With a roughness of 0, the Oren-Nayar lighting model is equivalent to the Lambertian model.
		Light shaders will get called from surface or fog shaders to compute the illumination from a given light source.
	oldsite.vislab.usyd.edu.au /users/manuals/sfx/houdini/vex/shading.html (2989 words)

	Diffuse Reflection (Site not responding. Last check: 2007-09-15)
		The intensity does however depend on the light source's orientation relative to the surface, and it is this property that is governed by Lambert's law.
		The angle between the surface normal and the incoming light ray is called the angle of incidence and we can express a intensity of the light in terms of this angle.
		A value of zero means that all of the light is absorbed and converted to heat; a value of one is an ideal reflector.
	www.cs.nps.navy.mil /people/faculty/capps/iap/class3/ads/diffuse.html (346 words)

	Diffuse lighting - Vision Systems Design - Using telecentric lenses in inspection systems (Site not responding. Last check: 2007-09-15)
		General Diffuse Lighting: Lighting from luminaires that distribute 40% to 60% of its emitted lumens downward and the balance upward.
		Diffuse light produced from this technique is perfect for reproducing human skin This is known as diffuse light.
		Diffuse light is sunlight that is reflected off of clouds, the ground, Diffuse light cannot be focused by the optics of a concentrator PV system.
	infoindexes.com /?q=diffuse-lighting (438 words)

	Lighting (Site not responding. Last check: 2007-09-15)
		Ambient Light: We assume a constant amount of light is reflected throughout the environment.
		Diffuse Light: For a shaded object, we know that object’s illumination varies from one part of it’s surface to another depending on the position of an undirected (point) light source.
		Specular Light (reflection): Shiny surfaces reflect light in the direction of reflection R, which is L mirrored about N. The result is a highlight dependent on the viewing vector V. p
	home.winsocket.com /~dreamsir/eric/dreamsir/Lighting.htm (130 words)

	Diffuse Colour (Site not responding. Last check: 2007-09-15)
		An instance of this DRM class specifies the diffuse reflectance component of a instance.
		A Colour> instance is dependent on the angle of the lit environmental object to the light source but independent of the angle of the lit environmental object to the observer.
		When a beam of light is reflected from such a surface, the reflected ray is diffused to cover an area, the size of which is inversely proportional to the cosine of the angle that the beam makes with the surface normal.
	www.sedris.org /sdk_4.0.1/docs/tech/drm/classes/DiffuseColour.htm (211 words)

	Virtualized OpenGL Light Sources for Efficient Multi-Light Source Lighting
		Virtualized light sources have the disadvantage of introducing overhead due to lighting state changes and may not be able to completely handle (rare?) situations where more than 8 light sources (or whatever higher limit exists) are truly needed to correctly capture an intricate lighting effect.
		Basically, Lambert's Law explains that the diffuse light bouncing off a diffuse surface is proprotional to the cosine of the angle between the normal of the surface and the direction of the light source.
		The Lambertian-based approach does a better job determining what light sources are really going to contribute to the lighting of the sphere based on not just their distance from the sphere, but also the nature of diffuse reflections from the surface.
	meru.rnet.missouri.edu /courses/cecs361/projects/ws98/solar_simple/final/VirtualizedLights.html (1627 words)

	Gouraud shading -- Facts, Info, and Encyclopedia article (Site not responding. Last check: 2007-09-15)
		The lighting calculation used by Gouraud was based on the (Click link for more info and facts about Lambertian diffuse lighting model) Lambertian diffuse lighting model.
		To complete the shading, the (An iconic mental representation) image is filled by lines drawn across the image that interpolate between the previously calculated edge intensities.
		For instance, the white shiny spot on the surface of an apple (called a (Click link for more info and facts about specular highlight) specular highlight) is highly dependent on the normal within that spot.
	www.absoluteastronomy.com /encyclopedia/G/Go/Gouraud_shading.htm (465 words)

	Basic Illumination Model
		Ia is the intensity of ambient light, assumed to be constant for all objects, and ka is the ambient-reflection coefficient.
		, the angle of incidence of the light.
		The response of a receptor to light is inhibited by its adjacent receptors in inverse relation to the distance to the adjacent receptor.
	www.cs.nps.navy.mil /people/faculty/capps/4473/projects/01Summer/shading/Eray-LongVersion.htm (1515 words)

	MQP (Site not responding. Last check: 2007-09-15)
		L_d is the intensity of the diffuse light source (the strength of the light being used).
		The basis of his model is the shinier the material the surface of the object is made of, the brighter the specular highlight is. To generate specular highlights, he used a Gaussian curve generated by a cosine function raised to "n", where "n" relates to the "shininess" of the object.
		L_d is the intensity of the diffuse light source (the strength of the light being used for diffuse lighting).
	www.cs.wpi.edu /~emmanuel/research/appearance/Bravado (2472 words)

	Sheepish Software (Site not responding. Last check: 2007-09-15)
		nophong is a general lighting model replacement for lightwave.
		nophong is primarily a platform for experimenting with these models as in many situations empirical models provide adequate results (especially in the context of CG) without the overhead of computing 'real' and hence complex equations.
		currently nophong implements an improvement over the lambertian diffuse assumption that energy is reflected equally in all directions.
	www.sabermann.uklinux.net /nophong.php3 (204 words)

	Diffuse Color (Site not responding. Last check: 2007-09-15)
		Surfaces exhibiting only diffuse reflection (also known as Lambertian reflection) are dull, matte surfaces that appear equally bright from all viewing angles.
		When a beam of light is reflected from such a surface, the reflected ray is diffused to cover an area whose size is inversely proportional to the cosine of the angle that the beam makes with the surface normal.
		Diffuse reflection provides what is known as "shape from shading" information to visual perception; that is, for a surface composed of a single substance and illuminated by a single light source, the shading of the object can be used to compute its surface normals (i.e., its shape).
	www.sedris.org /stc/2001/tu/drm_api/drm/DiffuseColor.htm (199 words)

	Physically Accurate Lighting Simulation / Lightscape System
		The absence of parallel light source in Lightscape is compensated partially by mechanism of daylight usage in a model (the North direction, Latitude and Longitude of a model location, and the Greenwich Mean Time should be specified, ref.
		In LVS the overall character of the material is determined by the combination of the specular and the diffuse components (ref. to ch.2, p.48).
		To be precise, material definition consists of diffuse and specular colors, specular reflectivity that causes reflective effects during ray tracing, relative transparency that produces colored shadows based on the material's diffuse color, and index of refraction (ref. to Reference Guide, p.178).
	www.keldysh.ru /pages/cgraph/articles/pals/lightscape.htm (779 words)

	Gouraud shading -- Facts, Info, and Encyclopedia article (Site not responding. Last check: 2007-09-15)
		Gouraud shading is a method used in (The pictorial representation and manipulation of data by a computer) computer graphics to simulate the differing effects of light and colour across the surface of an object.
		Gouraud shading is much less processor intensive than (Click link for more info and facts about Phong shading) Phong shading, but does not calculate all desirable lighting effects as accurately.
		Despite the drawbacks, Gouraud shading is much superior to (Click link for more info and facts about flat shading) flat shading which requires significantly less processing than Gouraud, but gives low-polygon models a sharp, faceted look.
	www.absoluteastronomy.com /encyclopedia/g/go/gouraud_shading.htm (465 words)

	The RenderMan Academy -
		A well identified problem in CG rendering is the lack of light energy that bounces around the scene and contributes to the illumination of objects.
		This model is ideal for calculating the diffuse component of a surface because it is really fast and easy to use, but as you see in the picture above the fade from lit to dark areas is very fast.
		With the use of an illuminance loop the intensity or each light is added to the currently shaded point P. The angle between the surface normal N and the light vector L dictates how much the light will contribute to the shading.
	www.rendermanacademy.com /docs/WrapDiffuse.htm (545 words)

	Simple Illumination Model
		Light that passes and refracts through transparent objects such as water or a glass vase
		L, a vector from the surface position that points towards the light source.
		L coincide, the light source is directly overhead.
	csis.pace.edu /~marchese/CG/Lect15/cg_l15.htm (696 words)

	Diffuse Reflectance Model ['95] (Site not responding. Last check: 2007-09-15)
		The surface patch imaged by each sensor detector is modeled as a collection of numerous long symmetric V-shaped cavities; each cavity has two planar Lambertian facets with opposing normals, facet normals are free to deviate from the mean surface normal, and all facets on the surface have the same albedo.
		The developed model is a generalization of the popular Lambertian model, which is simply an extreme case with roughness equal to zero.
		This reflectance model is now available as a lighting model in a variety of commercial rendering packages such as Maya and 3DStudioMax.
	www1.cs.columbia.edu /CAVE/research/demos/new/diffusereflectancemodel.html (458 words)

	CGTalk - Lighting crit please :)
		Similarly for the lighting, the glowing light coming out of the machine is the main focus of the picture, so try switching everything off except that.
		I think the second to last picture was the most interseting: try using many soft shadowed light sources of slightly varying colours and intensities inside the machine to cast interesting light and shadow on the walls.
		The lights should be intenser but fall off way faster, keeping the room corners very dark but with bright pools of light.
	forums.cgsociety.org /showthread.php?p=2239383 (1620 words)

	ray tracing projects - jasonwaltman.com
		Added support for triangles, lighting of Lambertian (total diffuse) surfaces, shadows, and viewing to the basic ray tracer of assignment 1.
		Instead of modeling, for example, an ellipsoid, we can create one by simply rendering a sphere with some transformation matrix applied to the rays that hit the it.
		Continuing with the real camera model, we allow objects to move over time by specifying a start and end point, and start and end times.
	www.jasonwaltman.com /graphics/raytracing.html (491 words)

	The Cosine Lobe Model. (Site not responding. Last check: 2007-09-15)
		First, it contains the Lambertian model of perfectly diffuse reflectance when the Phong exponent is null.
		It is capable of representing more generalized diffuse behavior, whose reflectance decreases exponentially according to the azimuthal angle theta.
		The classical Phong model has several difficulties -- among them, the apparent brightness decreases for glancing angles, exactly the opposite of the effect observed in nature.
	www.cs.utah.edu /~wmartin/lafortune (276 words)

	Simple Illumination Model
		Gouraud shading (Henri Gouraud, 1971) is used to achieve smooth lighting on low-polygon surfaces using the Lambertian diffuse lighting model.
		Lighting computations are then performed to produce intensities at vertices.
		Lighting computations are then performed to produce intensities at positions along scanlines.
	csis.pace.edu /~marchese/CG/Lect10New/cg_l10new.htm (974 words)

	Physically Accurate Lighting Simulation / Specter System
		In addition, several types of standard light sources are available: point, linear, rectangular, circular, for which a goniometrical diagram can be assigned that describes directional distribution of emitted light.
		It simulates physical phenomena of scattering the light in water drops around the light sources (ref. to ch.3.2, ch.3.6.7, and ch.5.4.2).
		This is a very important property as it allows to obtain accurate simulation results for models involving arbitrary long sequences of specular and diffuse interreflections, which is typical for some technical devices such as plane light emitters, and user even have not to bother about the complexity of light paths in a model in question.
	www.keldysh.ru /pages/cgraph/articles/pals/specter.htm (776 words)

	Untitled Document (Site not responding. Last check: 2007-09-15)
		The classic lamertian lighting model sometimes cannot produce acceptable result because that diffuse falls off too fast.
		Lamert's diffuse is mutiplied by the dot-production of Surface shading normal(N) and Incoming light ray direction(L).
		Those upper two image are from same model lighted by a spot light.
	zj.deathfall.com /wrappeddiffuse.htm (184 words)

	Seminar - GRASP Lab@Penn
		First, we show that almost all the appearance of Lambertian objects is determined by the first nine components of the lighting when represented as spherical harmonics; these correspond to the diffuse components of lighting.
		Given a 3D model, this allows us to analytically derive a 9D linear subspace that can be used to build efficient object recognition algorithms.
		We use this model to identify objects such as wine glasses, whose appearance is characterized by little more than highlights.
	www.grasp.upenn.edu /seminar/AY-2003/David_Jacobs.html (422 words)

	MODEL (Site not responding. Last check: 2007-09-15)
		Search the MODEL Family Message Boards at Ancestry.com (if available).
		Search the MODEL Family Resource Center at RootsWeb.com (if available).
		Find graves of people named MODEL at Find-a-Grave.com (or add one that you know).
	www.worldhistory.com /surname/US/M/MODEL.htm (73 words)

	cs184 assignment 9 Texturing, Lighting, and Rendering
		Because this integral is complex usually the result is approximated by representing the area light source as a number of small patches over which the direction from light source to the point changes little, or completely discretizing the light source into a collection of point light sources on the surface of the area light.
		There are examples of area light sources in the SLIDE files for the examples discussed in the summary.
		We assume the facets are lambertian surfaces and that they are small enough so that light striking them from a nearby light source is coming in at the same angle over the entire facet (note this is not true for a large polygon!).
	www.cs.berkeley.edu /~ug/slide/pipeline/assignments/as9 (5239 words)

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