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Radiosity 143 Radiosity solutions may be displayed in realtime via Lightmaps on current desktop computers with standard graphics acceleration hardware Advantages One of the advantages of the Radiosity algorithm is that it is relatively simple to explain and implement. This makes it a useful algorithm for teaching students about global illumination algorithms. A typical direct illumination renderer already contains nearly all of the algorithms (perspective transformations, texture mapping, hidden surface removal) required to implement radiosity. A strong grasp of mathematics is not required to understand or implement this algorithm. Limitations Typical radiosity methods only account for light paths of the form LD*E, i.e., paths which start at a light source and make multiple A modern render of the iconic Utah teapot. Radiosity was used for all diffuse illumination in this scene. diffuse bounces before reaching the eye. Although there are several approaches to integrating other illumination effects such as specular[3] and glossy [4] reflections, radiosity-based methods are generally not used to solve the complete rendering equation. Basic radiosity also has trouble resolving sudden changes in visibility (e.g., hard-edged shadows) because coarse, regular discretization into piecewise constant elements corresponds to a low-pass box filter of the spatial domain. Discontinuity meshing [5] uses knowledge of visibility events to generate a more intelligent discretization. Confusion about terminology Radiosity was perhaps the first rendering algorithm in widespread use which accounted for diffuse indirect lighting. Earlier rendering algorithms, such as Whitted-style ray tracing were capable of computing effects such as reflections, refractions, and shadows, but despite being highly global phenomena, these effects were not commonly referred to as "global illumination." As a consequence, the term "global illumination" became confused with "diffuse interreflection," and "Radiosity" became confused with "global illumination" in popular parlance. However, the three are distinct concepts. The radiosity method in the current computer graphics context derives from (and is fundamentally the same as) the radiosity method in heat transfer. In this context radiosity is the total radiative flux (both reflected and re-radiated) leaving a surface, also sometimes known as radiant exitance. Calculation of Radiosity rather than surface temperatures is a key aspect of the radiosity method that permits linear matrix methods to be applied to the problem.
Radiosity 144 References [1] " Modeling the interaction of light between diffuse surfaces (http:/ / www. cs. rpi. edu/ ~cutler/ classes/ advancedgraphics/ S07/ lectures/ goral. pdf)", C. Goral, K. E. Torrance, D. P. Greenberg and B. Battaile, Computer Graphics, Vol. 18, No. 3. [2] G Walton, Calculation of Obstructed View Factors by Adaptive Integration, NIST Report NISTIR-6925 (http:/ / www. bfrl. nist. gov/ IAQanalysis/ docs/ NISTIR-6925. pdf), see also http:/ / view3d. sourceforge. net/ [3] http:/ / portal. acm. org/ citation. cfm?id=37438& coll=portal& dl=ACM [4] http:/ / www. cs. huji. ac. il/ labs/ cglab/ papers/ clustering/ [5] http:/ / www. cs. cmu. edu/ ~ph/ discon. ps. gz External links • Radiosity Overview, from HyperGraph of SIGGRAPH (http:/ / www. siggraph. org/ education/ materials/ HyperGraph/ radiosity/ overview_1. htm) (provides full matrix radiosity algorithm and progressive radiosity algorithm) • Radiosity, by Hugo Elias (http:/ / freespace. virgin. net/ hugo. elias/ radiosity/ radiosity. htm) (also provides a general overview of lighting algorithms, along with programming examples) • Radiosity, by Allen Martin (http:/ / web. cs. wpi. edu/ ~matt/ courses/ cs563/ talks/ radiosity. html) (a slightly more mathematical explanation of radiosity) • RADical, by Parag Chaudhuri (http:/ / www. cse. iitd. ernet. in/ ~parag/ projects/ CG2/ asign2/ report/ RADical. shtml) (an implementation of shooting & sorting variant of progressive radiosity algorithm with OpenGL acceleration, extending from GLUTRAD by Colbeck) • ROVER, by Tralvex Yeap (http:/ / www. tralvex. com/ pub/ rover/ abs-mnu. htm) (Radiosity Abstracts & Bibliography Library) • Radiosity Renderer and Visualizer (http:/ / dudka. cz/ rrv) (simple implementation of radiosity renderer based on OpenGL) • Enlighten (http:/ / www. geomerics. com) (Licensed software code that provides realtime radiosity for computer game applications. Developed by the UK company Geomerics)
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3D Rendering PDF generated using th
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Image-based lighting 64 Image plane
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References Article Sources and Cont
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3D rendering 2 Non real-time Animat
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3D rendering 4 The shaded three-dim
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Ambient occlusion 6 ambient occlusi
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Ambient occlusion 8 • ShadeVis (h
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Anisotropic filtering 10 will only
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Beam tracing 12 Beam tracing Beam t
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Bilinear filtering 14 Are all true.
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Binary space partitioning 16 togeth
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Binary space partitioning 18 Other
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Binary space partitioning 20 [1] Bi
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Bounding interval hierarchy 22 Prop
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Bounding volume 24 bounding boxes b
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Bump mapping 26 Bump mapping Bump m
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CatmullClark subdivision surface 28
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CatmullClark subdivision surface 30
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Conversion between quaternions and
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Cube mapping 34 Advantages Cube map
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Cube mapping 36 Related A large set
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Diffuse reflection 38 2), or, of co
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Displacement mapping 40 Meaning of
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DooSabin subdivision surface 42 Ext
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False radiosity 44 False radiosity
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Geometry pipelines 46 Geometry pipe
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Global illumination 48 Rendering wi
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Gouraud shading 50 Gouraud shading
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Graphics pipeline 52 Graphics pipel
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Graphics pipeline 54 References 1.
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Hidden surface determination 56 imp
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High dynamic range rendering 58 Hig
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High dynamic range rendering 60 Ton
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High dynamic range rendering 62 Fro
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High dynamic range rendering 64 •
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Irregular Z-buffer 66 Applications
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Lambert's cosine law 68 than would
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Lambertian reflectance 70 Lambertia
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Level of detail 72 Well known appro
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Level of detail 74 Hierarchical LOD
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Newell's algorithm 76 Newell's algo
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Non-uniform rational B-spline 78 Us
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Non-uniform rational B-spline 80 of
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Non-uniform rational B-spline 82 ar
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Non-uniform rational B-spline 84 Ex
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Normal mapping 86 How it works To c
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OrenNayar reflectance model 88 Oren
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OrenNayar reflectance model 90 , ,
Page 97 and 98: Painter's algorithm 92 The algorith
Page 99 and 100: Parallax mapping 94 • Parallax Ma
Page 101 and 102: Particle system 96 A cube emitting
Page 103 and 104: Path tracing 98 History Further inf
Page 105 and 106: Path tracing 100 Scattering distrib
Page 107 and 108: Phong reflection model 102 Visual i
Page 109 and 110: Phong reflection model 104 Because
Page 111 and 112: Phong shading 106 Visual illustrati
Page 113 and 114: Photon mapping 108 Rendering (2nd p
Page 115 and 116: Photon tracing 110 Advantages and d
Page 117 and 118: Potentially visible set 112 • Can
Page 119 and 120: Potentially visible set 114 Externa
Page 121 and 122: Procedural generation 116 increases
Page 123 and 124: Procedural generation 118 • Softi
Page 125 and 126: Procedural generation 120 Reference
Page 127 and 128: Procedural texture 122 Self-organiz
Page 129 and 130: Procedural texture 124 References [
Page 131 and 132: 3D projection 126 The distance of t
Page 133 and 134: Quaternions and spatial rotation 12
Page 145 and 146: Radiosity 140 Overview of the radio
Page 147: Radiosity 142 This is sometimes kno
Page 151 and 152: Ray casting 146 the light will reac
Page 153 and 154: Ray tracing 148 Typically, each ray
Page 155 and 156: Ray tracing 150 independence of eac
Page 157 and 158: Ray tracing 152 On June 12, 2008 In
Page 159 and 160: Reflection 154 Reflection Reflectio
Page 161 and 162: Reflection 156 Glossy Reflection Fu
Page 163 and 164: Reflection mapping 158 Cube mapping
Page 165 and 166: Render Output unit 160 Render Outpu
Page 167 and 168: Rendering 162 • indirect illumina
Page 169 and 170: Rendering 164 Ray tracing Ray traci
Page 171 and 172: Rendering 166 Academic core The imp
Page 173 and 174: Rendering 168 • 1984 Distributed
Page 175 and 176: Retained mode 170 Retained mode In
Page 177 and 178: Scanline rendering 172 Comparison w
Page 179 and 180: Screen Space Ambient Occlusion 174
Page 181 and 182: Screen Space Ambient Occlusion 176
Page 183 and 184: Shadow mapping 178 Algorithm overvi
Page 185 and 186: Shadow mapping 180 Drawing the scen
Page 187 and 188: Shadow mapping 182 Further reading
Page 189 and 190: Shadow volume 184 There is also a p
Page 191 and 192: Shadow volume 186 The depth fail me
Page 193 and 194: Silhouette edge 188 Silhouette edge
Page 195 and 196: Specular highlight 190 Specular hig
Page 197 and 198: Specular highlight 192 normalized o
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Sphere mapping 194 Sphere mapping I
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Stencil codes 196 Stencil codes Ste
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Stencil codes 198 Stencils The shap
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Stencil codes 200 [7] Wellein, G et
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Subdivision surface 202 used a four
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Subsurface scattering 204 Subsurfac
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Subsurface scattering 206 External
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Surface normal 208 If a (possibly n
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Surface normal 210 Normal in geomet
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Texture filtering 212 Texture filte
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Texture mapping 214 Texture mapping
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Texture mapping 216 constant distan
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Texture synthesis 218 • Structure
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Texture synthesis 220 Pattern-based
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Texture synthesis 222 • Micro-tex
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UV mapping 224 A UV map can either
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Vertex 226 Polytope vertices are re
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Vertex Buffer Object 228 //Make the
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Vertex Buffer Object 230 GLuint sha
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Vertex Buffer Object 232 vertexes *
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Virtual actor 234 Virtual actor A v
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Virtual actor 236 exercises, and ev
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Volume rendering 238 Volume ray cas
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Volume rendering 240 Maximum intens
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Volume rendering 242 Image-based me
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Volumetric lighting 244 References
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Voxel 246 • Outcast, a game made
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Z-buffering 248 Z-buffering In comp
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Z-buffering 250 } } display COLOR a
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Z-fighting 252 Z-fighting Z-fightin
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Appendix 3D computer graphics softw
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3D computer graphics software 256
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3D computer graphics software 258
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3D computer graphics software 260 2
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Article Sources and Contributors 26
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Article Sources and Contributors 26
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Image Sources, Licenses and Contrib
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Image Sources, Licenses and Contrib
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