## Using the Modified Phong Reflectance Model for Physically Based Rendering (1994)

Citations: | 26 - 0 self |

### BibTeX

@TECHREPORT{Lafortune94usingthe,

author = {Eric P. Lafortune and Yves D. Willems},

title = {Using the Modified Phong Reflectance Model for Physically Based Rendering},

institution = {},

year = {1994}

}

### Years of Citing Articles

### OpenURL

### Abstract

This text discusses a few aspects of reflectance models in physically based rendering: ffl The first section presents the definition of the bidirectional reflection distribution function (brdf) of a surface and its physical properties. ffl On a more practical level, the next section discusses models to represent brdfs and their desired properties in general for Monte Carlo algorithms. ffl The third section goes into details about a specific reflectance model, the modified Phong brdf, with its definition, its properties and its use. We show how this model can be correctly integrated in importance sampling schemes for physically based Monte Carlo rendering algorithms. ffl The fourth section is devoted to alternative parameter spaces in which reflectance models can be sampled, either deterministically or stochastically. ffl The last section discusses an important implementational issue, more specifically the problem of verifying the implementation of a reflectance model. Keywords : ...

### Citations

466 |
Illumination for computer generated pictures
- Phong
- 1975
(Show Context)
Citation Context ...tion [15]. 3 3 The modified Phong reflectance model 3.1 Definition In 1975 Phong introduced a shading model which returns a colour for a point on a surface in the presence of some point light sources =-=[16]-=-. While the model does not have a physical basis and cannot be used as a brdf as it is, a physically plausible brdf which is very similar to the shading model is commonly used in rendering algorithms ... |

384 |
Measuring and modeling anisotropic reflection
- WARD
- 1992
(Show Context)
Citation Context ...osity method which assumes that all surfaces are Lambertian (i.e. perfectly diffuse). The model may also be more elaborate and flexible, allowing for specular and glossy reflections, anisotropy, etc. =-=[2, 3, 4, 5, 6]-=-. It should of course be physically plausible. If not, algorithms that use it may not converge to a correct solution or not converge at all. 2.2 Desired practical properties Monte Carlo algorithms for... |

375 |
A reflectance model for computer graphics
- Cook, Torrance
- 1981
(Show Context)
Citation Context ...osity method which assumes that all surfaces are Lambertian (i.e. perfectly diffuse). The model may also be more elaborate and flexible, allowing for specular and glossy reflections, anisotropy, etc. =-=[2, 3, 4, 5, 6]-=-. It should of course be physically plausible. If not, algorithms that use it may not converge to a correct solution or not converge at all. 2.2 Desired practical properties Monte Carlo algorithms for... |

158 | A comprehensive physical model for light reflection
- Xiao, Torrance, et al.
- 1991
(Show Context)
Citation Context ...osity method which assumes that all surfaces are Lambertian (i.e. perfectly diffuse). The model may also be more elaborate and flexible, allowing for specular and glossy reflections, anisotropy, etc. =-=[2, 3, 4, 5, 6]-=-. It should of course be physically plausible. If not, algorithms that use it may not converge to a correct solution or not converge at all. 2.2 Desired practical properties Monte Carlo algorithms for... |

136 | Bi-directional path tracing
- Lafortune, Willems
- 1993
(Show Context)
Citation Context ...ften has to use an approximating pdf though. This type of importance sampling is commonly used in stochastic ray tracing where new directions have to be sampled recursively at each intersection point =-=[7, 8, 9, 10, 11, 12, 13]-=-. ffl Some algorithms require that brdf (times the cosine factor) can be integrated easily over the hemisphere to obtain the total hemispherical reflectivitysae. Although the brdf can always be integr... |

88 |
Particle transport and image synthesis
- Arvo, Kirk
(Show Context)
Citation Context ...vity also determines whether the model is energy-conserving or not. One application is Russian roulette where the relative probabilities to reflect or absorb an incoming ray at a surface depend on it =-=[14, 9, 10, 11, 12, 13]-=-. Another application is the use of an ambient term times the brdf as a control variate for the rendering equation [15]. 3 3 The modified Phong reflectance model 3.1 Definition In 1975 Phong introduce... |

71 | Physically based lighting calculations for computer graphics
- Shirley
- 1990
(Show Context)
Citation Context ...ften has to use an approximating pdf though. This type of importance sampling is commonly used in stochastic ray tracing where new directions have to be sampled recursively at each intersection point =-=[7, 8, 9, 10, 11, 12, 13]-=-. ffl Some algorithms require that brdf (times the cosine factor) can be integrated easily over the hemisphere to obtain the total hemispherical reflectivitysae. Although the brdf can always be integr... |

70 |
Computation of global illumination by Monte Carlo simulation of the particle model of light
- Pattanaik, Mudur
- 1992
(Show Context)
Citation Context ...ften has to use an approximating pdf though. This type of importance sampling is commonly used in stochastic ray tracing where new directions have to be sampled recursively at each intersection point =-=[7, 8, 9, 10, 11, 12, 13]-=-. ffl Some algorithms require that brdf (times the cosine factor) can be integrated easily over the hemisphere to obtain the total hemispherical reflectivitysae. Although the brdf can always be integr... |

68 | Making shaders more physically plausible
- Lewis
- 1993
(Show Context)
Citation Context ... total hemispherical reflectivity: ae(x; \Theta i ) = Z \Omega x f r (x; \Theta i ; \Theta o ) cos` o d! os1; 8x; \Theta i Functions conforming to these constraints can be called physically plausible =-=[1]-=-. 2 2 Reflectance models 2.1 Definition A reflectance model is a practical representation for some set of brdfs. Any implementation of a global illumination algorithm uses a reflectance model. It may ... |

53 | A customizable reflectance model for everyday rendering
- SCHLICK
- 1993
(Show Context)
Citation Context |

32 |
Monte Carlo light tracing with direct computation of pixel intensities
- Dutre, Lafortune, et al.
- 1993
(Show Context)
Citation Context |

29 |
Computational Methods for Global Illumination and Visualisation of Complex 3D Environments
- Pattanaik
- 1993
(Show Context)
Citation Context |

27 | Distribution ray tracing: theory and practice
- Shirley, Wang
- 1992
(Show Context)
Citation Context |

23 |
A theoretical framework for physically based rendering
- Lafortune, Willems
- 1994
(Show Context)
Citation Context |

19 | A survey of shading and reflectance models
- Schlick
- 1994
(Show Context)
Citation Context |

11 | The ambient term as a variance reducing technique for Monte Carlo ray tracing
- LAFORTUNE, WILLEMS
- 1994
(Show Context)
Citation Context ...o reflect or absorb an incoming ray at a surface depend on it [14, 9, 10, 11, 12, 13]. Another application is the use of an ambient term times the brdf as a control variate for the rendering equation =-=[15]-=-. 3 3 The modified Phong reflectance model 3.1 Definition In 1975 Phong introduced a shading model which returns a colour for a point on a surface in the presence of some point light sources [16]. Whi... |