## Precomputed Radiance Transfer for Real-Time Rendering in Dynamic, Low-Frequency Lighting Environments (2002)

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Venue: | ACM Transactions on Graphics |

Citations: | 355 - 23 self |

### BibTeX

@INPROCEEDINGS{Sloan02precomputedradiance,

author = {Peter-pike Sloan and Jan Kautz and John Snyder},

title = {Precomputed Radiance Transfer for Real-Time Rendering in Dynamic, Low-Frequency Lighting Environments},

booktitle = {ACM Transactions on Graphics},

year = {2002},

pages = {527--536}

}

### Years of Citing Articles

### OpenURL

### Abstract

We present a new, real-time method for rendering diffuse and glossy objects in low-frequency lighting environments that captures soft shadows, interreflections, and caustics. As a preprocess, a novel global transport simulator creates functions over the object's surface representing transfer of arbitrary, low-frequency incident lighting into transferred radiance which includes global effects like shadows and interreflections from the object onto itself. At run-time, these transfer functions are applied to actual incident lighting. Dynamic, local lighting is handled by sampling it close to the object every frame; the object can also be rigidly rotated with respect to the lighting and vice versa. Lighting and transfer functions are represented using low-order spherical harmonics. This avoids aliasing and evaluates efficiently on graphics hardware by reducing the shading integral to a dot product of 9 to 25 element vectors for diffuse receivers. Glossy objects are handled using matrices rather than vectors. We further introduce functions for radiance transfer from a dynamic lighting environment through a preprocessed object to neighboring points in space. These allow soft shadows and caustics from rigidly moving objects to be cast onto arbitrary, dynamic receivers. We demonstrate real-time global lighting effects with this approach.

### Citations

1213 |
An algorithm for vector quantizer design
- Linde, Buzo, et al.
- 1980
(Show Context)
Citation Context ...ent radiance field over an object. Note the improved locality of lighting in (c) compared to (a) when the lighting is sampled at the 8 points in (b) rather than at the object center. point) algorithm =-=[28]-=- as a preprocess, given a desired number of points as input. This produces a representative set of points Pi near O and distributed uniformly over it where incident lighting can be sampled at run-time... |

713 | The rendering equation
- KAJIYA
- 1986
(Show Context)
Citation Context ...nterreflections are important effects in realistic image synthesis. Unfortunately, general methods for integrating over large-scale lighting environments [8], including Monte Carlo ray tracing [7][21]=-=[25]-=-, radiosity [6], or multi-pass rendering that sums over multiple point light sources [17][27][36], are impractical for real-time rendering. Real-time, realistic global illumination encounters three di... |

321 | Rendering synthetic objects into real scenes: Bridging traditional and image-based graphics with global illumination and high dynamic range photography
- Debevec
- 1998
(Show Context)
Citation Context ...ighting from area sources, soft shadows, and interreflections are important effects in realistic image synthesis. Unfortunately, general methods for integrating over large-scale lighting environments =-=[8]-=-, including Monte Carlo ray tracing [7][21][25], radiosity [6], or multi-pass rendering that sums over multiple point light sources [17][27][36], are impractical for real-time rendering. Real-time, re... |

308 | Radiosity and Realistic Image Synthesis
- Cohen, Wallace
- 1993
(Show Context)
Citation Context ...are important effects in realistic image synthesis. Unfortunately, general methods for integrating over large-scale lighting environments [8], including Monte Carlo ray tracing [7][21][25], radiosity =-=[6], -=-or multi-pass rendering that sums over multiple point light sources [17][27][36], are impractical for real-time rendering. Real-time, realistic global illumination encounters three difficulties – it... |

308 |
M.: Acquiring the reflectance field of a human face
- Debevec, Hawkins, et al.
- 2000
(Show Context)
Citation Context ... fields over surfaces to allow viewpoint change but restrict lighting changes to the directional intensity distribution of an existing set of non-area light sources in diffuse scenes. Debevec, et al. =-=[9] r-=-elight faces using a directional light basis. Real-time rendering requires a fixed view. Shadow maps, containing depths from the light source’s point of view, were first used by Williams [43] to sim... |

277 |
Angular Momentum in Quantum Mechanics
- Edmonds
- 1957
(Show Context)
Citation Context ... index) represent low-frequency basis functions over the sphere. The basis functions for band l reduce to polynomials of order l in x, y, and z. Evaluation can be done with simple recurrence formulas =-=[13][-=-44]. Projection and Reconstruction Because the SH basis is orthonormal, a scalar function f defined over S can be projected into its coefficients via the integral m m fl = Ú f() s yl () s ds (1) Thes... |

232 |
D.: A Ray Tracing Solution for Diffuse Interreflection
- WARD, RUBINSTEIN, et al.
- 1988
(Show Context)
Citation Context ...effects. Finally, our neighborhood transfer extends these ideas to cast shadows, caustics, and reflections. Caching onto diffuse receivers is useful for accelerating global illumination. Ward et. al. =-=[41]-=- perform caching to simulate diffuse interreflection in a ray tracer. Photon maps [21] also cache but perform forward ray tracing from light sources rather than backwards from the eye, and handle spec... |

231 | A practical model for subsurface light transport
- Jensen, Marschner, et al.
- 2001
(Show Context)
Citation Context ...space, allowing cast soft shadows and caustics onto arbitrary receivers. In future work, we want to apply precomputed transfer to more sophisticated transport models, especially subsurface scattering =-=[22]-=-. We believe the smoothness of exiting radiance produced by this model makes it particularly suitable for SH-parameterized transfer. It would also be valuable to combine existing shadowing techniques ... |

228 |
Towards Image Realism with Interactive Update Rates in Complex Virtual Building Environments
- Airey, Rohlf, et al.
- 1990
(Show Context)
Citation Context ...ng. 2. Related Work Scene relighting precomputes a separate global illumination solution per light source as we do; linear combinations of the results then provide limited dynamic effects. Early work =-=[2][11]-=- adjusts intensities of a fixed set of sources and is not intended to fit general lighting environments. Nimeroff, et al. [33] precompute a “steerable function” basis for general skylight illumina... |

198 | Rendering antialiased shadows with depth maps - Reeves, Salesin, et al. - 1987 |

180 | Instant radiosity
- KELLER
(Show Context)
Citation Context ...thods for integrating over large-scale lighting environments [8], including Monte Carlo ray tracing [7][21][25], radiosity [6], or multi-pass rendering that sums over multiple point light sources [17]=-=[27][3-=-6], are impractical for real-time rendering. Real-time, realistic global illumination encounters three difficulties – it must model the complex, spatially-varying BRDFs of real materials (BRDF compl... |

171 |
Environment mapping and other applications of world projections
- Greene
- 1986
(Show Context)
Citation Context ...ampling an analytic or tabulated BRDF at a few points, but becomes intractable for large light sources. A second line of research samples radiance and preconvolves it with kernels of various sizes [5]=-=[14]-=-[19][24][34]. This solves the light integration problem but ignores light transport complexities like shadows since the convolution assumes the incident radiance is unoccluded and unscattered. Finally... |

150 | The Accumulation Buffer: Hardware Support for High-Quality Rendering
- Haeberli, Akeley
- 1990
(Show Context)
Citation Context ...l methods for integrating over large-scale lighting environments [8], including Monte Carlo ray tracing [7][21][25], radiosity [6], or multi-pass rendering that sums over multiple point light sources =-=[17][2-=-7][36], are impractical for real-time rendering. Real-time, realistic global illumination encounters three difficulties – it must model the complex, spatially-varying BRDFs of real materials (BRDF c... |

139 |
A global illumination solution for general reflectance distributions
- Sillion, Arvo, et al.
- 1991
(Show Context)
Citation Context ... is static and the receiver’s effect on itself and its environment is ignored.sSpherical harmonics have been used to represent incident radiance and BRDFs for offline rendering and BRDF inference [4=-=] [38]-=-[42]. Westin, et al. [42] use a matrix representation for 4D BRDF functions in terms of the SH basis identical to our transfer matrix. But rather than the BRDF, we use it to represent global and spati... |

114 | Interactive rendering with arbitrary brdfs using separable approximations - Kautz, McCool - 1999 |

109 | Fast calculation of soft shadow textures using convolution
- SOLER, SILLION
- 1998
(Show Context)
Citation Context ...ht sources has been handled by multi-pass rendering that sums over a light source decomposition into points or small sources [17][27][36]. Large light sources become very expensive. Another technique =-=[39]-=- uses FFT convolution of occluder projections for soft shadowing with cost independent of light source size. Only shadows between pre-segmented clusters of objects are handled, making self-shadows on ... |

80 | The irradiance volume
- GREGER, SHIRLEY, et al.
- 1998
(Show Context)
Citation Context ...ons and refractions. We apply a similar precomputed, perobject decomposition but designed instead for soft shadows and caustics on nearly diffuse objects in low-frequency lighting. Irradiance volumes =-=[15] a-=-llow movement of diffuse receivers in precomputed lighting. Unlike our approach, lighting is static and the receiver’s effect on itself and its environment is ignored.sSpherical harmonics have been ... |

72 | Efficient image-based methods for rendering soft shadows
- Agrawala, Ramamoorthi, et al.
- 2000
(Show Context)
Citation Context ...e basic technique, some suitable for real-time rendering, have since been described: percentage-closer filtering [35], which softens shadow edges, layered depth maps [26] and layered attenuation maps =-=[1]-=-, which more accurately simulate penumbra shape and falloff, and deep shadow maps [29], which generalize the technique to partially transparent and volume geometry. All these techniques assume point o... |

64 |
Efficient Algorithms for Local and Global Accessibility Shading
- MILLER
- 1994
(Show Context)
Citation Context ...adowing with cost independent of light source size. Only shadows between pre-segmented clusters of objects are handled, making self-shadows on complex meshes difficult. Finally, accessibility shading =-=[32]-=- is also based on precomputed global visibility, but is a scalar quantity that ignores changes in lighting direction. Methods for nonlocal lighting on micro-geometry include the horizon map [4][31], w... |

24 | A quick rendering method using basis functions for interactive lighting design,” Eurographics: 229–240
- Dobashi, Kaneda, et al.
- 1995
(Show Context)
Citation Context ...component analysis to reduce the basis set. Our work differs by computing a transfer field over the object’s surface in 3D rather than over a fixed 2D view to allow viewpoint changes. Dobashi, et al=-=. [10]-=- use the SH basis and transfer vector fields over surfaces to allow viewpoint change but restrict lighting changes to the directional intensity distribution of an existing set of non-area light source... |

21 |
An Efficient Representation for Irradiance Environment
- Ramamoorthi, Hanrahan
- 2001
(Show Context)
Citation Context ...nalytic or tabulated BRDF at a few points, but becomes intractable for large light sources. A second line of research samples radiance and preconvolves it with kernels of various sizes [5][14][19][24]=-=[34]-=-. This solves the light integration problem but ignores light transport complexities like shadows since the convolution assumes the incident radiance is unoccluded and unscattered. Finally, clever tec... |

21 |
Angular Momentum: Understanding Spatial Aspects in Chemistry and
- Zare
- 1988
(Show Context)
Citation Context ...ex) represent low-frequency basis functions over the sphere. The basis functions for band l reduce to polynomials of order l in x, y, and z. Evaluation can be done with simple recurrence formulas [13]=-=[44].-=- Projection and Reconstruction Because the SH basis is orthonormal, a scalar function f defined over S can be projected into its coefficients via the integral m m fl = Ú f() s yl () s ds (1) These co... |

18 | Efficient linear re-rendering for interactive lighting design,” Stanford Univ
- Teo, Simoncelli, et al.
- 1997
(Show Context)
Citation Context ...tially the spherical monomials, is related to the SH by a linear transformation and thus shares some of its properties (e.g., rotational invariance) but not others (e.g., orthonormality). Teo, et al. =-=[40] g-=-eneralize to non-infinite sources, using principal component analysis to reduce the basis set. Our work differs by computing a transfer field over the object’s surface in 3D rather than over a fixed... |

16 | Steerable illumination textures
- Ashikhmin, Shirley
(Show Context)
Citation Context ...a higher-dimensional texture, polynomial texture maps [30] allow real-time interreflection effects as well as shadowing. A similar approach using a steerable basis for directional lighting is used in =-=[3]-=-. Like our approach, these methods precompute a simple representation of a transfer function, but one based on directional light sources and thus requiring costly multipass integration to simulate are... |

14 | Realistic Reflections and Refractions on Graphics Hardware with Hybrid Rendering and Layered Environment Maps
- Hakura, Snyder
- 2001
(Show Context)
Citation Context ...to real-time rendering, but cache a transfer function parameterized by a SH lighting basis rather than scalar irradiance. Precomputed transfer using light-field remapping [18] and dynamic ray tracing =-=[16]-=- has been used to achieve highly specular reflections and refractions. We apply a similar precomputed, perobject decomposition but designed instead for soft shadows and caustics on nearly diffuse obje... |

8 |
Horizon Mapping: shadows for bump-mapped surfaces”, The Visual Computer
- Max
- 1988
(Show Context)
Citation Context ...ng [32] is also based on precomputed global visibility, but is a scalar quantity that ignores changes in lighting direction. Methods for nonlocal lighting on micro-geometry include the horizon map [4]=-=[31]-=-, which efficiently renders self-shadowing from point lights. In [20], this technique is tailored to graphics hardware and generalized to diffuse interreflections, though diffuse surface self-transfer... |

7 |
Shading Ambiguity: Reflectance and Illumination
- D’Zmura
- 1991
(Show Context)
Citation Context ...er matrix. But rather than the BRDF, we use it to represent global and spatially varying transport effects like shadows. The SH basis has also been used to solve ambiguity problems in computer vision =-=[12]-=- and to represent irradiance for rendering [34]. 3. Review of Spherical Harmonics Definition Spherical harmonics define an orthonormal basis over the sphere, S, analogous to the Fourier transform over... |

3 |
Global Illumination using
- Jensen
- 1996
(Show Context)
Citation Context ...nd interreflections are important effects in realistic image synthesis. Unfortunately, general methods for integrating over large-scale lighting environments [8], including Monte Carlo ray tracing [7]=-=[21]-=-[25], radiosity [6], or multi-pass rendering that sums over multiple point light sources [17][27][36], are impractical for real-time rendering. Real-time, realistic global illumination encounters thre... |

3 |
A Unified Approach to Prefiltered Environment
- KAUTZ, VAZQUEZ, et al.
- 2000
(Show Context)
Citation Context ...an analytic or tabulated BRDF at a few points, but becomes intractable for large light sources. A second line of research samples radiance and preconvolves it with kernels of various sizes [5][14][19]=-=[24]-=-[34]. This solves the light integration problem but ignores light transport complexities like shadows since the convolution assumes the incident radiance is unoccluded and unscattered. Finally, clever... |

3 |
Penumbras for Complex Objects by DepthDependent Filtering
- KEATING, MAX, et al.
- 1996
(Show Context)
Citation Context ...rce shadows. Many extensions of the basic technique, some suitable for real-time rendering, have since been described: percentage-closer filtering [35], which softens shadow edges, layered depth maps =-=[26]-=- and layered attenuation maps [1], which more accurately simulate penumbra shape and falloff, and deep shadow maps [29], which generalize the technique to partially transparent and volume geometry. Al... |

2 |
Spherical Wavelets: Efficiently Representing the Sphere,” Siggraph ’95
- Schröder, Sweldens
- 1995
(Show Context)
Citation Context ...nsfer [34]. Because of its rotational invariance (equation (4)), we consider the SH basis especially useful for our low-frequency lighting application compared to alternatives like spherical wavelets =-=[37]. Wh-=-en dynamically sampling incident radiance, this property eliminates aliasing which would otherwise produce temporal artifacts, like shading “wobble”, if projected to other bases with the same numb... |

1 |
Efficient Re-rendering of Natural Environments, Eurographics Workshop on Rendering
- NIMEROFF, SIMONCELLI, et al.
- 1994
(Show Context)
Citation Context ... over its surface. Meanwhile, incident radiance need not be precomputed. The graphics hardware can dynamically sample incident radiance at a number of points. Analytic models, such as skylight models =-=[33]-=- or simple geometries like circles, can also be used. By representing both incident radiance and transfer functions in a linear basis (in our case, SH), we exploit the linearity of light transport to ... |