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Fast object-precision shadow generation for area light source

Norman Chin, Steven Feiner
1992 Proceedings of the 1992 symposium on Interactive 3D graphics - SI3D '92  
This paper introduces an efficient object-precision shadow generation algorithm for static polygonal environments directly illuminated by convex area light sources.  ...  We use a fast analytic algorithm to compute the fragments of the area light source visible from a point in penumbra.  ...  Furthermore, these volumes are represented as BSP trees [14, 15, 21, 161 using an efficient extension of the earlier BSP-tree-based shadow algorithm for point light sources [7] .  ... 
doi:10.1145/147156.147159 dblp:conf/si3d/ChinF92 fatcat:w6n47du5rzagnaewxocnlhzhre

Lazy Visibility Evaluation for Exact Soft Shadows

F. Mora, L. Aveneau, O. Apostu, D. Ghazanfarpour
2012 Computer graphics forum (Print)  
We apply this algorithm to solve exactly and efficiently the visibility of an area light source from any point in a scene.  ...  As a consequence, results are not sensitive to noise, contrary to soft shadows methods based on area light source sampling.  ...  Ray-traced soft shadows are computed using groups of 4 shadow rays, and an uncorrelated stratified sampling of the area light sources.  ... 
doi:10.1111/j.1467-8659.2011.02089.x fatcat:4xmfxppfvrfsfeeykufqvm47hi

Near real-time shadow generation using BSP trees

Norman Chin, Steven Feiner
1989 Computer graphics  
For each light source a Binary Space Partitioning (BSP) tree is constructed that represents the shadow volume of the polygons facing it.  ...  This paper describes an object-space shadow generation algorithm for static polygonal environments illuminated by movable point light sources.  ...  Program, and the New York State Center for Advanced Technology under Contract NYSSTF-CAT(88)-5.  ... 
doi:10.1145/74334.74343 fatcat:6hkqh3qsibag3ab2nvee74oqay

Near real-time shadow generation using BSP trees

Norman Chin, Steven Feiner
1989 Proceedings of the 16th annual conference on Computer graphics and interactive techniques - SIGGRAPH '89  
For each light source a Binary Space Partitioning (BSP) tree is constructed that represents the shadow volume of the polygons facing it.  ...  This paper describes an object-space shadow generation algorithm for static polygonal environments illuminated by movable point light sources.  ...  Program, and the New York State Center for Advanced Technology under Contract NYSSTF-CAT(88)-5.  ... 
doi:10.1145/74333.74343 dblp:conf/siggraph/ChinF89 fatcat:vo2irchsdvbqbd6boldsmf2qde

A comparison of three shadow volume algorithms

Mel Slater
1992 The Visual Computer  
Binary Space Partition trees are used to organise the polygons in the scene in a frontto-back order from the point of view of the light source, and then shadows on a polygon are computed by clipping the  ...  polygon to the shadow volumes of polygons closer to the light source.  ...  The author is indebted to the referees for their insights and suggestions. Thanks to T. Lin for commenting on an earlier draft.  ... 
doi:10.1007/bf01901026 fatcat:3t4gzklkhrcw3jrvogqrg436ju

An Improved Physically-Based Soft Shadow Volume Algorithm

Jaakko Lehtinen, Samuli Laine, Timo Aila
2006 Computer graphics forum (Print)  
We identify and analyze several performance problems in a state-of-the-art physically-based soft shadow volume algorithm, and present an improved method that alleviates these problems by replacing an overly  ...  These include the unintrusiveness of the original algorithm, meaning that our method can be used as a black-box shadow solver in any offline renderer without requiring multiple passes over the image or  ...  Stochastic ray tracing Stochastic ray tracing algorithms compute shadows by sampling an area light source using shadow rays [CPC84] .  ... 
doi:10.1111/j.1467-8659.2006.00949.x fatcat:7abacwkh6vec7hd46ipxlae5rm

Partitioned Shadow Volumes

J. Gerhards, F. Mora, L. Aveneau, D. Ghazanfarpour
2015 Computer graphics forum (Print)  
Our algorithm uses a new partitioning strategy which avoids any polygon clipping. It relies on a Ternary Object Partitioning tree, a new data structure used to find if an image point is shadowed.  ...  This paper rediscovers an old class of algorithms that build a binary space partition over the shadow volumes.  ...  The authors especially thank Erik Sintorn for providing the models and data used in [SKOA14]. The Epic Citadel scene is distributed with the Unreal Development Kit by Epic Games.  ... 
doi:10.1111/cgf.12583 fatcat:durpoojdf5d5zfhqyelafgeuhi

Out of core Polyhedral Union and its Application to Interactive Shadow Rendering [article]

J. Fedorkiw, C. Smith, S. Ghali
2006 Computer Graphics and Visual Computing  
We show that the algorithm is practical by providing time and space statistics. We also show the benefit of using the resulting union solid for computing interactive shadows.  ...  We describe a time and spaceefficient BSP-based algorithm for computing the union of a set of solids and compare it with the other solid representations.  ...  By using the concise shadow volumes to produce shadows for a scene we minimize the surface area of the shadow volumes that need to be rendered.  ... 
doi:10.2312/localchapterevents/tpcg/tpcg06/141-148 dblp:conf/tpcg/FedorkiwSG06 fatcat:zw2mroa23rgizcuhsswnznkimi

Alias-Free Shadow Maps [article]

Timo Aila, Samuli Laine
2004 Symposium on Rendering  
In this paper we abandon the regular structure of shadow maps. Instead, we transform the visible pixels P(x, y, z) from screen space to the image plane of a light source P0(x0, y0, z0).  ...  This eliminates the resolution issues that have plagued shadow maps for decades, e.g., jagged shadow boundaries.  ...  Acknowledgements We would like to thank Jukka Arvo, Jaakko Lehtinen, Ville Miettinen and Lauri Savioja for their helpful comments.  ... 
doi:10.2312/egwr/egsr04/161-166 fatcat:ihvdiji3znbbnla4dtfy7aphn4

A Visibility Field for Ray Tracing

Jesper Mortensen, Pankaj Khanna, Insu Yu, Mel Slater
2007 Computer Graphics, Imaging and Visualisation (CGIV 2007)  
Objects lying along a beam are sorted using a 1D BSP along the beam direction.  ...  The beam corresponding to any ray can be looked up in small constant time and the set of objects corresponding to the beam can then be searched for intersection with the ray using an optimised traversal  ...  Thanks to Ingo Wald and Carsten Benthin for helpful suggestions on real time ray tracing.  ... 
doi:10.1109/cgiv.2007.14 dblp:conf/IEEEcgiv/MortensenKYS07 fatcat:qds6oplkg5avjgpu4grmeqkncy

Scalable Real-Time Shadows using Clustering and Metric Trees

François Deves, Frédéric Mora, Lilian Aveneau, Djamchid Ghazanfarpour
2018 Eurographics Symposium on Rendering  
Then, this tree is used as an acceleration data structure to determine the visibility of the light for each image point.  ...  Real-time shadow algorithms based on geometry generally produce high quality shadows. Recent works have considerably improved their efficiency.  ...  A BSP tree is built over the shadow volumes using polyhedral set operations to partition space into lighted and occluded regions.  ... 
doi:10.2312/sre.20181175 dblp:conf/rt/DevesMAG18 fatcat:7gnjykyvp5cr3coejncxejepta

Discontinuity meshing for accurate radiosity

D. Lischinski, F. Tampieri, D.P. Greenberg
1992 IEEE Computer Graphics and Applications  
We discuss the problem of accurately computing the illumination of a diffuse polyhedral environment due to an area light source.  ...  The shape, location, and order of these discontinuities is determined by the geometry of the light sources and obstacles in the environment.  ...  Matt Hyatt modeled the Victorian room environment used in the simulation.  ... 
doi:10.1109/38.163622 fatcat:na3mxsc2hvbkxiqhztizgiuhfi

Hierarchical Penumbra Casting

Samuli Laine, Timo Aila
2005 Computer graphics forum (Print)  
Instead of casting shadow rays, we place both the points to be shaded and the samples of an area light source into separate hierarchies, and compute hierarchically the shadows caused by each occluding  ...  We present a novel algorithm for rendering physically-based soft shadows in complex scenes.  ...  Acknowledgements We thank Jaakko Lehtinen, Janne Kontkanen and Lauri Savioja for fruitful discussions. The original Sponza Atrium model by Marko Dabrovic, RNA studio, www.rna.hr.  ... 
doi:10.1111/j.1467-8659.2005.00856.x fatcat:4gpusmoqq5eatizygojgqfmoc4

Visibility in Computer Graphics

Jiří Bittner, Peter Wonka
2003 Environment and Planning, B: Planning and Design  
The paper surveys visible surface algorithms, visibility culling algorithms, visibility algorithms for shadow computation, global illumination, point-based and image-based rendering, and global visibility  ...  Nowadays there are many different visibility algorithms for various visibility problems.  ...  Shadow volumes An adaptation of the SVBSP tree for areal light sources was proposed by Chin and Feiner (1992) .  ... 
doi:10.1068/b2957 fatcat:oh7rtfzoxfgtppd7njq37ef6ci

Efficient Sorting and Searching in Rendering Algorithms [article]

Vlastimil Havran, Jiri Bittner
2006 Eurographics State of the Art Reports  
In the proposed tutorial we would like to highlight the connection between rendering algorithms and sorting and searching as classical problems studied in computer science.  ...  In particular we will discuss problems and solutions for visibility computation, density estimation, and importance sampling.  ...  Acknowledgements We would like to thank Robert Herzog, Jaroslav Křivánek, Michael Wimmer, Peter Wonka, Tommer Leyvand, David Luebke, and Hansong Zhang for providing us various materials used in the tutorial  ... 
doi:10.2312/egt.20061061 fatcat:nhf62nzo2jczbhksy3h7oywrs4
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