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370
Efficient Binary Space Partitions for HiddenSurface Removal and Solid Modeling
, 1990
"... We consider schemes for recursively dividing a set of geometric objects by hyperplanes until all objects are separated. Such a binary space partition, or BSP, is naturally considered as a binary tree where each internal node corresponds to a division. The goal is to choose the hyperplanes properly ..."
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Cited by 103 (0 self)
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We consider schemes for recursively dividing a set of geometric objects by hyperplanes until all objects are separated. Such a binary space partition, or BSP, is naturally considered as a binary tree where each internal node corresponds to a division. The goal is to choose the hyperplanes properly so that the size of the BSP, i.e., the number of resulting fragments of the objects, is minimized. For the twodimensional case, we construct BSPs of size O(n log n) for n edges, while in three dimensions, we obtain BSPs of size O(n²) for n planar facets and prove a matching lower bound of Ω(n²). Two applications of efficient BSPs are given. The first is an O(n²)sized data structure for implementing a hiddensurface removal scheme of Fuchs et al. [6]. The second application is in solid modeling: given a polyhedron described by its n faces, we show how to generate an O(n²)sized CSG (constructivesolidgeometry) formula whose literals correspond to halfspaces supporting the faces of the polyhedron. The best previous results for both of these problems were O(n³).
ImageDriven Simplification
, 2000
"... We introduce the notion of imagedriven simplification, a framework that uses images to decide which portions of a model to simplify. This is a departure from approaches that make polygonal simplification decisions based on geometry. As with many methods, we use the edge collapse operator to make ..."
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Cited by 100 (5 self)
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We introduce the notion of imagedriven simplification, a framework that uses images to decide which portions of a model to simplify. This is a departure from approaches that make polygonal simplification decisions based on geometry. As with many methods, we use the edge collapse operator to make incremental changes to a model. Unique to our approach, however, is the use of comparisons between images of the original model against those of a simplified model to determine the cost of an edge collapse. We use common graphics rendering hardware to accelerate the creation of the required images. As expected, this method produces models that are close to the original model according to image differences. Perhaps more surprising, however, is that the method yields models that have high geometric fidelity as well. Our approach also solves the quandary of how to weight the geometric distance versus appearance properties such as normals, color and texture. All of these tradeoffs are ba...
Incremental algorithms for collision detection between solid models
 IEEE Transactions on Visualization and Computer Graphics
, 1995
"... solid models ..."
Near realtime shadow generation using bsp trees
 Computer Graphics
, 1989
"... This paper describes an objectspace shadow generation algorithm for static polygonal environments illuminated by movable point light sources. The algorithm can be easily implemented on any graphics system that provides fast polygon scanconversion and achieves near realtime performance for environ ..."
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Cited by 88 (0 self)
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This paper describes an objectspace shadow generation algorithm for static polygonal environments illuminated by movable point light sources. The algorithm can be easily implemented on any graphics system that provides fast polygon scanconversion and achieves near realtime performance for environments of modest size. It combines elements of two kinds of current shadow generation algorithms: twopass objectspace approaches and shadow volume approaches. For each light source a Binary Space Partitioning (BSP) tree is constructed that represents the shadow volume of the polygons facing it. As each polygon's contribution to a light source's shadow volume is determined, the polygon's shadowed and lit fragments are computed by filtering it down the shadow volume BSP tree. The polygonal scene with its computed shadows can be rendered with any polygonbased visiblesurface algorithm. Since the shadow volumes and shadows are computed in object space, they can be used for further analysis of the scene. Pseudocode is provided, along with pictures and timings from an interactive implementation.
Provisioning Online Games: A Traffic Analysis of a Busy CounterStrike Server
 in Internet Measurement Workshop
, 2002
"... This paper describes the results of a 500 million packet trace of a popular online, multiplayer, game server. The results show that the traffic behavior of this heavily loaded game server is highly predictable and can be attributed to the fact that current game designs target the saturation of the ..."
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Cited by 88 (12 self)
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This paper describes the results of a 500 million packet trace of a popular online, multiplayer, game server. The results show that the traffic behavior of this heavily loaded game server is highly predictable and can be attributed to the fact that current game designs target the saturation of the narrowest, lastmile link. Specifically, in order to maximize the interactivity of the game and to provide relatively uniform experiences between all players, online games typically fix their usage requirements in such a way as to saturate the network link of their lowest speed players. While the traffic observed is highly predictable, the trace also indicates that these online games provide significant challenges to current network infrastructure. Due to synchronous game logic requiring an extreme amount of interactivity, a close look at the trace reveals the presence of large, highly periodic, bursts of small packets. With such stringent demands on interactivity, routers must be designed with enough capacity to quickly route such bursts without delay. As current routers are designed for bulk data transfers with larger packets, a significant, concentrated deployment of online game servers will have the potential for overwhelming current networking equipment.
Rendering Parametric Surfaces in Pen and Ink
, 1996
"... This paper presents new algorithms and techniques for rendering parametric freeform surfaces in pen and ink. In particular, we introduce the idea of “controlleddensity hatching ” for conveying tone, texture, and shape. The fine control over tone this method provides allows the use of traditional t ..."
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Cited by 81 (3 self)
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This paper presents new algorithms and techniques for rendering parametric freeform surfaces in pen and ink. In particular, we introduce the idea of “controlleddensity hatching ” for conveying tone, texture, and shape. The fine control over tone this method provides allows the use of traditional texture mapping techniques for specifying the tone of penandink illustrations. We also show how a planar map, a data structure central to our rendering algorithm, can be constructed from parametric surfaces, and used for clipping strokes and generating outlines. Finally, we show how curved shadows can be cast onto curved objects for this style of illustration.
A traffic characterization of popular online games
 IEEE/ACM Transactions on Networking
, 2005
"... Abstract—This paper describes the results of the first comprehensive analysis of a range of popular online, multiplayer, game servers. The results show that the traffic behavior of these servers is highly predictable and can be attributed to the fact that current game designs target the saturation ..."
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Cited by 73 (1 self)
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Abstract—This paper describes the results of the first comprehensive analysis of a range of popular online, multiplayer, game servers. The results show that the traffic behavior of these servers is highly predictable and can be attributed to the fact that current game designs target the saturation of the narrowest, lastmile link. Specifically, in order to maximize the interactivity of the game itself and to provide relatively uniform experiences between players playing over different network speeds, online games typically fix their usage requirements in such a way as to saturate the network link of their lowest speed players. While the traffic observed is highly predictable, the traces also indicate that these online games provide significant challenges to current network infrastructure. As a result of synchronous game logic requiring an extreme amount of interactivity, a close look at the trace reveals the presence of large, highly periodic, bursts of small packets. With such stringent demands on interactivity, routers must be designed with enough capacity to quickly route such bursts without delay. Index Terms—Communication system traffic, games, measurement, network servers, networks.
Computing the Antipenumbra of an Area Light Source
 Computer Graphics
, 1992
"... We define the antiumbra and the antipenumbra of aconvex area light source shining through a sequence of convex areal holes in three dimensions. The antiumbra is the volume from which all points on the light source can be seen. The antipenumbra is the volume from which some, but not all, of the light ..."
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Cited by 67 (0 self)
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We define the antiumbra and the antipenumbra of aconvex area light source shining through a sequence of convex areal holes in three dimensions. The antiumbra is the volume from which all points on the light source can be seen. The antipenumbra is the volume from which some, but not all, of the light source can be seen. We show that the antipenumbra is, in general, a disconnected set bounded by portions of quadric surfaces, and describe an implemented O(n 2 ) time algorithm that computes this boundary, where n is the total number of edges comprising the light source and holes. The antipenumbra computation is motivated by a visibility scheme in which we wish to determine the volume visible to an observer looking through a sequenceof transparent convex holes, or portals, connecting adjacent cells in a spatial subdivision. Knowledge of the antipenumbra should also prove useful for rendering shadowed objects. Finally, we have extended the algorithm to compute the planar and quadratic su...
Clustering for Glossy Global Illumination
 ACM TRANSACTIONS ON GRAPHICS
, 1997
"... We present a new clustering algorithm for global illumination in complex environments. The new algorithm extends previous work on clustering for radiosity to allow for nondiffuse (glossy) reflectors. We represent clusters as points with directional distributions of outgoing and incoming radiance and ..."
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Cited by 65 (4 self)
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We present a new clustering algorithm for global illumination in complex environments. The new algorithm extends previous work on clustering for radiosity to allow for nondiffuse (glossy) reflectors. We represent clusters as points with directional distributions of outgoing and incoming radiance and importance, and we derive an error bound for transfers between these clusters. The algorithm groups input surfaces into a hierarchy of clusters, and then permits clusters to interact only if the error bound is below an acceptable tolerance. We show that the algorithm is asymptotically more efficient than previous clustering algorithms even when restricted to ideally diffuse environments. Finally, we demonstrate the performance of our method on two complex glossy environments.