waashk/acm huggingface dataset:
interactive display of large-scale nurbs models  we present serial and parallel algorithms for interactive rendering of large scale and complex nurbs models on current graphics systems. the algorithms tessellate the nurbs surfaces into triangles and render them using triangle rendering engines. the main characteristics of the algorithms are improved polygonization algorithms, exploitation of spatial and temporal coherence and back-patch culling. polygonization anomalies like cracks and angularities are avoided. we analyze a number of issues in parallelization of these techniques, as well. the algorithms work well in practice and are able to display models consisting of thousands of surfaces at interactive frame rates on the highly parallel graphics system, pixel-planes 5.  subodh kumar dinesh manocha anselmo lastra
multi-resolution multi-field ray tracing: a mathematical overview  a rigorous mathematical review of ray tracing is presented. the concept of a generic voxel decoder acting on flexible voxel formats is introduced. the necessity of interpolating opacity weighted colors is proved, using a new definition of the blending process in terms of functional integrals. the continuum limit of the discrete opacity accumulation formula is presented, and its convexity properties are investigated. the issues pertaining to interpolation/classification order are discussed. the lighting equation is expressed in terms of opacity weighted colors. the multi-resolution (along the ray) correction of the opacity-weighted color is derived. the mathematics of filtering on the image plane are studied, and an upper limit of the local pixel size on the image plane is obtained. interpolation of pixel values on the image plane is shown to be inequivalent to blending of interpolated samples.  c. gasparakis
the versatility of color mapping  extracting information from large amounts of data by using tables of numbers is difficult. often, such data can be presented more effectively with graphics. the reduction in the cost of memory has allowed more powerful display systems to provide for the simultaneous display of hundreds, thousands, and even millions of colors. effective and efficient manipulation of the colors in the display system is necessary to manage the use of such a large number of colors. these extended color capabilities can also be used to enrich the understanding of presentations of complex data sets. applications which previously might have required the user to mentally correlate several displays can now display the same information in a single image with a corresponding increase in user understanding and accuracy of interpretation.  samuel p. uselton mark e. lee randy a. brown
on the partitionability of hierarchical radiosity  the hierarchical radiosity algorithm (hra) is one of the most efficient sequential algorithms for physically based rendering. unfortunately, it is hard to implement in parallel. there exist fairly efficient shared-memory implementations but things get worst in a distributed memory (dm) environment. in this paper we examine the structure of the iira in a graph partitioning setting. various measurements performed on the task access graph of the hra indicate the existance of several bottlenecks in a potential dm implementation. we compare "optimal" partitioning results obtained by the partitioning software metis with a trivial and a spatial partitioning algorithm, and show that the spatial partitioning copes with most of the bottlenecks well.  robert garmann
towards interactive bump mapping with anisotropic shift-variant brdfs  in this paper a technique is presented that combines interactive hardware accelerated bump mapping with shift-variant anisotropic reflectance models. an evolutionary path is shown how some simpler reflectance models can be rendered at interactive rates on current low-end graphics hardware, and how features from future graphics hardware can be exploited for more complex models.  we show how our method can be applied to some well known reflectance models, namely the banks model, ward's model, and an anisotropic version of the blinn- phong model, but it is not limited to these models.  furthermore, we take a close look at the necessary capabilities of the graphics hardware, identifiy problems with current hardware, and discuss possible enhancements.  jan kautz hans-peter seidel
the detailed semantics of graphics input devices  the concept of virtual input devices, enunciated by wallace, has been the accepted basis for producing device-independent interactive graphics systems. it was used by gspc for the core system, and it underlies the draft international standard gks.  during the recently concluded technical review of gks, the input facilities became a bone of contention. the discussions revealed many inadequacies in the virtual input device concept, and were finally resolved using a refined and extended model of input, which is presented here by some of the participants in the discussions. examples are included, showing how the gks facilities derive from the model, and the core's "stroke" device is used to show how the model controls future extensions to gks. the model is also used to describe the other differences between the input facilities of the core system and gks.  david s. h. rosenthal james c. michener gunther pfaff rens kessener malcolm sabin
a device-independent network graphics system  the design and implementation of a basic graphics system for a heterogeneous network environment is described. the design has been influenced by the siggraph core system, gks, and proposals being considered by the ansi technical committee on computer graphics programming languages. it permits hierarchical object definition, direct and indirect attribute specification, screen window management and complex styles of interaction. important parts of the implementation include a device-independent database for graphical objects, a workstation driver which produces device code, and a device kernel which manages the display list. problems relating to device independence and network partitioning are discussed.  deborah u. cahn albert c. yen
a retrospective (panel): six perennial issues in computer graphics  graphics has been an industry for more than 15 years. some workers trace its origins almost )0 years. the dramatic gains in silicon technology along with more highly developed understanding of the mathematics of graphics have transformed the architecture of computer graphic systems and produced a bewildering array of products and services.  this retrospective panel will try to put several key things in perspective. dr. alan kay, recently of atari computer and currently an apple fellow, will characterize the role of graphics in the overall world of computing and information processing. carl machover of machover associates will trace the development of display technology and its employment in computer graphics systems. dr. david evan, chairman of the board of evans and sutherland will create the retrospective on our ability to produce realism in imagery. in turn dr. robert sproull, sutherland, sutherland and associates will trace the development of transformation that have found their way into silicon technology. dr. james foley, of george washington university will track our progress in the technology of interaction, while dr. robin forrest of the university of east angela will trace geometric modeling and dr. ed cattail, director of development at lucasfilm will put our progress in animation in perspective.  robert m. dunn
minimum cost adaptive synchronization: experiments with the parasol system  we present a novel adaptive synchronization algorithm, called the minimum average cost (mac) algorithm, in the context of the parasol parallel simulation system. parasol is a multithreaded system for parallel simulation on shared- and distributed-memory environments, designed to support domain- specific simulation object libraries. the proposed mac algorithm is based on minimizing the cost of synchronization delay and rollback at a process, whenever its simulation driver must decide whether to either proceed optimistically or to delay processing. in the former case the risk is rollback cost, in the event of a straggler's arrival. in the latter case the risk is unnecessary delay, in the event a latecomer is not a straggler. in addition to the mac algorithm and an optimal delay computation model, we report on some early experiments comparing the performance of mac-based adaptive synchronization to optimistic synchronization.  edward mascarenhas felipe knop reuben pasquini vernon rego
an inexpensive scheme for calibration of a colour monitor in terms of cie standard coordinates  the commission internationale d'eclairage system of colorimetry is a method of measuring colours that has been standardized, and is widely used by industries involved with colour. knowing the cie coordinates of a colour allows it to be reproduced easily and exactly in many different media. for this reason graphics installations which utilize colour extensively ought to have the capability of knowing the cie coordinates of displayed colours, and of displaying colours of given cie coordinates. such a capability requires a function which transforms video monitor gun voltages (rgb colour space) into cie coordinates (xyz colour space), and vice versa. the function incorporates certain monitor parameters. the purpose of this paper is to demonstrate the form that such a function takes, and to show how the necessary monitor parameters can be measured using little more than a simple light meter. because space is limited, and because each user is likely to implement the calibration differently, few technical details are given, but principles and methods are discussed in sufficient depth to allow the full use of the system. in addition, several visual checks which can be used for quick verification of the integrity of the calibration are described.  the paper begins with an overview of the cie system of colorimetry. it continues with a general discussion of transformations from rgb colour space to xyz colour space, after which a detailed step-by-step procedure for monitor calibration is presented.  william b. cowan
shading of regions on vector display devises  given an arbitrary simple polygon with n vertices we present an algorithm for shading the interior of the polygon with a set of parallel lines where the slope and the distance between lines are prespecified. if the number of shading line segments is m, the algorithm described in the paper runs in 0(n log n + m) time. the algorithm is generalizable to shade any region or regions of an arbitrary planar subdivision.  d. t. lee
a simple naturalistic hair model we propose a new computer graphics model to render naturalistic human hair. in this model, a simplified progressive polyline simulation was used for fast processing. the problems of inter-hair collisions and hair-head collisions were avoided by certain assumptions, and the bend in the hair was provided by angle-dependent pseudo-force equations. several hair-colour and shadowing techniques were tested. despite the simplicity of the hair model itself, when it was combined with the coloring and shadowing techniques described here, the proposed model did effectively render hair, as illustrated by the still images. john rankin richard hall
a unified representation for numerical and qualitative simulations models fall naturally into two main categories, those of discrete systems and those of continuous systems. our model-based reasoning work deals with continuous systems, augmented to provide for the possibility that one continuous system model transitions to another, as when a threshold event occurs such as a thermostat turning on.one aspect of model-based reasoning is simulation. a model is defined and its behavior(s) inferred through qualitative or numerical simulation. the simulated trajectories then facilitate tasks that one expects model-based reasoning to aid in, such as prediction, monitoring, diagnosis, and design.here we describe an approach to representing simulation trajectories that results in descriptions of system behavior that contain both qualitative and quantitative information about trajectories closely integrated together. those descriptions are supported by an internal, representation methodology that also closely integrates qualitative and quantitative information. the internal representation methodology supports quantitative inferences about the trajectories, and an example trace of such inferencing is provided. daniel berleant
matchmaking among minimal agents without a facilitator  multi-agent systems are a promising way of dealing with large complex problems. however, it is not yet clear just how much complexity or pre- existing structure individual agents must have to allow them to work together effectively. in this paper, we ask to what extent agents with minimal resources, local communication and without a directory service can solve a consumer-provider matchmaking problem. we are interested in finding a solution that is massively scalable and can be used with resource poor agents in an open system. we create a model involving random search and a grouping procedure. through simulation of this model, we show that peer-to-peer communication in a environment with multiple copies of randomly distributed like clients and providers is sufficient for most agents to discover the service consumers or providers they need to complete tasks. we simulate systems with between 500 and 32,000 agents, between 10 and 2000 categories of services, and with three to six services required by each agent. we show that, for instance, in a system with 80 service categories and 2000 agents, each requiring three random services between 93\% and 97\% of possible matches are discovered. such a system can work with at least 90 different service categories and tens of thousands of agents.  elth ogston stamatis vassiliadis
image-based motion blur for stop motion animation  stop motion animation is a well-established technique where still pictures of static scenes are taken and then played at film speeds to show motion. a major limitation of this method appears when fast motions are desired; most motion appears to have sharp edges and there is no visible motion blur. appearance of motion blur is a strong perceptual cue, which is automatically present in live-action films, and synthetically generated in animated sequences. in this paper, we present an approach for automatically simulating motion blur. ours is wholly a post-process, and uses image sequences, both stop motion or raw video, as input. first we track the frame-to-frame motion of the objects within the image plane. we then integrate the scene's appearance as it changed over a period of time. this period of time corresponds to shutter speed in live-action filming, and gives us interactive control over the extent of the induced blur. we demonstrate a simple implementation of our approach as it applies to footage of different motions and to scenes of varying complexity. our photorealistic renderings of these input sequences approximate the effect of capturing moving objects on film that is exposed for finite periods of time.  gabriel j. brostow irfan essa
design and implementation of an immersive geoscience toolkit (case study)  having a better way to represent and to interact with large geological models are topics of high interest in geoscience, and especially for oil and gas companies. we present in this paper the design and implementation of a visualization program that involves two main features. it is based on the central data model, in order to display in real time the modifications caused by the modeler. furthermore, it benefits from the different immersive environments which give the user a much more accurate insight of the model than a regular computer screen. then, we focus on the difficulties that come in the way of performance.  christophe winkler fabien bosquet xavier cavin jean-claude paul
a simple method for improved color printing of monitor images  to print image data optimized for display on a color monitor, the red, green, and blue values that drive the display must be transformed into data that control the amounts of cyan, magenta, yellow, and black on the print. the differences in the way display and print images are produced have important consequences for the transformation. matching the appearance of the monitor and print images may be impossible, and achieving satisfactory results is complex. a method for obtaining pleasing prints from display image data is presented. this method assumes that good results can be achieved by users who do not have extensive knowledge of color reproduction and who have a minimum of color measuring equipment available.  michael g. lamming warren l. rhodes
can legal knowledge be derived from legal texts?  knowledge acquisition is undoubtedly one of the major bottle-necks in the development of legal expert systems. usually the knowledge is collected by knowledge engineers who are forced to make their own interpretations of the knowledge in order to map it on a knowledge representation technique, thus resulting into erroneous and legally unacceptable interpretations of the law. the aim of nomos (an ec supported project under the esprit ii initiative) was to assist the knowledge engineer by providng tools that perform semi-automatic knowledge acquisition from legal texts in italian and french. this paper reports on the results of the first evaluation of the knowledge collected by these tools. the evaluation was performed by complementing the tools with a fully functional expert system that accepted the generated knowledge bases and allowed experts to test the completeness of the knowledge through a series of interactive consultations. the knowledge base used for this evaluation was derived from the text for the italian value added tax law. the text was pre- processed in its ascii form by the nomos tools and the generated knowledge base was filtered through to a conventional expert system shell to generate the evaluation expert system.  knowledge extracted directly from text was converted into a hybrid of production rules and conceptual graphs. [see sowa 1984] knowledge collected from other sources, such as previously resolved cases, explanations of terms and examples, were linked to the knowledge base using an automated hypertext technique. [see konstantinou & morse 1992] finally, the expert system was tested using real-life cases supplied by the italian ministry of finance.  vassilis konstantinou john sykes georgios n. yannopoulos
photorealistic rendering of knitwear using the lumislice  we present a method for efficient synthesis of photorealistic free-form knitwear. our approach is motivated by the observation that a single cross- section of yarn can serve as the basic primitive for modeling entire articles of knitwear. this primitive, called the _lumislice_, describes radiance from a yarn cross-section based on fine-level interactions --- such as occlusion, shadowing, and multiple scattering --- among yarn fibers. by representing yarn as a sequence of identical but rotated cross-sections, the lumislice can effectively propagate local microstructure over arbitrary stitch patterns and knitwear shapes. this framework accommodates varying levels of detail and capitalizes on hardware-assisted transparency blending. to further enhance realism, a technique for generating soft shadows from yarn is also introduced.  ying-qing xu yanyun chen stephen lin hua zhong enhua wu baining guo heung- yeung shum
the warpengine: an architecture for the post-polygonal age  we present the warpengine, an architecture designed for real-time imaged-based rendering of natural scenes from arbitrary viewpoints. the modeling primitives are real- world images with per-pixel depth. currently they are acquired and stored off- line; in the near future real-time depth-image acquisition will be possible, the warpengine is designed to render in immediate mode from such data sources.  the depth-image resolution is locally adapted by interpolation to match the resolution of the output image. 3d warping can occur either before or after the interpolation; the resulting warped/interpolated samples are forward- mapped into a warp buffer, with the precise locations recorded using an offset. warping processors are integrated on-chip with the warp buffer, allowing efficient, scalable implementation of very high performance systems. each chip will be able to process 100 million samples per second and provide 4.8gigabytes per second of bandwidth to the warp buffer.  the warpengine is significantly less complex than our previous efforts, incorporating only a single asic design. small configurations can be packaged as a pc add-in card, while larger deskside configurations will provide hdtv resolutions at 50 hz, enabling radical new applications such as 3d television.  warpengine will be highly programmable, facilitating use as a test-bed for experimental ibr algorithms.  voicu popescu john eyles anselmo lastra joshua steinhurst nick england lars nyland
panel session: improving the teaching of simulation  the diversity of application areas represented at a typical simulation conference attests to the increased usage of computer simulation, however, increased usage may lead to a decrease in the overall "quality" of simulations. in an effort to improve simulation quality, research continues in methodology areas such as documentation, validity, and statistical techniques.  another constant concern is the manner in which computer simulation is being taught by educational institutions and private companies. the development of sophisticated simulation languages has made simulation a practical decision making tool, but often the apparent simplicity of a language leads to deficiencies in the teaching of basic methodology. all practitioners of simulation should feel a responsibility to work toward improving the quality of teaching in the field.  carl j. bellas lewis corner a alan b pritsker thomas schriber
design of simulation models  the organizer of this panel has chosen to address this difficult subject by experience. the four invited panelists average 20 years of experience in the field of simulation. they represent the users and the builders of simulation models, both private industry and government, and are familiar with a diversity of languages used in modeling.  each panelist has been invited to give a fifteen minute presentation drawing of their unique perspective of the design of simulation models. following the presentation, a period will be provided for discussion and questions.  donald a. heimburger julian reitman henry kleine otis l. newton howard l. swaim
surfels: surface elements as rendering primitives  surface elements (surfels) are a powerful paradigm to efficiently render complex geometric objects at interactive frame rates. unlike classical surface discretizations, i.e., triangles or quadrilateral meshes, surfels are point primitives without explicit connectivity. surfel attributes comprise depth, texture color, normal, and others. as a pre-process, an octree-based surfel representation of a geometric object is computed. during sampling, surfel positions and normals are optionally perturbed, and different levels of texture colors are prefiltered and stored per surfel. during rendering, a hierarchical forward warping algorithm projects surfels to a z-buffer. a novel method called visibility splatting determines visible surfels and holes in the z-buffer. visible surfels are shaded using texture filtering, phong illumination, and environment mapping using per-surfel normals. several methods of image reconstruction, including supersampling, offer flexible speed-quality tradeoffs. due to the simplicity of the operations, the surfel rendering pipeline is amenable for hardware implementation. surfel objects offer complex shape, low rendering cost and high image quality, which makes them specifically suited for low-cost, real-time graphics, such as games.  hanspeter pfister matthias zwicker jeroen van baar markus gross