Issue 2
Permanent URI for this collection
Browse
Browsing Issue 2 by Title
Now showing 1 - 13 of 13
Results Per Page
Sort Options
Item All Articles(Blackwell Publishers Ltd and the Eurographics Association, 1998) -Item Book Reviews(Blackwell Publishers Ltd and the Eurographics Association, 1998)Strasser, W., Klein, R. and Rau, R. (editors). Geometric Modelling: Theory and PracticeSchonhut, Jurgen. Document Imaging: Computer Meets PressStocker, Gerfried and Schopf, Christine (editors). Fleshfactor: Informationsmaschine MenschMcCullough, Malcolm. Abstracting Craft: The Practiced Digital HandOâ Quinn, Donnie and Leclair, Matt. Photoshop in a NutshellMerz, Thomas. PostScript and Acrobat/PDFStrothotte, Thomas and Strothotte, Christine. Seeing between the Pixels: Pictures in Interactive SystemsItem Calendar of Events(Blackwell Publishers Ltd and the Eurographics Association, 1998) Greiner, GuntherItem Creating and Rendering Convolution Surfaces(Blackwell Publishers Ltd and the Eurographics Association, 1998) McCormack, Jon; Sherstyuk, AndreiImplicit surfaces obtained by convolution of multi-dimensional primitives with some potential function, are a generalisation of popular implicit surface models: blobs, metaballs and soft objects. These models differ in their choice of potential function but agree upon the use of underlying modelling primitives, namely, points. In this paper a method is described for modelling and rendering implicit surfaces built upon an expanded set of skeletal primitives: points, line segments, polygons, arcs and planes. An analytical solution to the convolution is described. This solution offers a more accurate and robust representation of the resultant implicit surface than previous methods. An algorithm for ray-tracing the surfaces formed through convolution of any combination of these primitives is also outlined.Item Editorial(Blackwell Publishers Ltd and the Eurographics Association, 1998) Coquillart, Sabine; Seidel, Hans-PeterItem Fast Collision Detection Algorithms with Applications to Particle Flow(Blackwell Publishers Ltd and the Eurographics Association, 1998) Vemuri, B. C.; Cao, Y.; Chen, L.In this paper, we present efficient algorithms for collision detection of arbitrarily shaped rigid moving objects in a variety of interactive as well as non-interactive environments. The algorithms primarily consist of two stages. The first stage involves finding candidate objects for possible collisions. The second stage involves detecting exact (within a prespecified tolerance) collision between these candidates. The primary data structure used in the algorithms is an octree. In the first stage, we build an octree for the enclosure containing the objects, which is used to detect possible collisions. Assuming spatial/temporal coherence i.e., that the particles move slowly or that the time sampling is fast enough, the average time complexity of this stage can be shown to be O(n) (excluding the time complexity for a one time octree construction), where n is the number of particles. In the second stage, we build a surface-octree for each object. If the objects are convex and assuming coherence, the expected time complexity to detect precise (within a prespecified tolerance) collision for each pair is a constant (excluding the time complexity for a one time surface-octree construction). Therefore, the overall expected time complexity for convex object collision detection is linear with respect to n. For the concave objects, complexity analysis is nontrivial to perform and instead we provide a very practical (almost linear time) algorithm. We apply our algorithms to particle flow simulations by simulating flow density conditions often arising in granular flows.Item Fifth Eurographics Workshop on Design Specification and Verification of Interactive Systems, Abingdon, UK, June 3-5 1998(Blackwell Publishers Ltd and the Eurographics Association, 1998) Markopoulos, P.; Johnson, P.Item Interactive Construction and Animation of Layered Elastically Deformable Characters(Blackwell Publishers Ltd and the Eurographics Association, 1998) Turner, Russell; Gobbetti, EnricoAn interactive system is described for creating and animating deformable 3D characters. By using a hybrid layered model of kinematic and physics-based components together with an immersive 3D direct manipulation interface, it is possible to quickly construct characters that deform naturally when animated and whose behavior can be controlled interactively using intuitive parameters. In this layered construction technique, called the elastic surface layer model, a simulated elastically deformable skin surface is wrapped around a kinematic articulated figure. Unlike previous layered models, the skin is free to slide along the underlying surface layers constrained by geometric constraints which push the surface out and spring forces which pull the surface in to the underlying layers. By tuning the parameters of the physics-based model, a variety of surface shapes and behaviors can be obtained such as more realistic-looking skin deformation at the joints, skin sliding over muscles, and dynamic effects such as squash-and-stretch and follow-through. Since the elastic model derives all of its input forces from the underlying articulated figure, the animator may specify all of the physical properties of the character once, during the initial character design process, after which a complete animation sequence can be created using a traditional skeleton animation technique. Character construction and animation are done using a 3D user interface based on two-handed manipulation registered with head-tracked stereo viewing. In our configuration, a six degree-of-freedom head-tracker and CrystalEyes shutter glasses are used to display stereo images on a workstation monitor that dynamically follow the user head motion. 3D virtual objects can be made to appear at a fixed location in physical space which the user may view from different angles by moving his head. To construct 3D animated characters, the user interacts with the simulated environment using both hands simultaneously: the left hand, controlling a Spaceball, is used for 3D navigation and object movement, while the right hand, holding a 3D mouse, is used to manipulate through a virtual tool metaphor the objects appearing in front of the screen. Hand-eye coordination is made possible by registering virtual space to physical space, allowing a variety of complex 3D tasks necessary for constructing 3D animated characters to be performed more easily and more rapidly than is possible using traditional interactive techniques.Item Join Now!(Blackwell Publishers Ltd and the Eurographics Association, 1998)Item Metro: Measuring Error on Simplified Surfaces(Blackwell Publishers Ltd and the Eurographics Association, 1998) Cignoni, P.; Rocchini, C.; Scopigno, R.This paper presents a new tool, Metro, designed to compensate for a deficiency in many simplification methods proposed in literature. Metro allows one to compare the difference between a pair of surfaces (e.g. a triangulated mesh and its simplified representation) by adopting a surface sampling approach. It has been designed as a highly general tool, and it does no assumption on the particular approach used to build the simplified representation. It returns both numerical results (meshes areas and volumes, maximum and mean error, etc.) and visual results, by coloring the input surface according to the approximation error.Item Network Service(Blackwell Publishers Ltd and the Eurographics Association, 1998)Item Ninth Eurographics Workshop on Visualization in Scientific Computing, Blaubeuren, Germany, April 20-22 1998(Blackwell Publishers Ltd and the Eurographics Association, 1998) Duce, D. A.Item Tree Visualisation and Navigation Clues for Information Visualisation(Blackwell Publishers Ltd and the Eurographics Association, 1998) Herman, Ivan; Delest, Maylis; Melancon, GuyInformation visualisation often requires good navigation aids on large trees, which represent the underlying abstract information. Using trees for information visualisation requires novel user interface techniques, visual clues, and navigational aids. This paper describes a visual clue: using the so-called Strahler numbers, a map is provided that indicates which parts of the tree are interesting. A second idea is that of "folding" away subtrees that are too "different" in some sense, thereby reducing the visual complexity of the tree. Examples are given demonstrating these techniques, and what the further challenges in this area are.