The authors have developed a modeling system Do in three dimensional computergraphics (3D-CG) that, by verbal instructions in natural language, models geometrical shapes and renders the images. The former system is b...
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ISBN:
(纸本)1595935649
The authors have developed a modeling system Do in three dimensional computergraphics (3D-CG) that, by verbal instructions in natural language, models geometrical shapes and renders the images. The former system is based on a step-by-step construction scheme using static instructions and a static display, that is, a static verbal instruction creates a static scene and an image. This static-based system scheme has a critical limitation at the conversation stage between a user and the system. In this paper, the authors propose a dynamic instruction and dynamic display methods for the modeling system. First, the dynamic display enables users to watch the animation indicating the change between the previous geometries and the next geometries with smooth transition during the execution of an instruction from the user. Second, the dynamic instruction enables users to give the next instruction before the animation ends. For those purposes, two geometrical transformation methods by affine transformation: (a) with a common difference matrix, and (b) with a common ratio matrix, are introduced and studied to generate frames for the animation. The proposed methods are implemented and evaluated by some experiments. The changes between instructions are observed naturally by the common ratio matrix method.
The panelists will share their experiences in developing closed laboratory exercises for lower level CS courses with particular emphasis on using graphical presentation techniques as a pedological and motivational too...
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ISBN:
(纸本)0897916468
The panelists will share their experiences in developing closed laboratory exercises for lower level CS courses with particular emphasis on using graphical presentation techniques as a pedological and motivational tool. The use of interactive animations and visualization is combined with structured support for the student programmer to provide an apprentice style learning environment. Three major threads form the backbone of this curriculum. The first is the use of interactive animations and experimentation programs to introduce and illustrate dynamic processes - e.g. algorithm behavior, or changes in data structures over a period of time. The second thread is the use of graphics in student programs, not only as motivation, but also as a visual feedback and debugging tool. The third thread tying all together is the extensive use of model programs, shell drivers, toolkits, and procedures that encapsulate abstractions. These programming tools support the apprentice style of learning and illustrate good software design and practice throughout the curriculum.
In computergraphics, most algorithms for sampling implicit surfaces use a 2-points numerical method. If the surface-describing function evaluates positive at the first point and negative at the second one, we can say...
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ISBN:
(纸本)1595935649
In computergraphics, most algorithms for sampling implicit surfaces use a 2-points numerical method. If the surface-describing function evaluates positive at the first point and negative at the second one, we can say that the surface is located somewhere between them. Surfaces detected this way are called sign-variant implicit surfaces. However, 2-points numerical methods may fail to detect and sample the surface because the functions of many implicit surfaces evaluate either positive or negative everywhere around them. These surfaces are here called sign-invariant implicit surfaces. In this paper, instead of using a 2-points numerical method, we use a 1-point numerical method to guarantee that our algorithm detects and samples both sign-variant and sign-invariant surface components or branches correctly. This algorithm follows a continuation approach to tessellate implicit surfaces, so that it applies symbolic factorization to decompose the function expression into symbolic components, sampling then each symbolic function component separately. This ensures that our algorithm detects, samples, and triangulates most components of implicit surfaces.
We present two approaches to the problem of calculating a cell in a 3-dimensional arrangement of quadrics. The first approach solves the problem using rational arithmetic. It works with reductions to planar arrangemen...
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We present two approaches to the problem of calculating a cell in a 3-dimensional arrangement of quadrics. The first approach solves the problem using rational arithmetic. It works with reductions to planar arrangements of algebraic curves. Degenerate situations such as tangential intersections and self-intersections of curves are intrinsic to the planar arrangements we obtain. The coordinates of the intersection points are given by the roots of univariate polynomials. We succeed in locating all intersection points either by extended local box hit counting arguments or by globally characterizing them with simple square root expressions. The latter is realized by a clever factorization of the univariate polynomials. Only the combination of these two results facilitates a practical and implementable algorithm. The second approach operates directly in 3-space by applying classical solid modeling techniques. Whereas the first approach guarantees a correct solution in every case the second one may fail in som e degenerate situations. But with the help of verified floating point arithmetic it can detect these critical cases and is faster if the quadrics are in general position.
The effective use of GPUs for accelerating applications depends on a number of factors including effective asynchronous use of heterogeneous resources, reducing memory transfer between CPU and GPU, increasing occupanc...
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A comparative study of different network techniques has shown the various relations among them, and has allowed to sum up facts on interactivegraphics in modeling. Starting from such elements, we can conceive a softw...
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A comparative study of different network techniques has shown the various relations among them, and has allowed to sum up facts on interactivegraphics in modeling. Starting from such elements, we can conceive a software unifying the stochastic models (Q-GERT), the dynamic models (Systems dynamics), the parallel models (Petri nets), the critical paths models (PERT) and the structural models (DELTA charts, ISM). We indicate the organization of the software with emphasis on the data structure, the algorithms for operation and control, and the languages pictorial for the description and textual for the control of simulation and service. We explain how it works and describe its implementation environment as well as the necessary features (computer independence, modularity, evolutivity, and personification) together with the conditions for their endownment. We review possible fields of application of the software and illustrate, with a ferm land regrouping project, how to use some of the stated models in a given problem considered at various complexity levels.
Graphic designers often need to find suitable pieces of music for their motion graphic designs, animations, etc. Existing music collection search tools and techniques are at best only suitable for ordinary users, and ...
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ISBN:
(纸本)1595938362
Graphic designers often need to find suitable pieces of music for their motion graphic designs, animations, etc. Existing music collection search tools and techniques are at best only suitable for ordinary users, and lack powerful mechanisms needed by advanced users such as graphic designers when they are searching for music. To be able to develop such search systems, however, we need to better understand how graphic designers in fact formulate and carry out their search for the right music. Unfortunately very little research has been done in this area. This paper describes a pilot study which was carried out to identify some of the strategies that graphic designers adopt when searching for the music they need. Although the study was rather limited in its scope, nevertheless, it sheds some light on the largely unknown process by which graphic designers search for music.
Sketch recognition is the automated recognition of hand drawn diagrams. Military course-of-action (COA) diagrams are used to depict battle scenarios. The domain of military course of action diagrams is particularly in...
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