Some very impressive results have been obtained in the past few years in plants and trees image synthesis. Some algorithms are largely based on the irregularity and fuzziness of the objects, and use fractals, graftals...
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ISBN:
(纸本)9780897912754
Some very impressive results have been obtained in the past few years in plants and trees image synthesis. Some algorithms are largely based on the irregularity and fuzziness of the objects, and use fractals, graftals or particle systems. Others focus on the branching pattern of the trees with emphasis on morphology. Our concern here is the faithfulness of the models to the botanical nature of trees and plants. We present a model which integrates botanical knowledge of the architecture of the trees: how they grow, how they occupy space, where and how leaves, flowers or fruits are located, etc. The very first interest of the model we propose is its great richness: the same procedural methods can produce "plants" as different as weeping willows, fir trees, cedar trees, frangipani trees, poplars, pine trees, wild cherry trees, herbs, etc. Another very important benefit one can derive from the model is the integration of time which enables viewing the aging of a tree (possibility to get different pictures of the same tree at different ages, accurate simulation of the death of leaves and branches for example). The ease to integrate physical parameters such as wind, the incidence of factors such as insects attacks, use of fertilizers, plantation density, and so on makes it a useful tool for agronomy or botany.
The proceedings contain 32 papers. The topics discussed include: a muscle model for animating three-dimensional facial expression;flocks, herds, and schools: a distributed behavioral model;principles of traditional an...
ISBN:
(纸本)0897912276
The proceedings contain 32 papers. The topics discussed include: a muscle model for animating three-dimensional facial expression;flocks, herds, and schools: a distributed behavioral model;principles of traditional animation applied to 3D computer animation;principles and applications of pencil tracing;fast ray tracing by ray classification;generating antialiazed images at low sampling densities;GRAPE: An Environment to Build;FRAMES: software tools for modeling, rendering and animation of 3D Scenes;the Reyes image rendering architecture;accurate triangulations of deformed, intersecting surfaces;ray tracing complex models;boundary evaluation of non-convex primitives to produce parametric trimmed surfaces;discrete beta-splines;and direct least-squares fitting of algebraic surfaces containing surface tessellations.
A user's mental model of a system should be an important determinant of performance and as well as a means of understanding why particular user errors occur. In particular, experienced users' models should be ...
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ISBN:
(纸本)0897912136
A user's mental model of a system should be an important determinant of performance and as well as a means of understanding why particular user errors occur. In particular, experienced users' models should be in closer agreement with the system than less experienced users' models, and deviations of expert models from the system should correspond to difficulties in performance and suggest ways that system usability could be improved. The present study explored the utility of scaling techniques for defining and comparing user and system models. The results support the assertion that with experience users' mental models approach the system model. However, even experienced users had significant deviations from the system model, leading to predictions of where experts would have difficulty using the system and suggestions for improving usability.
This paper describes the basic principles of traditional 2D hand drawn animation and their application to 3D computer animation. After describing how these principles evolved, the individual principles are detailed, a...
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ISBN:
(纸本)0897912276
This paper describes the basic principles of traditional 2D hand drawn animation and their application to 3D computer animation. After describing how these principles evolved, the individual principles are detailed, addressing their meanings in 2D hand drawn animation and their application to 3D computer animation. This should demonstrate the importance of these principles to quality 3D computer animation.
interactive 3D graphics applications require significant arithmetic processing to handle complex models, particularly if realistic rendering techniques are used. Current semiconductor technology cannot provide the nec...
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ISBN:
(纸本)0897912276
interactive 3D graphics applications require significant arithmetic processing to handle complex models, particularly if realistic rendering techniques are used. Current semiconductor technology cannot provide the necessary performance without some form of multiprocessing. This paper describes a graphics processor architecture which can be configured with an arbitrary number of identical processors operating in parallel. Each of the parallel processors can be programmed identically as if it were a single processor system, substantially simplifying software development and allowing complex rendering functions to take advantage of the multiple processors. The architecture described is able to achieve extremely high performance while allowing the price/performance of the system to be optimized for a given application. techniques are described for handling graphics command distribution, sequencing of commands which must be processed in order, parallel processing of graphics primitive picking, and handling inquiry (readback) commands.
Let scene composition be the precise placement of shapes relative to each other, using affine transformations. By this definition, the steps of scene composition are the selection of objects to be moved, the choice of...
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We present a solution to the aliasing problem for shadow algorithms that use depth maps. The solution is based on a new filtering technique called percentage closer filtering. In addition to antialiasing, the improved...
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ISBN:
(纸本)0897912276
We present a solution to the aliasing problem for shadow algorithms that use depth maps. The solution is based on a new filtering technique called percentage closer filtering. In addition to antialiasing, the improved algorithm provides soft shadow boundaries mat resemble penumbrae. We describe the new algorithm in detail, demonstrate the effects of its parameters, and analyze its performance.
A system for interactively describing and modifying free-form surfaces is presented. The system is based on the use of bicubic patches. Although it is not a full-fledged mechanical CAD system, it has been used to cons...
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