Hand-sketching is a particularly attractive solution to providing an intuitive design interface for modeling. The goal is to reduce the data collected from the input strokes and to construct a curve that faithfully re...
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A highly parallel technique for linking line segments into curved contours or boundaries has been developed. This bottom-up organization of the line segments utilizes information in the line data itself and perceptual...
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Accurate simulation of Newtonian mechanics is essential for simulating realistic motion of joined figures. Dynamic simulation requires, however, a large amount of computation when compared to kinematic methods, and th...
ISBN:
(纸本)9780897913447
Accurate simulation of Newtonian mechanics is essential for simulating realistic motion of joined figures. Dynamic simulation requires, however, a large amount of computation when compared to kinematic methods, and the control of dynamic figures can be quite complex. We have implemented an efficient forward dynamic simulation algorithm for articulated figures which has a computational complexity linear in the number of joints. In addition, we present a strategy for the coordination of the locomotion of a six-legged figure - a simulated insect - which has two main components: a gait controller which sequences stepping, and motor programs which control motions of the figure by the application of forces. The simulation is capable of generating gait patterns and walking phenomena observed in nature, and our simulated insect can negotiate planar and uneven terrain in a realistic manner. The motor program techniques should be generally applicable to other control problems.
The computer-aided fabrication environment (CAFE) is a software system being developed at MIT for use in the manufacture of integrated circuits. CAFE is intended to be used in all phases of process design, development...
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The computer-aided fabrication environment (CAFE) is a software system being developed at MIT for use in the manufacture of integrated circuits. CAFE is intended to be used in all phases of process design, development, planning, and manufacturing of integrated-circuit wafers. The CAFE architectural framework supports a wide variety of software modules, including both development tools and online applications. The key components of the CAFE architecture are the data model and database schema, the process flow and wafer representations, the user interface, and the application programming and database interfaces. All CAFE application modules store and retrieve persistent data through a common database interface layer. Interface wrappers provide seamless, transparent integration of external tools and packages which have their own internal data formats.< >
This paper presents an innovative way of animating actors at a high level based on the concept of synthetic vision. The objective is simple: to create an animation involving a synthetic actor automatically moving in a...
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作者：
CALVERT, TERODRIGUEZ, FASLEBZAK, JSThomas E. Calvert
P.E.: is a senior project engineer with the Propulsion and Auxiliary Systems Department David Taylor Research Center Annapolis Md. His interests include application of computers to all aspects of engineering with particular emphasis on utilization of small computers. Mr. Calvert is a licensed professional engineer in Maryland. He received a BSEE from Drexel University in 1969 and since that time has completed a number of graduate courses related to machinery acoustics. Francisco A. Rodriguez:is an engineer with the Propulsion and Auxiliary Systems Department
David Taylor Research Center. He was formerly with the Computer-Aided Design/Interactive Graphics Group of the Division of Engineering and Weapons U.S. Naval Academy. His interests include interfacing the computer aided design to the computer aided manufacturing along with related software and hardware development. Mr. Rodriguez received a BSEEfrom the University of Virginia in 1968. James S. Slebzak:is a mechanical engineering technician with the Propulsion and Auxiliary Systems Department
David Taylor Research Center. He received his machinists papers in 1971 after serving his apprenticeship at David Taylor Research Center. He continued his education and became the senior numerical control programmer at the Annapolis Laboratory. He completed his mechanical technology degree from Anne Arundel Community College in 1986. His interests are in the application of numerically controlled manufacturing techniques to prototype machinery components.
The machine shop at the Annapolis Laboratory of the David Taylor Research Center (DTRC) provides model making and prototype support to a large variety of naval ship related engineering projects. In order to meet these...
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The machine shop at the Annapolis Laboratory of the David Taylor Research Center (DTRC) provides model making and prototype support to a large variety of naval ship related engineering projects. In order to meet these challenging requirements, computer aided design/computer aided manufacturing (CAD/CAM) techniques are being used to produce “one of a kind” prototypes or very low volume production parts. The use of computer aides in these cases is to facilitate the accurate manufacture of a difficult part, rather than to improve manufacturing efficiencies. In addition, the approach provides the flexibility required to support research and development projects. Several examples of prototype shipboard components manufactured using CAD/CAM techniques are presented in this paper. The hardware and software that facilitated these projects are discussed. The examples described have met the requirements to produce a wide variety of prototype shipboard machinery components quickly and accurately.
In this paper we describe the evolution of a whole-hand interface to our virtual-environment graphical system. We present a set of abstractions that can be used to implement device-independent interfaces for hand meas...
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ISBN:
(纸本)0897913353
In this paper we describe the evolution of a whole-hand interface to our virtual-environment graphical system. We present a set of abstractions that can be used to implement device-independent interfaces for hand measurement devices. Some of these abstractions correspond to known logical device abstractions, while others take further advantage of the richness of expression in the human hand. We describe these abstractions in the context of their use in our development of virtual environments.
A solid noise is a function that defines a random value at each point in space. Solid noises have immediate and powerful applications in surface texturing, stochastic modeling, and the animation of natural phenomena. ...
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ISBN:
(纸本)0897913124
A solid noise is a function that defines a random value at each point in space. Solid noises have immediate and powerful applications in surface texturing, stochastic modeling, and the animation of natural phenomena. Existing solid noise synthesis algorithms are surveyed and two new algorithms are presented. The first uses Wiener interpolation to interpolate random values on a discrete lattice. The second is an efficient sparse convolution algorithm. Both algorithms are developed for model-directed synthesis, in which sampling and construction of the noise occur only at points where the noise value is required, rather than over a regularly sampled region of space. The paper attempts to present the rationale for the selection of these particular algorithms. The new algorithms have advantages of efficiency, improved control over the noise power spectrum, and the absence of artifacts. The convolution algorithm additionally allows quality to be traded for efficiency without introducing obvious deterministic effects. The algorithms are particularly suitable for applications where high-quality solid noises are required. Several sample applications in stochastic modeling and solid texturing are shown.
Three-dimensional restitution of images with unconventional imaging geometry can be performed in an operational mode using existing commercial analytical plotters without any extra investments in hardware. The paper p...
Three-dimensional restitution of images with unconventional imaging geometry can be performed in an operational mode using existing commercial analytical plotters without any extra investments in hardware. The paper presents two programme systems developed for the Kern DSR analytical stereo-plotter for mapping with spaceborne stereo-imagery, one for images acquired by the SPOT HRV sensor, the other one for stereo-mensuration of SAR images. Due to the movement of the satellite platforms the software requires appropriate algorithms for the consideration of time-varying orientation parameters like sensor position, sensor attitude or others. The performance of the programme systems is demonstrated with practical results derived from Space Shuttle SIR-B imagery as well as from SPOT images showing realistically achievable accuracies of a few pixels in planimetry.
Current radiosity methods rely on the calculation of geometric factors, known as form-factors, which describe energy exchange between pairs of surfaces in the environment. The most computationally efficient method for...
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ISBN:
(纸本)0897913124
Current radiosity methods rely on the calculation of geometric factors, known as form-factors, which describe energy exchange between pairs of surfaces in the environment. The most computationally efficient method for form-factor generation is a numerical technique known as the hemi-cube algorithm. Use of the hemi-cube is based on assumptions about the geometry of the surfaces involved. First, this paper examines the types of errors and visual artifacts that result when these assumptions are violated. Second, the paper shows that these errors occur more frequently in progressive refinement radiosity than in the originally proposed full matrix radiosity solution. Next, a new analytical technique for determining form-factors that is immune to the errors of the hemicube algorithm is introduced. Finally, a hybrid progressive refinement method that invokes the new technique to correctly compute formfactors when hemi-cube assumptions are violated is presented.
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