ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1985.tb00216.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1985.tb00217.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract3D computer input has been a recurring challenge to engineers developing effective CAD systems. The approach adopted in this paper attempts to address a specific type of 3D input which is applicable to architecture and some engineering design tasks. In these processes, the object being designed is often an assembly of defined components. In a conventional graphics based CAD system these components are usually represented by graphical Icons which are displayed on the graphics screen and are arranged by the user. The system described here consists of 3D modelling elements which the user physically assembles to form his design. Each modelling element contains an element processor consisting of a machine readable label, data paths and control logic. The CAD system interrogates the elements. The logic within the element processors and the data paths are then used to interrogate other adjacent elements in the model. This system can therefore be considered as a “user generated”“machine readable” modelling system. In an architectural application this provides the user with a system of 3D Icons with which to model and evaluate the built envi

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1985.tb00218.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe Space Telescope Faint Object Camera is one of the most exciting projects in astronomical history, and will expand the volume of the observable universe by a factor of almost one thousand. In order to process the images from this instrument a FOC Image Processing System (FIPS) has been developed at the European Space Technology Centre (ESTEC) in Holland.Amongst other features, such as means to input, display, store, retrieve and output image and graphics data, FIPS places much emphasis on the user interface. The FIPS Command Language (FCL) is based on algorithmic languages such as PASCAL, C, ALGOL, etc, rather than conventional Job Control Languages, and thus includes control statements, compound statements, functions and procedures, assignment statements, etc. These allow the user to define complex functions out of the basic commands and to process for example, sets of images and graphics files without intervention.In addition, FCL allows command parameters to be specified either by default, canonically, by means of keywords, or via prompts to take account of the experience of the user. HELP information can be invoked both at the command and parameter levels, to assist the inexperienced user. As image processing can be time consuming, certain operations (e.g. rotate an image) can be performed asynchronously to avoid delaying interactive user input.Some examples of the practical usage of FIPS are also given, and the paper concludes with an assessment of how well FIPS has met its objectives and what improvements would be beneficial.FIPS is available on a commercial basis from Dynaflow Software Systems. For further information contact J Gras at the address indicated.

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1985.tb00219.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe authors describe a method of presenting colour pictures which allows users to browse by panning and zooming. The pictures are seen as though on a 512 by 512 by 12 bit framestore, but are defined to 4096 by 4096. The implementation allows the entire picture to be seen in overview, with fine details averaged, or to be zoomed in upon with finer detail progressively revealed by a sequence of twofold linear magnifications. Further zooming, beyond the resolution of the picture data, automatically produces a conventional pixel replication effect. In addition, the picture may be panned vertically or horizontally.

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1985.tb00220.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThe interference of superposed families of curves is considered, for various types of superposition available through computer graphics. It is shown that the use of interference of this type for illustration and experimentation in hydrodynamics, optics, and in certain other situations, is rather limited. To use the technique of superposition most effectively in these areas it is found to be necessary to eliminate the interference, and to use cine techniques.

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1985.tb00221.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractOne of the standard methods of simplifying the task of obtaining a shaded image of a solid object is to represent it by a polyhedron. Another method is to use sculptured surface modelling which represents surfaces by collections of surface patches. Using either method the surfaces can be approximated by facets, which are simple to shade according to photometry information.To obtain a smooth image in regions of high curvature, the surface would typically be required to have hundreds or thousands of facets. Because of the large number of facets involved, it is extremely important that geometrical and topological information is stored in an efficient manner. This information must include all that is required for an unambiguous representation of the solid(s) in question.The compressed data structure (CDS) is suitable for this purpose, and is capable of defining the majority of surfaces. The structure is intended to minimise the amount of data stored, with as much information as possible being implied. The CDS can be easily generated knowing the order of the vertices defining the surface.

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1985.tb00222.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractThis paper presents formulae and results from a practical implementation of a conic arc specified in terms of its end‐points and other descriptors, based on the three numeric factors,bulge, shearandsquash, described in an earlier paper. The parametric form for the derivative is given, from which are found the normals from a given point to the arc, and formulae for splitting off one or more parts from it. A method of chordal approximation for plotting purposes is also presented, and the effects of applying transformations are discusse

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1985.tb00223.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractMOSS4 is a proposed language extension which allows the creation of systems that model rigid solids in three dimensions and their movement over time, the fourth dimension. MOSS4 allows the creation of completely independent objects that execute in parallel and communicate using message passing. Each object contains a hierarchy of components which are related to each other via common coordinate spaces, and by joints and constraints. The user can create joint types plus the operations defined on them which then apply to the solid the joint is combined with. The system that MOSS4 generates can switch between realtime and stop‐frame modes dynamically, and the user can generate synchronisation points to ensure consistency between independently executing object

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1985.tb00224.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

AbstractA method for generating new device drivers for use in a full GKS implementation is presented. The method is based on conditional compiling techniques making use of the Workstation Description Table, and it has been used in a full GKS to develop several device drivers, which took about 1 week for a novice.

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1985.tb00225.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY