ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1986.tb00313.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractThe Programmer's Hierarchical Interactive Grahics System (PHIGS) specifies an interface for programming device‐independent computer graphics applications. PHIGS provides a powerful data grouping mechanism, called the PHIGS structure, that may be used to model the geometry of 3D objects. Hidden Line/Hidden Surface Removal (HL/HSR) is a required process to produce realistic solid views of the modeled objects. Modeling clip is an essential process for viewing a clipped portion of the modeled objects. A technique is presented that provides HL/HSR and modeling clip as added utilities to PHIGS. The technique is based on the Binary Space Partitioning (BSP) tree (sometimes called priority tree), and involves a back to front sorting of the primitives of a PHIGS structure network to another PHIGS structure. Modeling clip is achieved by limiting the sorting to those primitives in a specified clip ping region of the object space. The resulting structure when displayed on a raster device produces a realistic view of the possibly clipped object that was originally modeled by the PHIGS structure networ

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1986.tb00314.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractHershey's “Repertory of Occidental Fonts” is well known in the field of computer graphics, as a set of character‐forms which is superior to the cruder representations used when space was at a premium. This paper gives a method of extending Hershey's format to include true curves, thus giving near typographical qu

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1986.tb00315.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractWe investigate the benefits of using a functional language to reason about and to implement animation. Since animation concerns pictures changing over time, we consider the manipulation ofmoviesor picture sequences. A compact set of primitive operations over movies is introduced and its use as the basis for an animation system is illustrated. The notion of thebehaviourof an animated character is formalised and we show how simple behaviours may be combined to create more complex behaviours. We then show how higher‐order functions allow us to construct a variety of useful tools which lead to a highly concise functional scrip

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1986.tb00316.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractA computer graphics algorithm is used to create complicated forms resembling invertebrate organisms. These natural morphologies are generated through the iteration of mathematical transformations. Several illustrations are chosen as examples of the diversity of biological structures which result from this technique.

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1986.tb00317.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractAn algorithm for automatic reconstruction of 3D objects from their orthographic projections is presented in this paper. It makes some improvements to, and complements the, Wesley‐Markowsky algorithm, which is a typical hierarchical reconstruction algorithm limited to polyhedral objects, and extracts the idea of pattern recognition expressed in the Aldefeld algorithm. It is shown in theory by analysis and in practice by implementation that the proposed algorithm successfully rejected pathological cases and found all solutions with the same set of orthographic views. Compared with the existing algorithms presented in references, this algorithm covers some more complex cases of objects incorporating cylinder

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1986.tb00318.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1986.tb00319.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

摘要:

AbstractRecent developments in hardware and software have led to the production of complex computer‐generated images and films. Sophisticated algorithms like ray‐tracing, fractals or particle systems allow the generation of very realistic natural scenes. However, the design of images and films is still a painful task for designers, because of the inadequacy of person‐machine interfaces. A large number of parameters is necessary to build objects (curves, surfaces) to define their properties (orientation, size, colour, transparency, texture, reflectance), to specify the viewing angle, to control the lights and shadows, to define and synchronize motions.The technology of artificial intelligence and more specially knowledge engineering makes possible the development of intelligent human‐machine interfaces for image synthesis and animation. Designers may communicate with design and animation systems using natural language. Basic geometric rules may be given to the computer, making it an expert in 3D geometric modeling. Languages based on the concept of frame simplify the intelligent description of complex objects. Expert systems allow the designer to specify the conditions of an image using goal‐directed specifications for cameras and lights. Scripts and actors are particularly appropriate for the description of motions; the impact of these concepts on 3D computer animation is considerable. Finally, the complex problem of animation of articulated bodies may be solved using knowledge‐based animation. Examples are presented using our new language EXPERTMIRA. This language is based on MIRA and PROLOG and incorporates concepts of artificial intelligence, image synthesis an

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1986.tb00320.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1986.tb00321.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY

ISSN:0167-7055    

DOI:10.1111/j.1467-8659.1986.tb00322.x

出版商:Blackwell Publishing Ltd    

年代:1986

数据来源: WILEY