Input preprocessors have come to be recognized as important components of modern finite element programs. A method is described which utilizes interactive computergraphics digitizing techniques to create a powerful i...
详细信息
This paper describes the facilities and operation of the program of computer graphics at Cornell University. A variety of graphic procedures are used for both input and output. The laboratory has the capability for pr...
详细信息
ISBN:
(纸本)9781450373555
This paper describes the facilities and operation of the program of computer graphics at Cornell University. A variety of graphic procedures are used for both input and output. The laboratory has the capability for producing dynamic vector displays and for generating full color images. Numerous research projects in a variety of disciplines which are actively using this multi-user graphics environment are presented.
This paper describes an animation package currently under development at the Cornell program of computer graphics. The basic algorithm employed is linear or non-linear interpolation between successive pairs of key fra...
详细信息
ISBN:
(纸本)9781450373555
This paper describes an animation package currently under development at the Cornell program of computer graphics. The basic algorithm employed is linear or non-linear interpolation between successive pairs of key frames. These key frames are composed of artwork input by the animator on a graphic tablet and displayed on either a black and white vector scope or a color halftone CRT. The initial working environment is two-dimensional, and the individual images are combined using a multiplane cel animation technique to produce depth and motion illusions. Real-time film previewing, utilizing an on-the-fly interpolation algorithm, provides the artist with instant playback of animated sequences.
A polygon hidden surface and hidden line removal algorithm is presented. The algorithm recursively subdivides the image into polygon shaped windows until the depth order within the window is found. Accuracy of the inp...
详细信息
ISBN:
(纸本)9781450373555
A polygon hidden surface and hidden line removal algorithm is presented. The algorithm recursively subdivides the image into polygon shaped windows until the depth order within the window is found. Accuracy of the input data is preserved. The approach is based on a two-dimensional polygon clipper which is sufficiently general to clip a concave polygon with holes to the borders of a concave polygon with holes. A major advantage of the algorithm is that the polygon form of the output is the same as the polygon form of the input. This allows entering previously calculated images to the system for further processing. Shadow casting may then be performed by first producing a hidden surface removed view from the vantage point of the light source and then resubmitting these tagged polygons for hidden surface removal from the position of the observer. Planar surface detail also becomes easy to represent without increasing the complexity of the hidden surface problem. Translucency is also possible. Calculation times are primarily related to the visible complexity of the final image, but can range from a linear to an exponential relationship with the number of input polygons depending on the particular environment portrayed. To avoid excessive computation time, the implementation uses a screen area subdivision preprocessor to create several windows, each containing a specified number of polygons. The hidden surface algorithm is applied to each of these windows separately. This technique avoids the difficulties of subdividing by screen area down to the screen resolution level while maintaining the advantages of the polygon area sort method.
An interactive computergraphics method has been developed for the rapid generation of arbitrary shaped three-dimensional surfaces. The method is a synthesis of spline theory and algorithms, an interactive means for m...
详细信息
GPGS is a subroutine package offering powerful and versatile support for passive and interactive vector graphics? for time-sharing, batch, and stand-alone minicomputer systems. The package is computer, language? and o...
详细信息
GPGS is a subroutine package offering powerful and versatile support for passive and interactive vector graphics? for time-sharing, batch, and stand-alone minicomputer systems. The package is computer, language? and operating system, as well as display device independent. Its key purpose is to allow for transportabiliit of programs and programmers by providing easy to learn, high level features. The applications programmer writes his program once and then executes it on any supported graphics equipment without recompiling} or relinking it. Device-independence oas implemented by dividing GPGSinto a device-"independent part invoked by the applications programmer, and internal, "device drivers"?. one per display device. Like the GSPC "Core System" whose design it influenced, GPGS is a general purpose package. It has a subset of graphics facilities to handle output of line and character primitives with attributes such as line style and character size, aid input from interaction tools such as lightpens, keyboards, valuators, and function keys. It also supports 2D and 3D view point transformations for clipping and window to viewport mapping, and coordinate transforations. Unlike the GSPC Core System, GPGS also includes a set of basic features for modelling objects which alloas definition of device independent masters called seudo picture sSSBSBt These are distinguishedfrca normal, device (DPU) dependent pictur segments into which primitives and their attribute-value settings are ordinarily compiled. These masters may be instanced subject to affine transformations (translate, rotate, and scale) to create a typical oaster-instance hierarchy. The hierarchy may be stored in a disk based library or compiled into a normal picture segment for output to a display device. The images of objects stored in device dependent picture segments may be transformed on the display surface by 2 SKiaaqe transformations. These typically allow use of hardware transformation capabilities for drag
作者：
King, William A.William King has worked with the Navy Training Research Lab in San Diego
California for the past five years and is currently one of the lesson designers in the Computer Assisted Instruction Group. His first association with an educational or training program was as an animator on some of the training films George Pal produced for the Army and Navy during World War II. Since then he has designed graphics and other training materials for Northrop and Astronautics and has performed function and task analyses for determination of training requirements in the Personnel Subsystem Departments of these corporations. Mr. King is a doctoral candidate at the University of Southern California
Floyd Allport's event‐structure theory of behavior is the basis of this model. The process of communication is seen as the changing patterns of events or contacts between the constituent components of a transacti...
暂无评论