Abstract: The film accompanied by this paper illustrates an experimental system for real-time Computer-Aided Geometric Design of three-dimensional parametric surfaces. A detailed description of the system is given in another paper by the author(1). Its principle features are that it operates in real-time, all geometric interaction with the surfaces is accomplished with a 3-D Wand, the surfaces are viewed in 3-D using a head-mounted display, and the surfaces are mathematically represented using parametric spline surface patches.The two principle computing components of the system are a PDP-10 computer and an LDS-1 display computer. The PDP-10 acts as a host to the LDS-1. Its main tasks each 1/30 second are to compute the 3-D Wand and head-mounted display positions and to incrementally update the geometries of the surface patches being designed by the user. During the same time period, the LDS-1 loads its digital matrix multiplier with the room-to-head transformation matrix provided to it by the PDP-10, displays on the head-mounted display's CRT's a line drawn rendering of all of the parametric surface patches that are within the 40 degree field-of-view of the display and displays a small cube to represent the current position of the Wand.The user of the system initiates a design sequence by selecting a patch description file from the PDP-10's file system. He then puts on the head-mounted display and uses the 3-D Wand with its control buttons to grasp the patches, which appear to float before him in the room, and make appropriate changes to their geometry. After a design sequence he may save the new surfaces on the PDP-10 file system and select certain views of the surfaces to be rendered as a continuous-tone shaded picture with hidden-surfaces removed.The first part of the film described here shows the system in real-time operation. During this part, several free-form surfaces are manipulated as the camera records the action on a line-drawing monitor. The second part of the film illustrates a continuous-tone, shaded rendering of a design sequence. The continuous-tone rendering was produced "off-line" using pertinent viewpoint information that was saved during the design sequence. The final few minutes of the film depict the construction of a Klein-Bottle.

Abstract: In 1974 Ed Catmull developed a new algorithm for rendering images of bivariate surface patches. This paper describes extensions of this algorithm in the areas of texture simulation and lighting models.The parametrization of a patch defines a coordinate system which is used as a key for mapping patterns onto the surface. The parametric values within each picture element are input to a pattern definition function. A weighted average of the values of this function over the picture element scales the intensity of that picture element. By suitably defining the pattern function, various surfaces textures can be simulated. The shape and size of this weighting function is chosen using digital signal processing theory.The other problem addressed here concerns lighting models. The patch rendering algorithm allows accurate computation of the surface.

Abstract: The problem of the initial transient has received much attention in the simulation literature. However, much of it is replete with ambiguous admonitions rendering it virtually useless to the average practitioner. In this paper we present a comprehensive framework for this problem within which a systematic study may be pursued and eventually produce some well-defined, comprehensible, and meaningful methods that a simulator can apply to his particular problem. More specifically, we give 1) a precise definition of the problem, 2) a set of criteria by which solutions may be evaluated, and 3) a description of the studies underway within the framework established in 1) and 2).

Abstract: This device is for use in the martial arts such as karate. The device consists primarily of a pair of units with handle grip means and clamp means for rendering a multiple number of wooden boards stationary, so as to be broken simultaneously.

Abstract: PURPOSE: To change the magnification with no change of visibility by shifting a finder optical system along its optical axis, and rendering a portion of the optical system to go forward and backward along the optical axis. COPYRIGHT: (C)1977,JPO&Japio

Abstract: PURPOSE: To stop the energization to the circuit of camera in response to the reduction of voltage by rendering the output of voltage detection circuit to memorize in the memory means, and controlling the control of energizing switching means with the output of the memory means. COPYRIGHT: (C)1977,JPO&Japio

Abstract: Electronic-photography light-sensitive material provided with a light-sensitive material layer suitable for rendering of continuous gradation of tones.

Abstract: There is a need for ranking the colour rendering properties of light sources. These properties can be specified using the test colour method. Considering only ideal systems the ranking of 20 spectrally widely diverse light sources was determined. The ideal systems are not however representative of good practice. The incorporation of a linear matrix makes the practical system less sensitive to differences in chromaticity. Thus, scene illuminants with various colour temperatures may give good colour reproduction. The correlation between the rankings obtained with several practical systems increases as the systems give better colour reproduction of a scene under standard illumination. Therefore the ranking method should use only 'good practice' systems. It was found that a set of 16 test colours may be considered as representative of the total set of 39 test colours.