Loral Aerospace Corp.

Computer Graphics Systems Development Corporation

Other

Loral Corporation

Cgsd Corporation

Roy Westlake Latham

David R Marsh

Peter O'Driscoll

A method of simulating the appearance of smoke in an electronically generated video image that uses one or more intersecting opaque spheres. Each sphere has a nonuniform smoke density that produces feathered edges. The smoke sphere is an object modeled as a center point (the coordinates of the center of the sphere in three dimensions), a radius (in database coordinates), and a set of parameters that include density and color. The center point is transformed into display screen coordinates, and the radius is transformed into a screen coordinate length. The sphere is projected into a circle in screen coordinates, and a bounding square is generated in screen coordinates that is centered at the sphere center point. The bounding square is then converted into a transparency having color and density attributes added to its data structure. Thus the bounding square has the same data structure as transparent or opaque objects and is processed in the same manner. The transparency is clipped to the boundaries of the display screen. Occlusion processing may then be performed wherein objects located within the smoke cloud are occluded, based upon their relative distance into the cloud. After occlusion processing, a stack of distance-sorted objects are generated to produce an output pixel. If a object has not been occluded for a pixel, it is displayed on the display screen, along with the smoke and other objects. A typical smoke cloud includes several spheres, including one or two large ones that intersect terrain surfaces to appear as hemispheres. The present method forms a smoke cloud that is perspectively invariant, and offers much greater flexibility to provide for dynamic changes in the shape of the smoke cloud.

Computer-implemented method of rendering an image of smoke

A hybrid electric hydraulic drive system, having a first cylinder (75) having a left chamber (32) and a right chamber (34) separated by a piston (22). A second cylinder (76) has a single or sole chamber (74) for receiving hydraulic fluid with the second cylinder enclosing a second piston (78). The second cylinder is substantially equal in length to the first cylinder and is rigidly attached to the first cylinder. A pump (14) is fluidly connected to the left chamber (32) by a first fluid passage (16) and is fluidly connected to the right chamber (34) by a second fluid passage (18). A third fluid passage (80) is directly connected to the right chamber (34) and to the sole fluid chamber (74) of the second cylinder (76). A first rod (30) is connected to the piston (22) and a second rod (84) is connected to the second piston (78). The first and second rods are connected by a connecting element so the rods move in unison. The volume of the sole chamber (74) is equal to the volume of the first rod (30) with the total fluid capacity of the system remaining constant during operation. An encoder (36) is electrically connected to a controller (40) which is electrically connected to a servo electric motor (10) which drives the pump (14).

Hybrid electric/hydraulic drive system

A locomotion simulator has two independently controlled movable footpads. Each footpad is positioned dynamically in three-dimensions. The top of each footpad has a controlled rotational motion, and the assembly having the two footpads is rotated under control. In operation, a user, whose feet are tracked in position and angle, walks or runs on the simulator and the footpads are controlled to simulate ground contact. Controlled rotation and translation movements permit simulation of turning, climbing, and decending.

Computer controlled robotic system for unencumbered movement

A point sampling method for improving the images produced by a computer graphics system which uses quality measures together with a hill-climbing technique to generate an optimal rook placement of sample points. Two quality measures are used, the root-mean-square (rms) transition error and the maximal circle size. To derive the optimal rook placement, points are placed initially in any rook placement, such as along the diagonal of the pixel. New rook placements are generated by interchanging the x-coordinates of any pair of points. The optimal placement is determined by in a sequence of steps. At each step, all possible pair interchanges are tested by computing the quality measure for each of the possible interchanges. After all are evaluated, the sequence is concluded by making the interchange that provided the most improvement in the quality measure. The point placement after each interchange is used as the basis for the next step in the process. Each step follows the same procedure until no interchange improves the quality measure, or until the quality measure fails to be improved by at least a predetermined small increment.

Method for point sampling in computer graphics systems

A system for simulating the forces associated with touching objects in a virtual reality simulator system includes a panel that contains an example of the various types of switches, knobs and any other item or object being simulated that is to be touched by a user of the system. The panel is attached as the payload of a robotic positioning device controlled by a computer. The computer is connected to a tracker and a flexible lightweight data glove worn by the user. The computer maintains a database that includes the positions of all of the controls being simulated by the system. The computer uses the trajectory data to determine the position of the robotic device.

Apparatus for robotic force simulation

An image generator system for producing real time imagery from a digital database includes processors performing in sequence: scene data management, geometry processing, and video processing. The scene data management processor selects and organizes the data base objects, modeled with polygons, and distributes polygons to parallel geometry processing modules. Geometry processing modules convert the images from 3-D to 2-D coordinates and divide the polygons into two-pixel-high scanline-aligned 'spans'. Spans are collected and sorted in a region buffer associated with each channel of a scene. Occlusion is done hierarchically to conserve time and bandwidth, and antialiasing is performed recursively for the same reasons.

Graphics processor for parallel processing a plurality of fields of view

A method for determining which objects are visible in each pixel of a digitally-generated image is described. The method uses comparison of distances from the viewpoint (Z-sorting) for occlusion. The number of Z comparisons required is minimized by utilizing a hierarchy of regions in the screen area, and thereby, resolving occlusion for areas larger than pixel areas where possible. Use of the area hierarchy increases the efficiency of the occlusion processing. In a preferred implementation, the screen is divided into equal-sized horizontal regions each corresponding to typically four scanlines. Polygons for each image are subdivided into pieces that correspond to the preset hierarchy of regions, and occlusion processing occurs independently in parallel for two or more regions. Each region is subdivided further into smaller regions, each level of the hierarchy having regions half the size of a higher level region. The minimum and maximum Z values of a polygon's contribution to a region are compared to previously determined values for a hierarchy of subregions. Occlusion is accomplished at the highest level of the hierarchy at which portions of the incoming polygon contribution either occlude or are occluded by previous polygons. Provisions are made for transparent and interpenetrating polygons.

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Fremont, CA, United States of America

Roy Westlake Latham