Abstract: A CAD/CAM system provides a positive indication to a user that the user has located a cursor so that an object on a two-dimensional sketcher plane has been aligned with a point of interest within three-dimensional model geometry, even though the point of interest may not be within the two-dimensional sketcher plane. The object may be snapped to a projection of the point of interest onto a corresponding location on the two-dimensional sketcher plane. Additionally, an association may be defined so that further manipulation of the point of interest on the model within three dimensions will automatically result in corresponding re-location of the object on the two-dimensional sketcher plane. Additionally, to maintain an appropriate relationship among historical data of the CAD/CAM system, interim geometry, which was generated as a result of user actions performed since the user operated on a particular sketch, is removed prior to the user subsequently operating again on the particular sketch.

Abstract: A method and apparatus that keeps information on all entities that are created when a model is built in a CAD system, including an indication of which command causes each entity to be added to or taken from the model. From this information, the system can determine the state of the model at any given time during its creation, without having to regenerate commands that generated the model at the determined state. For each new command, only those entities that are newly created are added to the database. The entities each have a version field that allows the same data to relate to different versions of the model.

Abstract: A method and apparatus for automatically trimming a geometry that is formed by the spatial intersection of geometric model primitives created on a computer aided design (CAD) system. In one embodiment of the present invention, an automatically trimmed representation of the geometry is determined while retaining the geometric model primitives used to determine the automatically trimmed representation. In another embodiment, the automatically trimmed representation is determined based upon a concept of sense that can be assigned to each model primitive, or inferred for each model primitive. In a further embodiment, the automatically trimmed representation is determined based upon a boolean evaluation of the spatial intersection of the geometric model primitives.

Abstract: The invention relates to a method and apparatus for tracking and modifying the accumulated error and the current operational tolerance of each topological entity in a geometric model of a three dimensional object. Each topological entity has assigned to it a Mintol value and a Maxtol value, Mintol represents the current accumulated error associated with the entity. Maxtol represents the operational tolerance of the entity for future operations. The Mintol value for an entity is set and occasionally adjusted so that it comprises a volume which encompasses all other entities adjacent to the particular entity. With respect to Maxtol, when two entities are within a distance from each other which is less than the sum of the Maxtols of the two entities, the two entities can be combined. Maxtol is adjusted whenever Mintol is adjusted so as to remain larger than Mintol and whenever a new entity is created by the combination of old entities, so as to encompass the Maxtols of the two old entities.

Abstract: A cursor is dynamically attached to a two-dimensional representation of a three-dimensional surface in a CAD system. The system maps input coordinates indicating an initial position and a final position of a cursor to coordinates of a u-v surface representation of a the three-dimensional surface. The u-v coordinates are then mapped to display coordinates. The option to display this cursor on the surface is made by entering a command and by selecting a surface. The cursor preferably includes vectors indicating the magnitude and direction of the slope, and the display includes a window for displaying the u-v representation of the surface. A user can pick points on the surface based on what is visually observed on the display without projecting the point to another surface.

Abstract: An information processing system performs boundary evaluation in a non-manifold environment. The system may be used for representation of objects in three dimensions, in a very general manner. Objects are represented by merging boundary representations of constituent sub objects, and selecting portions of the resulting merge boundary representation. Selection is based on criteria applied to a containment history of each portion of the merged boundary representation.A data structure suitable for boundary evaluation in a non-manifold environment includes a constructive solid geometry tree and a boundary representation. The boundary representation further includes boundary descriptions, a list of regions, containment histories of each region and a mark indicative of selection or non-selection of each region.

Abstract: A distributed data processing system includes at least a first data processing system and a second data processing system. The first data processing system includes an application that is connected by a full duplex data transfer path to a transport provider service. Transport provider service couples the first data processing system with the second data processing system. The second data processing system has a similar transport service provider. This transport service provider is coupled to a full duplex data transfer path. A full duplex data transfer path to a remote driver may be opened by the application of the first data processing system. This application may also cause various modules to be pushed on to this data transfer path.

Abstract: A method and apparatus are provided for the testing, training on, demonstration of, or otherwise exercising an integrated and interactive software system in the environment in which such a system is to be utilized. A tool used for accomplishing these objectives has a record mode in which a unified input queue (UIQ) is generated of all inputs to the system when the system is being utilized to perform an exemplary function. In play mode, the system normally operates in response to inputs from the UIQ, which inputs are provided in the same sequence and with the same duration between inputs as when recorded. Controls are provided to permit selection of application tools which are to be recorded and which are to be played back, to control portions of the operations which are to be recorded, to edit the UIQ to add, delete or change inputs, to move forward or backward by controlled amounts in the UIQ in play mode and to control the rate at which inputs are applied to the system in play mode.

Abstract: A computer implemented method for designing a form board for manufacturing a wire harness is used to convert a three dimensional computer representation of a wire harness into a two dimensional model of the harness. The method includes modelling the harness as a plurality of segments and iteratively moving each segment into an unfolding plane. A computer generated representation of the two dimensional model is provided.

Abstract: A computer aided design tool provides a user with the capability of generating a design implementation for electronic circuitry. In this system the user generates a design schematic specifying a functional description of a design for electronic circuitry without the need for specifying packaging information. The system is provided with a packaging tool for generating a physical package for the circuitry of the design schematic. Use of the packaging tool may be deferred until the design schematic has been completed and verified. Further, a user of the system has the option of specifying certain packaging information when creating the design schematic or delaying such specification until just prior to packaging of the design.

Abstract: An electromagnetic shielding clip made from a metallic strip having a U-shaped attaching portion with a notch formed on each side of the attaching portion. The metallic strip has a bent portion at the top of each side of the U-shaped attaching portion. A contact wing extends from at least one of the bent portions. The clip engages a conductive panel between the bent portion and the top ledge formed by the notch.

Abstract: A method and apparatus for improving the display of objects on an interlaced raster-scan television are disclosed. The invention takes each data point that will appear as a pixel on the screen and makes it appear also at pixel locations displaced by one unit in each of two axes, individually or collectively if desired. The direction of displacement is uniform for any given picture. The additional appearance is not stored as part of the picture data, but instead is generated "on the fly" as part of reading the data and preparing it for presentation on the television screen.

Abstract: A method and apparatus for controlling a stepper motor involves the generation of command currents which drive the stepper motor and provided critical damping of the natural resonance of the stepper motor. Digital error signals are developed by selectively combining a position signal and a digital velocity signal which is derived from a feedback signal proportional to velocity. In one embodiment, the digital error signals are converted into command currents for driving the stepper motor in such a manner as to achieve damping of the motor's natural resonance. In an anternative embodiment, the digital error signals and feed forward acceleration signals and/or feed forward velocity signals are converted into command currents for driving the stepper motor so as to achieve damping of the motor's natural resonance, as well as correction for positional errors induced by either velocity or acceleration.

Abstract: A projection aligner is provided wherein anamorphic metric distortion can be introduced in the projection image by employing a bending mirror that makes a slight change in magnification along one axis of the image. In one embodiment of the invention a pneumatic bending mechanism is employed and in another embodiment, a mechanical system is employed.

Abstract: A projection aligner is provided wherein the image position can be shifted by employing a bending mirror which makes a slight change in the magnification.

Abstract: A method and apparatus for targetless X, Y and .theta. alignment of a semiconductor wafer having thereon a large number of identical microcircuits or dies that are arranged in a pattern to form rows and columns separated by scribe lines or "streets." The orientation of the wafer is defined by the location of the wafer flat. Each one of the scribe lines or "streets" has a known angular relationship with the wafer flat. The alignment method and apparatus utilizes the wafer "street" pattern for identification instead of special targets located on the wafer. Coarse alignment of the wafer is achieved by locating the wafer flat and then rotating the wafer into approximately correct orientation. Fine alignment of the wafer is performed by opto-electrically locating the edge of a "street" and then rotating the wafer until the "street" edge is parallel to either the X or Y principal axis.

Abstract: A method and apparatus are disclosed for fine aligning a photomask to a semiconductor using the interference and diffraction effects produced by coherent light impinging upon or passing through repetitive patterns on a photomask and a semiconductor. A plurality of photodetectors are employed to convert the interference information into phase dependent electrical signals that are used to control conventional X, Y and .theta. workpiece positioning mechanisms.

Abstract: A lamp holder that compensates for thermally induced expansion of an arcuate lamp is disclosed. Each end of the arcuate lamp is secured to a relatively flexable lamp support. In the preferred embodiment the lamp support at one end is moveable generally in a plane containing the arcuate lamp, while the lamp support at the other end is moveable generally in a plane that intersects the plane of the lamp. The resulting horizontal and vertical freedom of movement compensates for thermal expansion of the lamp during lamp operation. Both lamp supports are mounted on a lamp holder base, having a plurality of locator pin apertures therein that are cooperatively operative with locator pins positioned on the base of a lamp holder housing. The locator pins and locator pin apertures accurately position the arcuate lamp with respect to an optical system. Forced fluid cooling of the lamp is provided through the lamp holder housing.

Abstract: A non-contacting, non-clogging, electro-mechanically operated marking device or inker for continuous or intermittently marking a semiconductor wafer die is disclosed together with a method of operating the device. The marking device has an ambient pressure ink reservoir within which is mounted a thin, capillary filament guide tube. A length of filament such as, fishline, is positioned within the tube and secured at one end to the plunger of a solenoid. The distal end of the filament is driven out of the capillary tube by the solenoid to force a small amount of the marking fluid or ink out of the reservoir and onto the die without the filament contacting the die. The solenoid coil is energized by a current pulse having a first current level and a second current level that is less than the first current level. The second current level provides a short holding current for the solenoid to prevent spattering of the marking fluid.

Abstract: A method and apparatus for damping stepper motors are disclosed. A tachometer feedback is used to modulate the phase angle of the stepper motor command currents to achieve damping.