Gerald M. Radack

Jigsaw puzzle matching using a boundary-centered polar encoding☆

Abstract A shape representation suitable for efficient matching (fitting together) of parts of boundaries of two-dimensional objects is described. This representation, which uses polar coordinate systems centered around curvature maxima and minima, is applied to the problem of fitting together curved jigsaw puzzle pieces. A program implementing these techniques is described.

Automatic inspection planning within a feature-based CAD system

Abstract This paper describe a CIM system which incorporates automatic generation of inspection on plans for coordinate measuring machines (CMMs). Design is done in terms of form features. Associated with each feature are inspection plan fragments (IPFs) which are instances of inspection procedures. There are three basic types of plan fragments for CMMs: (1) fragments for checking the internal dimensions of a feature, (2) fragments for checking the relationships between features, and (3) modified fragments for use when the feature to be inspected intersects another feature. Using this approach, a list of suitable inspection points and approach vectors is generated. A path planner then combines the elements of the list to produce a valid inspection path for the CMM. The system is consistent with the accepted ANSI Y14.5M standard for dimensioning and tolerancing as well as with observed industrial practice.

Positioning and animating human figures in a task-oriented environment

TEMPUS is an interactive graphics system which enables a user to model the task-oriented activities of several human agents in a three-dimensional environment. The user can create one or more human figures which are correctly scaled according to a specific population, or which meet certain size constraints. These figures may be viewed in any of several graphical modes.

The integration of inspection into the CIM environment

The authors describe a CIM (computer-integrated manufacturing) system that combines inspection specification and planning with the design process. A part is described in terms of generic features: form features (e.g. pockets or ribs) and inspection and tolerance features (e.g. callouts). Rules for inspection are incorporated as part of the generic features. Part definitions and data structures necessary to describe the design are discussed. An overall design consists of a set of feature instances and their relations. Individual features can be automatically checked as they are specified by the designer for overt errors (e.g. incomplete information such as an undefined datum). The overall design is then evaluated for correctness of geometry and inspection specifications. In particular, the designers tolerance specifications are checked for completeness and internal consistency. Once a design is complete, a module generates process and inspection plans by concatenating the processing and inspection rules associated with individual features and optimizing the result with respect to the overall cost of inspection. An implementation is described.<<ETX>>

Incorporating knowledge of geometric dimensioning and tolerancing into a feature-based CAD system

A system is described which aids a designer in assigning dimensions and tolerances to designs of mechanical parts. The system is constructed using an object-oriented approach. Designs are created using geometric features such as slots and holes. For each feature, there is knowledge about the object regarding appropriate ways to dimension and tolerance that feature. The tolerancing system used is unambiguous and is similar to geometric dimensioning and tolerancing (GD&T), the standard system used in industrial practice.<<ETX>>

Akrti: a system for drawing data structure

A system for graphically displaying data structures created by programs during execution is described. Each built-in data type is displayed in a standard way. No additional programming on the part of the user is required to use the system. Special hints may be used, at run time, to declare record/point data structures as abstract data types (e.g. binary tree, linked list, stack, etc.). The drawing system uses these hints to invoke built-in algorithms to draw each abstract data type. If a record/point data structure does not fit into one of the special types, then it will be drawn as a graph. Picture attributes such as colors, orientation, and spacing can be changed by the user. Output can be displayed on either traditional terminals or through a window system.<<ETX>>

Generating Polytope Intersection Configurations from a Symbolic Description Using CLP(ℜ)

Given two polytopes whose coordinates are not known, and a list Iof pairs of edges from the two polytopes which intersect, we wish to place the vertices on the plane (i.e., assign coordinates to the vertices) in a way which is consistent with I. Elements of Idistinguish between intersections that occur at vertices or at interior points of edges (i.e., points which are not vertices), but do not give either the absolute or relative position of an intersection. In addition to being consistent with I, a placement should satisfy certain aesthetic rules; e.g., a placement should make the polytopes appear regular rather than oddly-shaped when possible. This problem is treated as a constraint satisfaction problem. A set of arithmetic constraints on the coordinates of the vertices as well as certain auxilliary variables is generated. A search method is then used to find a solution to these constraints. This system is implemented in CLP(ℜ) and makes use of CLP(ℜ)’ s built-in constraint solution facilities where possible.