ABSOLUTE COORDINATES

The location of a point in terms of distances and/or angles from a fixed origin.

ACCESS TIME

The time it takes to transfer an instruction or unit of data from computer memory to the processing unit of a computer. The time it takes to get a unit of data from a direct access storage device to computer memory.

ACCURACY SETTING

Refers to system tolerances. All 3D objects, whether manufactured or computer-generated, are defined within acceptable geometric tolerances.

ACTIVE COORDINATE SYSTEM

Coordinate system in which key-in point coordinates and read-out coordinates are expressed.

ACTIVE DEPTH

Plane in a 3D design upon which you can place elements and perform manipulations.

ADDRESS

The coded representation of a specific computer workstation or host computer used in transferring data through a network. A unique number is assigned to each computer.

ALIASING

Refers to the jagged lines or edges that can appear in computer-drawn images. Aliasing occurs when smooth lines or edges in an image are drawn with pixels. Aliasing can be eliminated automatically through a technique called oversampling (also called ANTIALIASING), but at a cost of increasing the time required to create the image.

ALGORITHM

Mathematical formula or procedure.

AMBIENT LIGHT

Background light that is defined in rendered images or animations.

ANALYSIS

The field of mathematics that is most closely tied to applications, used to understand the process of change and movement of a part in time and space. In CAD, analysis refers to any portion of the process for design optimization.

ANNOTATION

The process of inserting text or a special note, explanation or to provide relevant detail on a CAD/CAM drawing.

ANSI (AMERICAN NATIONAL STANDARDS INSTITUTE)

The American National Standards Institute (ANSI) is a privately funded, non-profit organization which coordinates the development of voluntary standards in the United States and is the agency that approves standards (as American National Standards). It coordinates and manages U.S. participation in the work of several non-governmental international standards organizations, including ISO and IEC (NCGA). ANSI's membership consists of over 1000 companies and organizations.

APERTURE CARD

A film media used to store reduced images of engineering documents. The film is mounted on card stock and often has associated hollerith data.

APPLICATION PROFILE

A number of application protocols required for a specified task or industry sector. Associated with STEP.

APPLICATION PROTOCOL (AP)

Defines the context for the use of product data and specifies the use of the standard in that context to satisfy an industrial need. Associated with STEP.

API (APPLICATION PROGRAMMING INTERFACE)

Provides standard documented access to software functions, allowing customers and third parties to develop and customize their own commercial applications.

APT (AUTOMATICALLY PROGRAMMED TOOLS)

Acronym for "Automatically Programmed Tools." One of the principal software languages used in computer-aided manufacturing to program numerical control machine tools. APT is an English-like language for describing operations of NC machines.

ANTISYMMETRY SURFACE RESTRAINT

The restraint of a surface tangent to the surface. This implies that the structure is symmetrical about this plane, and the load on the implied symmetrical part is equal to, but in a direction opposite to, the modeled part.

ARC

A curve segment defined by a start angle, end angle, and a constant radius.

ARCHIE

A system for locating files that are stored on FTP file servers.

ARCHITECTURE

The overall design basis for a product, subsystem or system. The architecture defines the rules, structure and capabilities of the item.

ARCHIVE

The storage area where engineering information is received, organized, stored and distributed to users. The primary emphasis of the engineering archive is to protect and preserve engineering information for its users and owners.

ARRAY

A rectangular or circular pattern of graphical objects.

ASCII (AMERICAN STANDARD CODE FOR INFORMATION INTERCHANGE)

An industry standard character code that is widely used for information interchange among data processing systems, communications systems, and associated equipment.

ASPECT RATIO

The shape of the display device on which an image will be viewed. The aspect ratio of a rendered image is expressed as the width of the image divided by its height.

ASSEMBLY

A final gathering of piece-parts and subassemblies to make one unique assembled product.

ASSEMBLY DRAWING

A drawing which can be created on the CAD system to represent a major subdivision of the product, or the complete product.

ASSEMBLY MODELING

The process by which individual solid models are brought together to form an assembly model.

ASSOCIATIVE GEOMETRY

A system that lets you place graphic elements based on a relationship (for example, parallel to) with existing graphic elements. Elements placed associatively maintain the relationship when the existing graphic element is manipulated.

ASSOCIATIVITY

Operating under a single integrated database structure, allows engineers to make changes in any application (i.e., design, drawing, manufacturing, assembly, mold, cabling, etc.), have those changes reflected instantly throughout all applications as well as in every deliverable (including drawings, bill-of- materials, NC tool paths, etc.), and vice versa. Full Associativity means "A change made anywhere is reflected everywhere."

ATTRIBUTE

A unique property of a display element, picture, or network. The key words placed in an index to facilitate organization and management. Examples include a document number, creation dates and originator. This information is then used to query and retrieve a document from the system

AUTOMATIC DIMENSIONING

A CAD capability that will automatically compute and insert the dimensions of a design or drawing, or designated section of it.

AXIS

An annotation tool that provides a model's orientation in 3D space.

AXIS [TOOL]

A general direction of relative motion between a cutting tool and the workpiece. A basic concept in NC machining.

AXISYMMETRIC

A solid geometric entity that is symmetric and typically revolved about a common axis.

B-SPLINE (BI-CUBIC SPLINE)

A sequence of parametric polynomial curves (typically quadratic or cubic polynomials) forming a smooth fit between a sequence of points in 3D space. The piece-wise defined curve maintains a level of mathematical continuity that is dependent upon the polynomial degree that is chosen. B-splines are used extensively in the mechanical design applications in the automotive and aerospace industries.

BACKBONE

A central high speed network that connects smaller, independent networks.

BACK TURNING

Turning operation where the tool moves from the spindle end of the cut toward the tail stock as opposed to from the tail toward the spindle.

BALL END MILL

Milling tool commonly used for creating complex surface machining operations. End of tool is rounded so that the radius on tool end equals half of tool diameter.

BAUD

A measurement of signaling speed of a data transmission device Baud rate does not equal bits per second.

BENCHMARK

The program(s) used to test, compare, and evaluate in real time the performance of various CAD/CAM systems prior to selection and purchase.

BETA SITE

A user's CAD/CAM site or facility selected by mutual agreement between the user and his vendor for testing out a new system, application package, or hardware or software enhancement before its sale to other customers of the vendor.

BEZIER CURVES

A quadratic (or greater) polynomial for describing complex curves and surfaces.

BILL OF MATERIALS

Manufacturing data referencing to parts and materials listing use, frequency of use, and structure.

BITMAP

A matrix of pixels representing an image. Each pixel location has a unique memory location in the computer, allowing efficient localized image processing.

BI-DIRECTIONAL ASSOCIATIVITY

The associative relationship between a 2D drawing and a 3D model. The associativity is where both the drawing and the model can update each other.

BOOLEAN OPERATION

Algebraic or symbolic logic formulas (adapted from George Boole's work) used in CAD to expand design-rules checking programs and to expedite the construction of geometric figures.

BOOLEAN SEARCH

A database search for combined attributes implied by linguistic operators AND, OR and NOT.

BORING

Drilling operation performed on either a milling machine or a lathe used for large diameter holes.

BOUNDARY

A 3D outline of a data volume.

BOUNDARY EVALUATION

An operation that generates a B-Rep solid from a CGS solid.

B-REP (BOUNDARY REPRESENTATION)

A database method that defines and stores a solid as a set of vertices , edges, and faces (points, lines, curves and surfaces) which completely enclose its volume.

BOUNDED OBJECTS

In solid modeling, an object is considered bounded if it has a complete set of bounding surfaces and is restricted to occupying a finite volume.

BOX

A solid primitive defined as a right-rectangular hexahedron. That is, it has six rectangular faces. The typical input required is length, width, height, and location.

BRIDGE

A device that filters or passes traffic, based solely on the destination network address.

BROACHING

Cut sizing operation where non-rotating tool is forced through cut to create exact sizing and/or surface finish.

BROWSER

Client-software that lets users read or scan documents on the World Wide Web.

BUS

In computer hardware, a circuit or group of circuits providing a communications path between two or more devices, such as between a CPU, peripherals, and memory, or between functions on a single PC board.

CACHE

An area on a magnetic disk used for temporary storage. Cache is used to optimize operation and retrieval speeds.

CAD (COMPUTER AIDED DESIGN)

The use of computer and digital technology to support the preparation of engineering designs, typically limited to geometry only.

CAE (COMPUTER AIDED ENGINEERING)

The use of computer and digital technology to support basic error-checking, analysis, optimization, manufacturability, etc., of a product design. Finite Element Analysis (FEA) is one example of CAE.

CAM (COMPUTER AIDED MANUFACTURING)

The use of computer and digital technology to support the fabrication of a product. Examples of CAM include numerical controls machine programming, computer-aided process planning, and robotics.

CAD/CAM (COMPUTER-AIDED DESIGN / COMPUTER-AIDED MANUFACTURING)

The integrated use of computer and digital technology to support the entire design-to-fabrication cycle of a product.

CALS (COMMERCE AT LIGHT SPEED)

A Department of Defense initiative that calls for all documentation, including engineering drawings, to be submitted to the DoD electronically. A strategy to further enterprise integration through the streamlining of business processes and the application of standards and technologies for the development, management, exchange, and use of business and technical information. The initiative includes technical publications and both raster and vector data. The acronym was previously defined as Continuous Acquisition and Lifecycle Support and before that Computer-Aided Acquisition and Logistic Support.

CASE (COMPUTER-AIDED SOFTWARE ENGINEERING)

An umbrella term for a collection of tools and techniques which are said by their distributors to promise revolutionary gains in analyst and programmer productivity. The two prominent delivered technologies are application generators and PC-based workstations that provide graphics-oriented automation of the front end of the development process

"CANNED" CYCLE

Term commonly used to refer to pre-programmed machining cycles on a particular machine tool. Examples include drilling, boring, and tapping.

CAPTURE

A process required to convert hardcopy information into usable raster images through raster scanning, QC and cleanup.

CARTESIAN COORDINATE SYSTEM

A rectangular coordinate system consisting of three mutually perpendicular axes: the x axis, the y axis, and the z axis.

CATALOGS

Catalogs are on-line, organized tables of information (e.g., standards, parts, and tooling). Catalogs can be industry specifications such as the American Institute of Steel Construction Catalog, or company specified, such as a catalog of mold bases available from a vendor.

CD-ROM (COMPACT DISC - READ ONLY MEMORY)

A computer readable version of the familiar digital audio compact disc. The CD-ROM can store text, sounds and images, as well as video information.

CHAMFER

A beveled edge or corner between two otherwise intersecting lines or surfaces.

CHANGE PROPAGATION

The change made to a part's design as it is refined into a product, and as current products are evolved into new products. Also refers to the distribution of change from a root cause.

CHILDREN

(1) The components of a design instance in a product structure tree. Also referred to as parts. (2) Nodes in a database tree structure that have a parent.

CHIPS

Term referring to the "chips" of material removed by a cutting tool.

CIM (COMPUTER-INTEGRATE MANUFACTURING)

Automated use of computer and digital technology to completely integrate all manufacturing process with engineering design.

CIRCLE

Element that is a closed planar curve, every point of which is equidistant from the center.

CIRCULAR INTERPOLATION

Method of instructing a machine tool to follow a circular path. Used instead of programming many straight line moves around the arc.

CLEAN MODELING

Refers to the practice of removing geometry from a model that is not wanted or needed. Also refers to the use of proper geometry construction techniques, such as creating continuous surfaces, minimizing narrow faces, and avoiding small corner angles, that facilitates downstream processes.

CL FILE (CUTTER LOCATION FILE)

A file of data generated from a machine tool path created on a CAD/CAM system or on an APT processor. The CL file contains X, Y, and Z coordinates and other NC information to be post-processed to program NC machines.

CLIENT/SERVER

Any application in which the requester of action is on one system and the supplier of action is potentially on another. The goal is to distribute processing across a network between the desktop and a server, reducing network traffic and preventing the desktop and server computer from getting overloaded.

CLIMB CUT

Type of milling where cutting forces are directed down into the workpiece. Opposite of conventional cutting. Determined by combination of spindle rotation direction and tool feed direction.

CMM (COORDINATE MEASURING MACHINE)

Equipment used to inspect part dimensions

CMS (LIFE-CYCLE MANAGEMENT SYSTEM)

A set of processes (which may include computer-aided software engineering tools) which facilitate the creation, tailoring, and navigation of a system development life cycle. A life cycle management system may take the form of an integrated project support environment or an estimating system linked to a project scheduling and tracking system.

CNC (COMPUTERIZED NUMERICAL CONTROL)

A numerical control system where a dedicated computer is used to perform the basic numerical control functions controlling the movement of a machine tool under the direction of a control program stored in the memory of the computer.

COINCIDENCE

Refers to geometry that occupies the same spatial location. For example, coincident vertices are points that occupy the same x,y,z coordinates. Coincident lines can have differing lengths while one occupies the same locations the other.

COM

Computer Output Microfilm (COM) is microforms containing data produced by a recorder from computer-generated electrical signals.

COMMUNICATION PROTOCOL

A standard, specified software interface for communication between computers.

COMPATIBILITY

The ability of a particular software program to be used without prior modification or special interfaces.

COMPILER

A computer program that converts or translates a high-level, user-written language into a language that a computer can understand. Typically one to many (i.e., one user instruction to many machine-executable instructions).

COMPOSITES

Parts fabricated using cloth soaked in epoxy resin. There are three common methods for building composite parts. Large panels, similar to sheet metal parts, can be made by layering sheets of epoxy-coated composite material (fiberglass, graphite fiber, etc.) on top of each other, and then curing them in an oven. Typical applications for this method include aircraft and automotive body panels. A second method involves wrapping long strands of composite material tape around a mandrel; it is commonly used to build tube-shaped parts and pressure vessels. A third approach involves mixing chopped fibers of a composite material in with epoxy resin and "molding " parts; it is used for building more solid-like geometry, similar to castings, forgings and machined parts.

COMPRESSION

Process of compacting digital data, images and text. Software algorithms search the raster image to build a greatly condensed (from a file storage perspective) format of the image. In the case of CCITT Group IV, the file size reduction is about 25:1. The actual compression factor is greatly dependent upon the quality of the scan and upon the density of the information.

CONCENTRIC

Having a common center or origin point with varying radii.

CE (CONCURRENT ENGINEERING)

A systematic approach to creating a product design that considers all elements of the product life cycle from conception of the design to disposal of the product, and in so doing defines the product, its manufacturing processes, and all other required life cycle processes such as logistic support.

CONFIGURATION

A particular combination of a computer, software and hardware modules, and peripherals at a single installation and interconnected in such a way as to support certain.

CONFIGURATION MANAGEMENT (CM)

Controls and manages product description with its supporting technical and scientific information.

CONIC

Element having the form of a cone.

CONIC SECTION

Curve formed by the intersection of a plane with a cone.

CONVERSION

A change of formats, such as hardcopy to raster, raster to vector, vector to vector, vector to raster and raster to hardcopy. Conversion also implies the translation of information from one type or form of media to another, such as tape to disk or magnetic to optical.

CONTOURING

A numerical control method where the control program generates a contour by keeping the cutting tool in constant contact with the workpiece.

CONTROLLER

Device attached to a machine tool which reads and stores machine data file and passes movement information to the machine tool. Also controls other machine activities such as turning coolant on or off.

CONVENTIONAL CUT

See Climb Cut above.

CONVERGENCE

The closeness of the approximate finite element analysis results to the actual solution.

COOLANT

Fluid applied to a cutting operation to cool and lubricate the workpiece and the tool.

COONS PATCH

Surface defined by four boundary curves, tangents, corner twists, and blending functions. Curvature and continuity can be maintained between patches.

COORDINATE FRAME

The origin location of a cartesian coordinate system and the orientation of its axes.

COORDINATE SYSTEM

Geometric relation used to denote the location of points in 3D space. The most common is the rectangular coordinate system, whereby points are located by traversing the x,y and z axes of 3D space. Normally, the origin of a coordinate system is defined as 0,0,0 though this is not required. Other coordinate systems are used to more easily express the coordinates of specific geometric entities.

COORDINATES

Ordered set of absolute or relative data valves that specify a location in a coordinate system.

COPLANAR

Refers to two or more entities that lie on the same plane. Two planar surfaces , for example, that lie on the same 3D plane are considered coplanar. If these coplanar surfaces share a common edge, it is recommended that they be joined into a single surface.

CORRUPTION

A condition in which model files or the modeling code itself becomes unusable. Corruption can occur from various causes, most of which are internal system conflicts.

CPU (CENTRAL PROCESSING UNIT)

It is responsible for arithmetic computations, logic operations, memory addresses, and data and control signal traffic in a computer.

CROSS SECTION

View of the interior of an element as it is sliced along a plane.

CSG (CONSTRUCTIVE SOLIDS GEOMETRY)

A scheme for representing solid objects. It is a tree representing instances of solids and combination operations (union, intersection, difference).

CT (COMPUTER TOMOGRAPHY)

An object is scanned by shooting a tightly focused beam of low intensity X-Rays through it from the source and sensing the strength of the remainder beam after it goes through the object. The whole contraption then rotates a little bit (say, one degree) and the process repeats. Once the scanner collects a bunch of these readings a computer munches on them and eventually it spits out a graphical representation of the "slice". The object is then moved up a little bit (say, one centimeter) and the whole thing starts all over again. Once the procedure is done and all the slices have been computed, you have a stack of slices that can be used to "view" the insides of people without ever invading their bodies ('cept for the radiation, of course - but even that represents a much lower dose than is normally dispensed via traditional X-ray procedures.

CURVE

A line that changes direction in a smooth, continuous fashion.

CURVE FITTING

The process of passing arc segments through a number of control points to create a curve.

CURVE SMOOTHING

The process of curve or surface approximation using polynomial equations to generate a curve that passes near, but always through, a set of control points or mesh vertices.

CUSP

Point or edge in a curve or surface.

CUTCOM (CUTTER COMPENSATION)

A method by which a machine tool compensates for a difference between the size of the actual tool loaded in the machine and the programmed tool size.

CUTTER PATH

The path of a cutting tool through a part. The optimal cutter path can be defined automatically by a CAD/CAM system and formatted into a numerical control (NC) tape to guide the tool.

CUTTING PLANE

A tool that slices through the 3D data exhibiting characteristics of a plane in the data, including scalar and vector measurements.

CYLINDER

A solid primitive defined as a right-circular cylinder. The ends are circular and of equal radius. The axis is normal to the ends.

DATA

Information used as a basis for reasoning or calculations.

DATA SET

A computerized collection of data items that can be processed to analyze or visualize relevant information.

DATABASE

A collection of data fundamental to an enterprise. The collection is organized in a logical structure for the primary purpose of automating information for image retrieval.

DATUM

Point or plane of reference.

DATA MANAGEMENT

Coordinated management of all aspects of electronic manipulation of machine-readable data in a computer environment; includes data capture, communication, storage, retrieval and associated processing.

DBMS (DATABASE MANAGEMENT SYSTEM)

Software designed to manipulate the information in a database. It can create, sort, display selected information, search for specific information, and perform many other tasks of a database. This kind of software allows speed of access and the ability to automatically produce reports.

DATA MANAGEMENT STANDARDS

Provide common definitions of the data elements, their attributes, relationships, data integrity constraints, and database access rules. This includes standards for system and data protection and security.

DATA MODEL

The logical data structure developed during the logical database design process is a data model or entity model. It is also a description of the structural properties that define all entries represented in a database and all the relationships that exist among them.

DATA MODELING

A structured method for representing and describing the data used in a business function automated system. Data modeling is used in combination with two other structured methods, data flow analysis and functional decomposition, to define the high-level structure of business and information systems. Its primary function is to define the attributes of and relationships among data items.

DECOMPRESSION

Process of returning a compressed file to its full bitmap.

DEDICATED

Process or system that is available for only one function or use.

DESIGN OPTIMIZATION

This is the capability, in virtual prototyping software, to define design objectives, constraints, and variables, and then have the software iterate automatically to the optimally-performing configuration.

DESIGN OF EXPERIMENTS (DOE)

DOE is a complementary technique to design optimization. DOE is a methodology for running a statistically significant battery of tests (or computer simulations) on a design to determine its sensitivity or robustness to design or manufacturing variations. Applied with virtual prototyping, DOE automatically produces the arrays of simulation permutations required for a complete "experiment." By thus submitting new design variations to a consistent, standard battery of "virtual tests," manufacturers can develop sufficiently rigorous knowledge of, and confidence in, the performance of their system designs to avoid all but a single, perfunctory physical prototype.

DESIGN STUDY

This term describes the ability in virtual prototyping software to select a design variable (say, the length of a link in a mechanical system design), sweep that variable through a range of values, and then simulate the motion behavior of the various designs in order to understand the sensitivity of the overall system to these design variations.

DESKEW

Process used to remove skew or distortion through a small angle rotation.

DESTINATION SYSTEM

The computer hardware, software, and network receiving transferred data.

DETAIL DRAWING

The drawing of a single object design including graphics, dimensions, and annotations, complete enough for manufacturing.

DIGITAL TECHNICAL DATA

Includes the part descriptions, product specifications, and standards that the initial designer draws upon; the engineering drawings and product data used in design and manufacturing; the information needed to guide the people who operate the system in the field, or who support and maintain it at all echelons of the logistic support structure; the materials needed to train new operators, maintainers and other technicians; and the information needed for re-procurement, re- manufacturing, modification, and feedback to industry for future design.

DMIS (DIMENSION MEASURING INTERFACE SPECIFICATION)

Standard programming language of CMM machines.

DOCUMENT AUTOMATION

The process of capturing and controlling information in an electronic form. New procedures for performing tasks electronically are introduced and implemented.

DOCUMENT MANAGEMENT

The process of controlling information for later retrieval.

DOCUMENTATION

A generic term for a wide variety of hard-copy or on-line reports, drawings, and lists to be used by various departments involved in any aspect of design to fabrication of a part.

DOMAIN NAME SYSTEM (DNS)

A scheme for translating numeric Internet addresses into strings of word segments denoting user names and locations.

DOUBLE PRECISION

Numbers are stored using two computer words, providing twice as many digits as single precision. Computational round-off errors are reduced in this way.

DOWNSTREAM PROCESS

All subsequent operations or processes performed on or with a solid model. Downstream processes include (but are not limited to) analysis, NC code generation, and rapid prototyping.

DOD

Acronym for the Department of Defense.

DOS (DISK OPERATING SYSTEM)

Operating system for IBM PCs. Written by Microsoft.

DPI (DOTS PER INCH)

A measure of resolution where dots are equated to pixels.

DOT PITCH

Dot pitch is the space between pixels. The smaller the number, the sharper the image will appear.

DRAGGING

Dynamically moving the virtual image of graphical entity across the display screen to a new location using a puck, mouse, or stylus.

DRAW SPACE

As opposed to model space, an auxiliary electronic space that is defined in terms of two-dimensional coordinates where 2D text and conventional details and constructed.

DRAWING

An engineering document or digital data file(s) that discloses (directly or by reference), by means of graphic or textual presentations, or a combination of both, the physical and functional requirements of an item.

DRAWING CONVERSION

The process of moving engineering data from hardcopy or raster format to CAD format.

DXF (DATA EXCHANGE FORMAT)

A translation format to transfer geometry data to and from AutoCAD.

DYNAMICS

Refers to the study of multibody systems (mechanisms, linkages, or other mechanical systems or subsystems) undergoing large-displacement motion, taking into account the effects of applied and inertial forces.

EDGE

A bounded line or curve that forms the intersection of two faces on the surface of an object.

ELECTRONIC DOCUMENT MANAGEMENT SYSTEM

A computer system which has been designed to execute a combination of automated and operator-invoked processes that allow the capture, storage, retrieval, display, routing and maintenance of information comprising electronically stored documents.

ELEMENT

In modeling, the basic building block used in geometric modeling. Every modeled object created is assembled from elements. Elements include points, lines, curves, surfaces, solids, etc. In analysis, the lowest form of entity analyzed. In FEA this could be a mesh element. In kinematics this could be a single rigid body.

E-MAIL

Electronic messages sent and received by computer. Very fast, reliable and cheap compared to fax and traditional mail. The cost is only that of a local telephone call, regardless of distance.

EMULATE

The use of software to allow one device to imitate another.

END MILL

Milling tool that comes in several varieties including flat, corner radius, and ball.

ENDPOINT

Data point that defines the end of a linear element.

ENCRYPTION

A method of ensuring data secrecy. The message is coded using a key available only to the sender and the receiver. The coded message is sent to the receiver and then decoded upon receipt.

ENGINEERING DATA

Any technical data (whether prepared by the Government, contractor, or vendor) relating to the specification, design, analysis, manufacture, acquisition, test, inspection or maintenance of items or services. Engineering data is comprised of all information that contains authoritative engineering definition or guidance on material, constituent items, equipment or systems practices, engineering

methods, and processes.

ENTITY

Anything which is being displayed on an interactive CRT which can be identified as a discrete "thing". Entities can consist of geometry (points, lines, circular arcs, conics, splines, surfaces, solids, etc.), or as text items (notes, dimensions, lists, tables, etc.), or as "information-adding" things (coordinate systems, surface normal vectors, etc.). Menus, icons, prompts, tutorials, etc., are usually not considered entities.

EPD (ELECTRONIC PRODUCT DEFINITION)

To concurrently create, manage, share, and reuse electronic product information in a collaborative environment throughout a product's life cycle and across a distributed value chain.

ETHERNET

Xerox trademark name for a network cable system that allows communication between the workstations and servers connected to the network.

EVALUATED REPRESENTATION

A solid model that has all face, edge, and vertex information explicitly represented.

EXPLICITLY DEFINED

Information that is directly represented (rather than implied). In solid modeling, for example, an edge directly defined by an equation and two endpoints is explicitly defined.

EXPORT

Sending a scene or model to a file (IGES, DXF, STEP, TIFF, etc.) so that it can be read or imported into another program.

EXTRACT

To separate a part from the whole, to copy part of a surface without necessarily changing the location, thus creating a new element.

EXTRUSION

A process used in geometric modeling to convert 2D shapes into 3D shapes. A 3D object is created by displacing a copy of the 2D shape, than linking the copy to the original to form a closed, solid object. Examples of extrusion are a cylinder and a prism.

FACE

A type of element used in geometric modeling. A face can be a flat, planar polygon or a curved, bounded surface. Some systems define a face as the bounded portion of an infinite surface region.

FACE MILL

Milling tool used for facing a piece of stock.

FAMILY OF PARTS

A collection of parts with similar shape, but differing in physical measurement.

FAMILY OF PARTS PROGRAMMING

An efficient means of creating new parts on the system. Instead of starting from scratch, the designer makes slight changes in the design of existing parts, or uses identical parts, subassemblies, or structures designed earlier. Once the desired parameters are specified to a family-of-parts program, the system generates the new part.

FANUC

Machine controller manufactured by GE.

FCIM (FLEXIBLE COMPUTER INTEGRATED MANUFACTURING )

The integration of equipment, software, communication, human resources, and business practices within an enterprise to rapidly manufacture, repair, and deliver items on demand with continuous improvements in the processes. The FCIM initiative is a Joint Service and Agency effort to establish and implement the procedures and processes needed to expand the use of flexible manufacturing technology within the Department of Defense. The Joint Logistics Commanders chartered the Joint Technical Coordinating Group on FCIM (JTCG-FCIM) with the mission to coordinate participation of the Service Logistics Commands in the development and implementation of FCIM throughout the DoD.

FEATURED-BASED MODELING

Performs functions that were previously performed using primitive boolean operations. Example, the through-hole feature understands the rule that it must pass completely through the part and will do so no matter how the part changes.

FEATURES

Entities that encapsulate how geometry looks and how geometry behaves using rules and attributes along with their defining constraints and geometry. Features impact not only geometry to a design but a set of associative, nongeometric attributes which aid in communicating the design to the manufacturing process. Features include holes, slots, ribs, webs, and user-defined features.

FEED RATE

Refers to the traversal speed of the machine tool.

FILE

A digital repository of organized information consisting of records, items or arrays, and data elements.

FILE FORMAT

The specific organization of data within a file. There are multiple raster and vector file formats, including TIFF, IOCA, STEP, IGES and DXF. Some file formats have been specified for file interchange to facilitate data storage.

FILE NAME

User-defined name given to an interactively create file. The name should be relevant to the contents of the file.

FILE SERVER

In local area networks, allows users to share and thereby conserve the cost of peripherals (printers, modems, scanners) and software. The file server is a device on the LAN where shared software is stored.

FTP (FILE TRANSFER PROTOCOL)

A way of transferring files between computers. A protocol that describes file transfers between a host and a remote computer. It is also used to program based on this protocol.

FILLET

Rounded corner of arc that blends together two intersecting curves or lines.

FILLET SURFACE

The transition surface which blends together two surfaces, for example an airplane wing and the plane's body.

FINISHING

Operation used for final finishing of a part. Removes any remaining stock and creates the desired surface finish.

FEA (FINITE ELEMENT ANALYSIS)

A method used in CAD for determining the structural integrity of a mechanical part or physical construction under design by mathematical simulation of the part and its loading conditions. See Finite element modeling (FEM).

FEM (FINITE ELEMENT MODELING)

The process of using a mathematical model of a continuous object to divide the object into an array of discrete elements for structural analysis.

FIREWALL

A computer system that sits between the Internet and a company's LAN. It is a means of automatically limiting what a company's computer system will pass along to outside computer systems. It acts as an active gateway to keep non-company entities from accessing company confidential data.

FIXTURE

Part of assembly of parts used to hold and position the workpiece for the manufacturing operation.

FLAME CUTTING

The process of cutting two-dimensional shapes from raw material using oxy- acetylene torches controlled by NC positioning equipment.

FLAT PATTERN

The shape of the cloth ply or stock when it is cut from a flat sheet of material.

FLAVORING

The process of improving CAD/CAM data exchange results by modifying entities during an IGES data transfer.

FLEXIBLE-BODY DYNAMICS

Flexible-body dynamics is the study of the motion behavior of mechanical systems in which some

of the components are flexible.

FORM FEATURES

In solid modeling, parts of solids objects that can be specified in familiar engineering terms (e.g., fillets, slots, and through-holes).

FORMULA-DEFINED SHAPES

Shapes that are defined by using one or more equations. This includes complex shapes such as aesthetic bottles or simple shapes such hyperbolic paraboloids, oblate spheroids, prolate spheroids, or ellipsoids.

FORTRAN

An acronym for FORmula TRANslation. A high-level mathematical source language developed for scientific and engineering applications.

FREE-FORM GEOMETRY

Geometry that uses curves and surfaces to define objects.

FREE-FORM SURFACE

Surfaces that are not limited to mathematically simple linear or quadric surfaces.

FRUSTRUM

A solid primitive defined as the portion of a solid contained between two planes which are usually parallel.

FUNCTIONALITY

Refers to a set of system capabilities in terms of what functions they provide.

G CODE

A type of code used to communicate with the machine controller. These codes are contained in the post-processor output file.

GAP TOLERANCE

The allowable distance or gap between the edges of mating surface regions. A tighter (lower) gap tolerance will result in fewer and narrower gaps, but at the expense of increased processing times.

GATEWAY

A device used to connect networks with radically different communications architectures.

GEOMETRY

Elements that make up a model, such as points, lines, surfaces, solids, etc.

GENERATIVE PROCESS PLANNING

Computer-based process planning method whereby new process plans are created based on part and product information, as well as manufacturing information.

GENERIC OBJECT

An object that has a single generalized definition that is shared in many places in the design. For example, a general beam shape that is used in many places in a steel structure is a generic object. A generic object may be based on other generic objects and can have an arbitrary number of attribute definitions. A generic object can be individual part or, it can be a large, complex assembly. Generic objects can be non-mechanical such as forces or pressures acting on the assembly.

GHOSTING

A technology that enhances revolutionary panning and zooming capabilities on high-performance image display software.

GOPHER

A menu system for delivering documents over the Internet. It allows access for users that have not installed special software

GOUGE

Damaging the part due to tool motion entering the bounds of the desired finished part.

GROUP

A collection of elements.

HARDCOPY

Any document on paper or other full-size form, either output or not yet scanned. A printed copy of machine output in a readable form, for example, output from a computer printer. An enlarged reproduction from a microfilm usually on paper.

HARDWARE

Equipment, as opposed to software.

HERTZ

cycles per second or some repeated action per second - hz.

HIDDEN LINE

A wireframe display option that displays only the lines that should be visible from the current view.

HIGH-LEVEL LANGUAGE

A problem-oriented programming language using words, symbols, and command statements which closely resemble English-language statements.

HOLLERITH DATA

The descriptive information encoded on aperture cards. The data usually appears in visual form and as computer-readable punches.

HOME POSITION

A fixed location in the basic coordinate axis of the machine tool.

HOST

A mainframe computer or minicomputer that provides a multi-user environment and serves in the coordination of activities of the different users.

HTML (HYPERTEXT MARKUP LANGUAGE)

Used to describe World Wide Web documents and to provide links to other documents or hypertext.

HYBRID SOLID MODELER

An solid modeling database that actively maintains two or more substantially different representations of solid objects such as CSG and B-Rep.

HYPERTEXT

Technology for supporting embedded links within documents. A document with hypertext links can move easily to the document to which the link points.

IGES (INITIAL GRAPHICS EXCHANGE SPECIFICATION)

A standard for exchanging mechanical design data between CAD systems.

IMAGE

Electronic representation of a document, stored and displayed as a bitmap. Various compression techniques are in use to minimize file size and network load.

IMAGING

Term commonly used to describe both the products and industry dealing with images.

IML (INNER MOLD LINE)

The inner surface of the finished composite part (also, the top surface of the panel after it has been laid-up in the mold). It is often considered to be a very useful deliverable from the composite design process, especially for building the additional tooling and molds that are required to fabricate the part.

IMPLICITLY DEFINED

Information that is defined by a situation rather than by explicit definition. In solid modeling, an edge defined as the intersection of two surfaces is implicitly defined.

INFORMATION FLOAT

Time interval between generation or capture of information and its availability to the user.

INFORMATION SUPERHIGHWAY

High capacity global network of high speed computer based communications.

INFORMATION TOOL

Combination of hardware and software that supports or performs information work.

INTELLIGENT WORKSTATION

A workstation in a system which can perform certain data processing functions in a stand-alone mode, independent of another computer. Contains a built-in computer, usually a microprocessor or minicomputer, and dedicated memory.

INTERFACE

The place at which two systems meet and interact with each other. The interface can be a piece of hardware, a common area of computer storage or some common instruction shared by two or more programs. Also hardware, including device driver software that connects peripheral devices to computer platforms and to networks. Interfacing can imply network and operating protocols, codes and operating standards.

INTERFERENCE CHECKING

A CAD/CAM capability that enables mechanical designers to automatically examine intersection of objects within a 3D model.

INTERNATIONALIZATION

A process by which a product can be customized based on a language translation. Internationalization provides a better match of products in the global market.

INTERNET

A network to which many universities, government institutions and commercial organizations are connected, for person to person communication and information retrieval worldwide. The cost of using Internet is only that of a local telephone call, regardless of distance.

INTERNET ADDRESS

The unique computer address assigned to the network component of a particular computer. This address identifies the computer to all other the computers on the network.

IRC (INTERNET-RELAY CHAT)

A real-time conference service; the participants have an electronic dialogue. It can be used for holding conferences between people in different continents.

INTEROPERABILITY

Related to the examination of the information exchange between two specific CAD systems, and the ability of each CAD system to use such information.

IPO

The IGES/PDES Organization that develops and maintains the IGES standard and provides input to ISO for the PDES/STEP standard.

ISLANDS OF AUTOMATION

Stand-Alone automation products (robots, CAD/CAM systems, NC machines) without the integration required for a cohesive system.

ISO (INTERNATIONAL STANDARDS ORGANIZATION)

An international standards organizations that is similar in function to ANSI. They do not create standards but as with ANSI the provided a means of verifying that a proposed standard has met certain requirements for due process, consensus, and other criteria by those developing the standard. After this verification the standard is approved as an international standards by ISO.

ISO 9000

A series of international standards that provides quality management guidance and identifies quality system elements that are necessary for quality assurance. In other words, the ISO 9000 series standards have two main roles: to provide guidance for suppliers of all types of products that wish to implement effective quality systems (or improve existing ones); and to provide the generic requirements against which that quality system can be evaluated.

ISO DRAFTING STANDARD

An acronym for the International Standards Organization.

IT (INFORMATION TECHNOLOGY)

The acquisition, processing, storage and dissemination of vocal, pictorial, textual and numerical information by a microelectronics based combination of computing, telecommunications and video.

JPEG (JOINT PHOTOGRAPHIC EXPERTS GROUP):

A widely accepted, international standard for compression of color images.

JOURNALING

The process of creating a sequential record of images and database transactions. This record can be used to recreate a damaged system.

JUKEBOX

A robotic device that holds multiple optical drives and optical disks. The robotic device selects the appropriate platter to store or retrieve and places it on the drive.

KINEMATICS

Refers to the study of multibody systems (mechanisms, linkages, or other mechanical systems or subsystems) undergoing large-displacement motion, not taking into account the effects of applied or inertial forces.

KILOBYTE

one thousand bytes - Kb.

KNOWLEDGE BASE DESIGN

Collection of rules, facts, and data to be used in the design of products.

KNOT

Parameter value that indicates where on a curve or surface a pole's influence terminates.

LACE CUTTING

Milling operation where the tool moves back and forth in the cut, stepping to the side after each "lace."

LAMINATED OBJECT MANUFACTURING (LOM)

A patented process by Helisys of producing a physical prototype directly from a 3D surface or solid model.

LAN (LOCAL AREA NETWORK)

A network designed to connect devices over short distances. A data communications system that offers high-speed communication channels optimized for connecting information processing equipment over short distances. Consists of protocols and software to drive networks. Typically, these networks can transmit data at up to one megabyte per second. Protocol standards are token passing (Token Ring, Arcnet) and contention controlled (Ethernet).

LATENT SURFACES

Surfaces that are no longer visible after a boolean or intersection operation because they lie inside or outside the solid.

LAYER

A logical separation of data to be viewed individually or in combination. Similar in concept to transparent acetate overlays.

LAY-UP

The process of layering, or stacking up plies to build a composite part.

LEGACY DATA

Existing data that has been acquired by an organization.

LINE

A 2D geometric entity represented by a directional vector. A line will occupy a finite section of the vector defined by two endpoints.

LOAD DEFLECTION

The difference in position between a loaded and non-loaded points on an object.

LOFTING

The process of fitting a surface between two or more differing control profiles.

MACHINE COORDS

Coordinate system referenced by machine tool.

MAGNETIC TAPE

The preferred physical medium for delivery of technical data in digital form because it is a mature, stable technology that is able to handle large volumes of data.

MARKUP

The vector overlay that is created during the redline or annotation process. Markups can be stored a separate files, transferred and loaded individually or as a group. Markups can be rasterized into the base raster file.

MASS PROPERTIES

Properties of a solid which include volume, weight, center of gravity, planar, axial, polar moments of inertia, and radii or gyration.

MRP (MATERIAL REQUIREMENTS PLANNING)

The computerized method for planning the utilization of a company's resources in manufacturing, including scheduling, vendor selection, material alternatives.

MECHANICAL SYSTEM

A collection of parts or components that are connected to each other by joints, and that move or articulate in two or three dimensions.

MECHANICAL SYSTEM SIMULATION (MSS)

A software-based engineering discipline that entails modeling a mechanical system, simulating and visualizing its 3D motion behavior under real-world operating conditions, and refining/optimizing the design through iterative design studies prior to building the first physical prototype.

MEGABYTE

one million bytes - Mb.

METAL FABRICATION

Manufacturing processes of metal shaping and forming (as opposed to material removal).

MIRRORING

A CAD design aid which automatically creates a mirror image of a graphic entity on the CRT by flipping the entity or drawing.

MODEL

Graphic representation or schema.

MODEL SPACE

An electronic space defined in terms of three-dimensional coordinates where 3D modeling takes place.

MOTIF

The leading window manager for the X Window System. Motif provides the interface between applications and X Window. A style guide is published to promote standardization of user interfaces. Motif is sold by the Open Software Foundation (OSF).

MPEG (MOTION PICTURES EXPERTS GROUP)

An emerging standard for compression of full motion images driven by the same committee as the Joint Photographic Experts Group (JPEG) standard.

MULTIMEDIA

The discipline of integrating audio and pictorial data, in Information Technology, often for education and training applications. This information can be stored on CD-ROM. Typically associated with PCs, but increasingly associated with networked-based applications.

MIME (MULTIMEDIA INTERNET MAIL EXTENSIONS)

A standard for transmitting multimedia information through e-mail.

NATIONALIZATION

A process by which a product is customized based on a particular nation. Nationalization goes beyond internationalization by providing a mechanism for organizing the presentation based on the user's culture as well as language.

NC (NUMERICAL CONTROL)

A technique of operating machine tools by software commands.

NESTING

The arrangement of shapes within the stock area to maximize material use and to minimize scrap.

NETWORK

A system of computers, terminals and databases connected by communications lines, which allows the exchange of information and files.

NETWORK ARCHITECTURE

The organizational concept enabling communications between data processing equipment at multiple locations. The network architecture specifies the processors and terminals and defines the protocols and software that must be used to accomplish accurate data communications.

NFS (NETWORK FILE SYSTEM)

A vehicle by which users can identify networked storage media as local. This allows the local storage of small workstations to appear much larger than they are in reality.

NIBBLING

A series of cut-producing blows in rapid succession to contour a shape from sheet metal.

NIST (NATIONAL INSTITUTE OF STANDARDS AND TECHNOLOGY)

Created in 1901 as the National Bureau of Standards and renamed in 1988, the National Institute of Standards and Technology (NIST) works to strengthen U.S. industry's international competitiveness, advance science, and improve public health, safety and the environment. NIST conducts science and engineering research in commercially important fields such as advanced materials, information systems, biotechnology, optoelectronics, computer-integrated manufacturing, and sensor technology.

NODE

The basic graph element used to represent distinct items (vertices, faces, etc.). A signal coordinate in a grid. Finite element grid point used to discretize the structure. A node will lie on each vertex of a finite element, and additional nodes may lie along element edges to define curved element topology.

NORMAL

Planar profiles have a front and a back side. A normal is displayed as an arrow originating at the center of and at right angles to each face. Normals point towards the viewer for faces drawn in counterclockwise order. For a solid, all surface normals should point outward.

NURBS (NON-UNIFORM RATIONAL B-SPLINES)

A mathematical description of a surface created by two (or more) B-splines.

OBJECT

An item that shares certain characteristics with other items. These are classes as an object and rules are then applied to the class.

OBJECT ORIENTED

A term frequently used to describe a philosophy that examines data objects rather than function when designing systems.

OCR (OPTICAL CHARACTER RECOGNITION)

Automatic identification of text through a machine process. This process is often used to populate full-text databases and for auto-indexing.

OPEN ARCHITECTURE

The incorporation of standard interfacing features in both the hardware and software of a computer system, allowing communication with other components that incorporate the same standard interfacing features.

OPERATION

Usually a series of cuts performed to machine a part. One operation is defined by all the cuts performed with a single tool or fixture set-up.

OPTICAL DISK

An unalterable optical storage medium that allows large amounts of data to be permanently written to it. An optical disk is read using laser and magnetic technology and has a useful life span of 100 plus years.

OPTIMIZATION

A process that uses a computer to determine the best engineering design, such as lowest cost, best fuel efficiency, and ease of maintenance.

OML (OUTER MOLD LINE)

The outer, or external surface of the finished composite part (also, the mold surface to which the composite part conforms). The creation of a composite part begins by defining the OML.

OS/2

New operating system for IBM PCs from IBM.

OSF (OPEN SOFTWARE FOUNDATION)

A not-for-profit research and development organization that builds and delivers an open software environment based on standards for the benefit of the information processing industry. OSF uses an innovative open process, soliciting technologies from the industry-at-large, and delivering the technology in source code form. OSF develops and sells the Motif X Window manager.

OUTPUT

Last, an engineer decides types of output that is needed - bill of materials, CAD data, cost estimates, numerical control, engineering reports process plans, MRP, etc. The type of output needed determines the attribute information that is required about each object.

PAN

The process of moving the display window to view different areas of a drawing. This is done most commonly by depressing the pan button and moving the mouse.

PARAMETRIC CAD SYSTEM

A type of modern CAD system that lets you relate the geometry of different elements of a product. when you change one element, the geometry of the rest of the product changes as well.

PC (PERSONAL COMPUTER)

In this text it is used to refer to IBM PCs or clones.

PDES

Acronym for Product Data Exchange using STEP.

PDES/STEP

A set of standards under development for communicating a complete product model with sufficient information content that advanced CAD/CAM applications can interpret. PDES is under development as a national (U.S.) standard and STEP is under development as its international counterpart.

PDM (PRODUCT DATA MANAGEMENT)

A technology for management all engineering manufacturing data for a product to control the product development cycle.

PECKING

Drilling process where the tool is driven into the workpiece for a portion of the total depth, then retracted, then driven back in, retracted, etc.

PHIGS

Programmer's Hierarchical Interface Graphics Standard.

PIXEL

The fundamental element of a computerized image, short for picture element.

PLANE

Spatial element in 3D geometry that may or may not have a boundary, but is level and is 3D.

PLATFORM

A combination of computer hardware and an operating system.

PLY

A piece of composite cloth, which is soaked in epoxy and layered to make a composite part.

POINT

Graphic element representing a position in space.

POLYLINE

A geometric entity composed of one or more connected segments which are treated as single entity.

POSTPROCESSOR

A procedure, usually a computer program, that takes CL file information and translates CL file information into NC machine specific programming terms.

PPP

Point to point protocol, a standard protocol for dial-up telephone users to connect to the Internet directly. Without PPP, the user must dial into a host through a terminal session.

PRE-FORM

A small composite panel or subassembly which is embedded in a larger composite part.

PRESS BRAKE

A machine tool used to make straight bends in sheet metal.

PRIMITIVES

Simple or elemental. The lowest state of a solid model. A solid or surface that is not derived from other elements. A solid volume defined by simple standard geometrical shapes, such as a box, cone, and cylinder. Primitives are used by the CSG modeling method.

PROCESS PLANNING

The set of instructions for product fabrication.

PRODUCT CYCLE

The total of all steps leading from concept of a product to its manufacture.

PRODUCT DATA

All engineering data, in processable form, necessary to define the geometry, the function, and the behavior of an item over its entire life span, including logistic elements for quality, reliability, maintainability, topology, relationship, tolerances, attributes, and features necessary to define the item completely for the purpose of design, analysis, manufacture, test, and inspection.

PRODUCT MODEL

A data model that contains the functions and physical characteristics of each unit of a product throughout its complete life cycle (from requirements specification to disposal).

PRODUCT STRUCTURE

The definition and organization of the objects. Product Structures can be organized in any manner that is appropriate for the design; the most common way is by assembly. A product structure that is organized by assembly for airplane would include wings, fuselage, engine.

PROFICIENCY TESTS

A method of determining knowledge and level of proficiency in the use of CAD/CAM technology. Such tests are usually customized for relevance to a typical work environment.

PROSTEP

The center for STEP in Germany.

PROTOCOL

A defined communication format that contains the control procedures required to facilitate data transfer across the link interfaces, and to and from the user's application programs. A set of rules that specify how data communication is to take place over a network. These rules govern the format, timing, sequencing and error control of exchanged data.

PUNCH

A single blow to a piece of sheet metal to perforate the stock in the shape of the punch tool.

PUNCH PRESS

Machine tool used to punch holes or nibble contours into sheet metal.

QUERY

A request for information entered while the computer system is processing.

QUERY LANGUAGE

In DBMSs, an alternative to conventional programming languages that allows users to formulate ad hoc information retrieval request. See also SQL.

QUEUE

Storage areas within a computer system, with each item in storage linked to the items before and after it to form a queue or line. Queues are usually created to permit an individual operator to send data to be processed and then continue to perform other work rather than waiting for access to the appropriate function or peripheral.

RANDOM-ACCESS MEMORY (RAM)

Thought of as temporary memory because when the computer is turned off, all data stored in RAM is lost. To run a computer software application, it must be loaded into RAM. All computer programs (software) have a minimum RAM requirement.

RAPID PROTOTYPING

The process of producing a physical prototype directly for CAD 3D surface or solid modeling data by a number of patented processes such as SLA, LOM, FDM, SGC, or SLS.

RASTER

A two-dimensional array of black and white cells, called pixels or picture elements, which when displayed on a screen or paper, form an image or representation of an original document.

RASTERIZATION

The process that automatically converts vector and text into raster. This process is done on-the-fly for plotting, or can be stored as a file in raster format.

RAW MATERIALS

Materials from the mill before any machining operations.

REAL-TIME

The description for an operating system that responds to an external event within a short and predictable time frame. Unlike a batch or time-sharing operating system, a real-time operating system provides services or control to independent ongoing physical processes.

REDLINE

See Markup.

RELATIONAL

The term used to describe a database system that models relationships between objects.

RELATIONAL DATABASE

A software program which allows users to obtain information drawn from two or more data bases that are made up of two-dimensional arrays of data.

RENDERING

Process of adding shading, colors, reflectivity, textures, etc., to a model to make it appear realistic.

RETRACT

Machining move which removes the tool from the cut.

ROTARY TABLE

A table attached to a milling machine to which the workpiece is fixtured. The table may then be positioned to reorient the workpiece during the machining process.

ROUGHING

Operation to remove large amounts of material prior to the finishing cut.

RULE

A modular structure that represents a portion of knowledge.

RULE-BASED DESIGN

The definition of relationships between objects in the design. Another name used to describe knowledge-based design.

RULED SURFACE

A surface generated by linear interpolation between two lines or curves, or a point and a line or curve.

SCALING

An operation that changes the dimensions of a drawing by an operator entered multiplication factor. This operation can be performed in one or more directions. A mechanism for resizing part or all of an image.

SCULPTURED SURFACE

A free-form surface that is curved in more than one direction, typically by NURBS, Bezier, or other mathematical definitions.

SERVER

A computer dedicated to a single purpose for multiple users on a network. An example is the print server, which is dedicated to the handling of print requests.

SET

A popular European geometric data exchange standard started by a French company, Aerospatial.

SETBACK

The allowance for material stretch when metal is bent by press brake.

SEWING

The process of attaching surfaces at their mating edges to form a closed volume. Sewing can join two surfaces or allow the database to refer to them as a surface set as long as they share edges within a specified system tolerance.

SGC (SOLID GROUND CURING)

A patented process by Cubital for producing a physical prototype directly from a 3D surface of solid model.

SHELL

A solid model defined by a surface, thickness, and surface normals, such as formed sheet metal.

SINGLE PRECISION

Numbers stored in a computer using a single computer word.

SLA (STEREOLITHOGRAPHY)

A patented process by 3D Systems for producing a physical prototype directly from a 3D surface of solid model.

SLS (SELECTIVE LASER SINTERING)

A patented process by DTM Corporation for producing a physical prototype directly from a 3D surface of solid model.

SOFTWARE

The programs, routines and symbolic languages that control the functioning of the hardware and direct its operation.

SPECKLE REMOVAL

The process of removing speckles from a dirty image. Speckles are groups of pixels that constitute background noise on an image.

SPINDLE

Rotating head of machine tool. Milling spindle rotates the milling tool. Lathe spindle usually rotates the workpiece.

SPINDLE SPEED

Programmable rotation speed of the spindle.

SPIRAL CUTTING

Type of milling cut where the tool begins in the geometric center of the area being machined and spirals its way out to the outside bounds.

SPLINE

Mathematical interpolation routine for describing curves or surfaces.

SPRING PASSES

Creating of multiple passes for finishing operations. This allows for compensation of tool bending during previous operations where the tool was removing greater amounts of material.

SQL (STRUCTURED QUERY LANGUAGE)

A language typically used to create, update and query relational databases.

STAMPING

Process of forming sheet metal through a series of single hits of tools.

STEP (STANDARD FOR THE EXCHANGE OF PRODUCT MODEL DATA)

ISO standard 10303. An international standard under development which will be used to describe a product in a neutral format over its complete life-cycle in a hardware-independent way.

SURFACE

A boundary defining an exterior face of a solid model. The surface is typically defined beyond the limits of the face. Enlarging the extent of the face still yields a valid face on the solid.

SURFACE MODELING

Geometric modeling method that describes a part by it surfaces.

TABLES

A representation of data in a relational database. Information is arranged in columns and rows. Tables are defined based on the objects and relationships between objects.

TAP

Procedure for creating internal threads.

TAPE SET

A group of one or more magnetic tapes which collectively represent the collection of related files comprising a specific delivery of a document or documents.

TCP/IP (TRANSFER CONTROL PROTOCOL/INTERNET PROTOCOL)

A set of de facto networking standards commonly used over Ethernet wiring and X.25 networks. It was originally developed by the U.S. Government and is now supported by many equipment manufacturers.

TDP (TECHNICAL DATA PACKAGE)

A technical description that is adequate to support acquisition of an item, including engineering and production, the description consisting of all applicable technical data such as engineering drawings, associated lists, product and process specifications and standards, performance requirements, quality assurance provisions, and packaging details.

TECHNICAL DATA

Recorded information, regardless of form or method of the recording of a scientific or technical nature (including software documentation). The term does not include computer software or data incidental to contract administration, such as financial and/or management information.

TECHNICAL INFORMATION SYSTEMS

The generic term for the enterprise network of existing and augmented automated data processing systems used by government and contractors for management of technical information in support of the design, manufacture, and logistic processes for products such as weapon systems and related major equipment items.

TELNET

A terminal emulation protocol that lets you logon to other computers on the internet. Once logged on you can retrieve files from or send files to that remote computer.

TESSELLATING

Subdividing a patch element into face elements and a curve element into a line element. Tessellation lines are lines which connect tessellated elements.

TEXT FILE

A file which uses the American Standard Code for Information Interchange (ASCII) or similar system to represent the text of a document. Data within a text file are delineated as human readable words, sentences, and paragraphs rather than data elements.

TEXT-GRAPHICS INTEGRATION

The necessary indexing and linkages between a computer readable text file and a separate computer readable graphics file, or graphics subsection of the same text file, such that both portions can be output or updated as a single, apparently continuous, unit.

TERMINAL EMULATION

The network process that allows one computer to emulate another. Terminal emulation allows interaction with a networked computer as if the users were actually seated at the networked computer.

THREAD HOBB

Tool used for milling of internal or external thread

TIFF (Tagged Image File Format)

An industry standard raster file format, which consists of the image and header information. TIFF is also supported by most desktop publishing and paint programs.

TOLERANCE STACK-UP

The accumulative tolerance of mating parts.

TOTAL QUALITY MANAGEMENT (TQM)

Interfunctional approach to quality management, developed by Joseph Juran, involving marketing, engineering, manufacturing, purchasing, etc. Defects should be defined through examining customer expectations. The focus is on prevention, detection, and elimination of sources of defects. The Juran total quality management trilogy is quality control, quality planning, and quality projects.

TOKEN RING

A network topology originated and promoted by IBM Corporation. At the conceptual level, a token is created for the transfer of data along the network. The token is passed from one networked device to another until the matching device is located. The data is then delivered.

TOOL CHANGER

Machine tool component used to hold a variety of tools and to insert the programmed tool into the spindle.

TOOLPATH

In numerical control, the path of a cutting tool as it passes over stock material to produce desired shape.

TOOLPATH OPTIMIZATION

Collecting of similar tools in a program, to determine the most efficient paths.

TOP-DOWN DESIGN

An approach to assembly modeling where the organization or individual responsible for the overall assembly establishes the logical hierarchy of subassemblies and parts and assigns the creation of actual geometry to others.

TOPOLOGICAL DATA

Data which includes the connectivity relationships among geometric components.

TOPOLOGY

The relative location of geographic phenomena independent of their exact position. In digital data, topological relationships such as connectivity and relative position are usually expressed as relationships between nodes, links and polygons. Topology forms one of the crucial differences between raster and vector data. With topology, it becomes possible to join up the individual lines of a vector map to form shapes. In solid modeling, refers to the connections of individual elements (vertices, edges, and faces) of a solid model.

TORUS

A solid primitive defined by the revolution of a circle about an axis in the plane of the circle. The axis must not pass through the center of the circle, and must lie outside the circle.

TRANSFORMATION

Operations applied to a geometric database to perform translation, rotation, scaling, and perspective.

TREE

A method of file storage. The structure comprises a top-level, and one or more sublevels which may in turn contain sublevels, etc.

TRIMMED SURFACE

A surface that has a distinct boundary. The boundary of a trimmed surface is typically where the surface intersects other surfaces. This boundary may be represented by a set of curves, as in IGES.

TURNKEY SYSTEM

An integrated configuration of preselected hardware and prewritten software design to accomplish a particular information processing task. The term is most often applied to dedicated computer systems that use mini-computers or microcomputers.

UNIX

An open, multiple-user operating system developed by Bell Labs, now a de facto standard supported on a wide range of hardware and software. It is an operating system that supports multi-users and multi-tasking. Most workstations support some version of UNIX.

URL (UNIFORM RESOURCE LOCATOR)

Identifies a document or service on the Internet such as http://www.example.com

VAN (VALUE-ADDED NETWORK)

A system where a network leases communication lines from a communications common carrier, enhances them by adding improvements such as error detection and/or faster response time, and then allows others to use this service on those lines for a fee.

VARIATIONAL GEOMETRY

A method of representing a solid model as a set of interrelated equations defining its shape and dimensions. Variational geometry is solved simultaneously, as opposed to parametric geometry which is solved sequentially.

VDA

A data exchange standard, developed for the German automotive industry to exchange complex curve and surface data between auto suppliers and manufacturers.

VECTOR

An electronic or computer-readable image format incorporating a formulate representation of graphical line art. Vector format is used during the markup process, to keep redlines separate from images and to facilitate easy modifications. This format is also often used during the edit process.

VERTEX

An x-y-z location (a point in space) used to define an element. All types of elements consist of one or more vertices. Faces, lines, and point elements use vertices to represent points along their perimeters. Patch and curve elements (Bezier and B-spline) use vertices to represent control points.

VIRTUAL PROTOTYPING

Software-based engineering discipline that entails modeling a mechanical system, simulating and visualizing its 3D motion behavior under real-world operating conditions, and refining/optimizing the design through iterative design studies.... prior to building the first physical prototype.

VISC (VISUALIZATION IN SCIENTIFIC COMPUTING)

The use of computer technology for exploring data in visual form and for experiencing virtual worlds using all the human sensory channels. ...the use of computer graphics for acquiring a deeper understanding of data.

VOLUMETRIC SOLID MODELING

The use of solid models that are defined by spatial samples (such as CT scan data) rather than geometric shapes defined mathematically.

WAN (WIDE AREA NETWORK)

A communications network that links broad geographic areas.

WIP (WORK IN PROCESS)

Raw material undergoing change in the manufacturing process-before it becomes finished inventory.

WIREFRAME MODELING

A method of modeling geometry by using "wire." The geometry is described with lines, arcs, splines, etc. in 3D space.

WORKFLOW

The sequential management of document images through work queues and various application processes.

WORKPIECE

Piece of stock being machined.

WORKSTATION

A computer that can serve only one operator at a time and that commonly uses specialized software designed for engineering or other scientific applications; e.g., computer-aided drafting.

WWW (WORLD WIDE WEB)

A multimedia information system on the Internet for presenting pictures and sounds. It is very easy to use and to move from one Web system to another via a click of the mouse button.

WORM (WRITE ONCE, READ MANY)

An optical disk technology that permits the one-time creation of data, but multiple read access.

X CLIENT

The component of the X Window System that accepts requests from the X Server, processes them and returns data to the X Server for display. This definition of client is in contrast to the more common definition.

X SERVER

The component of the X Window System that presents data to the user. The X Server is located on the user's workstation and receives data back from the X Client. This definition of server is in contrast to the more common definition.

X WINDOW

The common term for The X Window System, a windowing environment for workstations that provides significant efficiency and power to users. X Window supports graphics display and is based on the client/server model.

ZOOM

The process of magnifying of the display of an image in a window to more closely inspect areas of a drawing.

ZOOM BOX

A navigation box that displays a reduced version of the current image and a box within it representing the current zoom level and position. The box assists in determining the user's location on the drawing.