VM&G Engineering Design Vocabulary, Chapters 1-5

assembly

A collection of parts that mate together to perform a specified function or functions.

CAD

Computer-aided drawing.

descriptive geometry

A two-dimensional graphical construction technique used for geometric analysis of three-dimensional objects.

design (noun)

An original manifestation of a device or method created for performing one or more useful functions.

design (verb)

The process of creating a design (noun).

drawing

A collection of images and other detailed graphical specifications intended to represent physical objects or processes for the purpose of accurately re-creating those objects or processes.

engineer (verb)

To plan and build a device that does not occur naturally within the environment.

engineer (noun)

A person who engages in the art of engineering.

engineering

The profession in which knowledge of mathematical and natural sciences gained by study, experience, and practice is applied with judgment to develop and utilize economically the materials and forces of nature for the benefit of humanity.

fabricate

To make something from existing materials.

image

A collection of printed, displayed, or imagined patterns intended to represent real objects, data, or processes.

instruments

In engineering drawing, mechanical devices used to aid in creating accurate and precise images.

model

A mathematical representation of an object or a device from which information about its function, appearance, or physical properties can be extracted.

optimization

Modification of shapes, sizes, and other variables to achieve the best performance based on predefined criteria.

part

A single object fabricated to perform one or more functions.

project

In engineering, a collection of tasks that must be performed to create, operate, or retire a system or device.

solid modeling

Three-dimensional modeling of parts and assemblies originally developed for mechanical engineering use but presently used in all engineering disciplines.

system

A collection of parts, assemblies, structures, and processes that work together to perform one or more prescribed functions.

three-dimensional (3-D) modeling

Mathematical modeling where the appearance, volumetric, and inertial properties of parts, assemblies, or structures are created with the assistance of computers and display devices.

two-dimensional (2-D) drawing

Mathematical modeling or drawing where the appearance of parts, assemblies, or structures are represented by a collection of two-dimensional geometric shapes.

visualization

The ability to create and manipulate mental images of devices or processes.

arc

A curved entity that represents a portion of a circle.

bounding box

A square box used to sketch circles or ellipses.

circle

A closed curved figure where all points on it are equidistant from its center point.

construction line

A faint line used in sketching to align items and define shapes.

ellipse

A closed curved figure where the sum of the distance between any point on the figure and its two foci is constant.

isometric axes

A set of three coordinate axes that are portrayed on the paper at 120 degrees relative to one another.

isometric dot paper

Paper used for sketching purposes that includes dots located along lines that meet at 120 degrees.

isometric grid paper

Paper used for sketching purposes that includes grid lines at 120 degrees relative to one another.

isometric pictorial

A sketch of an object that shows its three dimensions where isometric axes were used as the basis for defining the edges of the object.

left-handed system

Any 3-D coordinate system that is defined by the left-hand rule.

line

A spatial feature that marks the shortest distance between two points. A line has location, orientation, and length, but no area.

oblique axes

A set of three coordinate axes that are portrayed on the paper as two perpendicular lines, with the third axis meeting them at an angle, typically 45 degrees.

oblique pictorial

A sketch of an object that shows one face in the plane of the paper and the third dimension receding off at an angle relative to the face.

receding dimension

The portion of the object that appears to go back from the plane of the paper in an oblique pictorial.

right-hand rule

Used to define a 3-D coordinate system whereby by pointing the fingers of the right hand down the x-axis and curling them in the direction of the y-axis, the thumb will point down the z-axis.

right-handed system

Any 3-D coordinate system that is defined by the right-hand rule.

shading

Marks added to surfaces and features of a sketch to highlight 3-D effects.

3-D coordinate system

A set of three mutually perpendicular axes used to define 3-D space.

tick mark

A short dash used in sketching to locate points on the paper.

Boolean operations

In early versions of 3-D CAD software, commands used to combine solids.

combining solids

The process of cutting, joining, or intersecting two objects to form a third object.

corner views

An isometric view of an object created from the perspective at a given corner of the object.

cross section

The intersection between a cutting plane and a 3-D object.

cut

To remove the volume of interference between two objects from one of the objects.

cutting plane

An imaginary plane that intersects with an object to form a cross section.

intersect

To create a new object that consists of the volume of interference between two objects.

join

To absorb the volume of interference between two objects to form a third object.

mental rotations

The ability to mentally turn an object in space.

reflection

The process of obtaining a mirror image of an object from a plane of reflection.

spatial orientation

The ability of a person to mentally determine his own location and orientation within a given environment.

spatial perception

The ability to identify horizontal and vertical directions.

spatial relations

The ability to visualize the relationship between two objects in space, i.e., overlapping or nonoverlapping.

spatial visualization

The ability to mentally transform (rotate, translate, or mirror) or to mentally alter (twist, fold, or invert) 2-D figures and/or 3-D objects.

symmetry

The characteristic of an object in which one half of the object is a mirror image of the other half.

volume of interference

The volume that is common between two overlapping objects.

CAD designers

Designers who create 3-D computer models for analysis and detailing.

chief designer

The individual who oversees other members of the design team and manages the overall project.

computer-aided design (CAD)

The process by which computers are used to model and analyze designed products.

computer-aided manufacturing (CAM)

The process by which parts are manufactured directly from 3-D computer models.

concept mapping

The creative process by which the central idea is placed in the middle of a page and related concepts radiate out from that central idea.

conceptual design

The initial idea for a design before analysis has been performed.

concurrent engineering

The process by which designers, analysts, and manufacturers work together from the start to design a product.

design analysts

Individuals who analyze design concepts by computer methods to determine their structural, thermal, or vibration characteristics.

design documentation

The set of drawings and specifications that illustrate and thoroughly describe a designed product.

design process

The multistep, iterative process by which products are conceived and produced.

detail designers

The individuals who create engineering drawings, complete with annotation, from 3-D computer models or from engineering sketches.

engineering design

The process by which many competing factors of a product are weighed to select the best alternative in terms of cost, sustainability, and function.

finite element analysis (FEA)

A numerical method used to analyze a product in terms of its structural, thermal, and vibrational performance.

green engineering

The process by which environmental and life cycle considerations are examined from the outset in design.

industrial designers

The individuals who use their creative abilities to develop conceptual designs of potential products.

life cycle

The amount of time a product will be used before it is no longer effective.

mass properties analysis

A computer-generated document that gives the mechanical properties of a 3-D solid model.

model builders

Engineers who make physical mock-ups of designs using modern rapid prototyping and CAM equipment.

morphological chart

A chart used to generate ideas about the desirable qualities of a product and all of the possible options for achieving them.

problem identification

The first stage in the design process where the need for a product or a product modification is clearly defined.

prototype

The initial creation of a product for testing and analysis before it is mass-produced.

sustainable design

A paradigm for making design decisions based on environmental considerations and life cycle analysis.

visual thinking

A method for creative thinking, usually through sketching, where visual feedback assists in the development of creative ideas.

weighted decision table

A matrix used to weigh design options to determine the best possible design characteristics.

algebraic constraints

Constraint that define the value of a selected variable as the result of an algebraic expression containing other variables from the solid model.

associative constraints

See algebraic constraints.

base feature

The first feature created for a part, usually a protrusion.

blend

A solid formed by a smooth transition between two or more profiles.

blind extrusion

An extrusion made to a specified length in a selected direction.

boundary representation (b-rep)

A method used to build solid models from their bounding surfaces.

chamfers

Angled cut transitions between two intersecting surfaces.

child feature

A feature that is dependent upon the existence of a previously created feature.

constraints

Geometric relationships, dimensions, or equations that control the size, shape, and/or orientation of entities in a sketch or solid model.

constructive solid geometry (CSg)

A method used to build solid models from primitive shapes based on Boolean set theory.

cosmetic features

Features that modify the appearance of the surface but do not alter the size or shape of the object.

cut

A feature created by the removal of solid volume from a model.

database

A collection of information for a computer and a method for interpretation of the information from which the original model can be re-created.

datum geometries

Geometric entities such as points, axes, and planes that do not actually exist on real parts, but are used to help locate and define other features.

datum planes

The planes used to define the locations of features and entities in the construction of a solid model.

design table

A table or spreadsheet that lists all of the versions of a family model, the dimensions or features that may change, and the values in any of its versions.

design tree

See model tree.

dimensional constraints

Measurements used to control the size or position of entities in a sketch.

dimension name

The unique alphanumeric designation of a variable dimension.

driven dimension

A variable connected to an algebraic constraint that can be modified only by user changes to the driving dimensions.