Student Center | Instructor Center | Information Center | Home
Fundamentals of Graphics Communication, 3/e
Student Center
Career Opportunities
Frequently Asked Q...
AutoCAD Starter Fi...
Glossary A
Glossary B
Glossary C
Glossary D
Glossary E-F
Glossary G-H
Glossary I
Glossary J-L
Glossary M
Glossary N-O
Glossary P
Glossary Q-R
Glossary S
Glossary T
Glossary U-Z


Feedback
Help Center



Bertoline - Fundamentals of Graphics Communication Third Edition

Glossary P

Please click on the desired term below to view the glossary definition.
painter’s algorithm  (n) A rendering technique used to perform hidden surface removal. All of the polygons are sorted and then drawn on the screen from back to front. Both the computer and a painter use this technique to ensure that elements in the background are covered by those in the front.
parabola  (n) A single-curved surface primitive, defined as the curve of intersection created when a plane intersects a right circular cone parallel to one of the cone’s elements.
parallelism  (n) An orientation control for geometric dimensioning and tolerancing. Parallelism is a condition in which a surface or an axis is equidistant at all points from a datum plane or datum axis, respectively. The distance between the feature and the datum is the tolerance value given in the control frame.
parallel lines  (n) Two lines in a plane that stay equidistant from each other along their entire logical length. The lines can be straight or curved. Circular curved parallel lines share the same center point and are referred to as concentric.
parallelogram  (n) A quadrilateral (four-sided polygon) in which opposite sides are parallel. The square, rectangle, rhombus, and rhomboid are all parallelograms.
parallel planes  (n) Two planes that are equidistant from each other over their entire surfaces. Two planes are considered parallel when intersecting lines in one plane are parallel to intersecting lines in the second plane. Also, seen in edge view, the two planes appear as parallel lines.
parallel projection  (n) A projection technique in which all the projectors are parallel to each other, eliminating convergence. All major projection techniques, except perspective, use parallel projection.
parametric  (adj.) A term used to classify curves for which the path is described by a mathematical function rather than a set of coordinates. A parameter within the function (often specified as u or v) is varied from 0 to 1 to define all the coordinate points along the curve.
parent-child  (n) Describes the relationship between features in a model. The parent is created first and the child feature is dependent on the parent feature for its definition in some way. An example would be that workplane might be the parent of a swept feature if the workplane was used in part to define the feature profile of the sweep.
partial view  (n) A view that shows only what is necessary to completely describe the object. Partial views are used for symmetrical objects, for some types of auxiliary views, and for some types of multiview drawings. A break line or center line may be used to limit the partial view.
patch  (n) A closed series of parametric curves that describe a surface region. Series of patches are usually combined together in surface modeling systems to describe an object.
patent  (n) The “right to exclude others from making, using, or selling . . .” a product, granted by the federal government for a period of 17 years. The patenting process was developed to encourage the free and prompt disclosure of technical advances. Patents often require specialized graphics as supporting documentation.
PCB  (n) Acronym for printed circuit board, a rigid board typically made from fiberglass, approximately .060" thick, and used for mounting electronics components as part of a larger assembly. This board, also called a printed wiring board (PWB), has wiring patterns formed by traces of a conductor, such as copper, fused to the board. The wiring pattern is created either by depositing the conductor on the board or by starting with a solid film of the conductor and etching away what is not needed.
PDES  (n) An acronym for product data exchange using STEP, a new data exchange standard that attempts to incorporate information for the complete life cycle of the product. The type of information covered includes shape, design, manufacturing, quality assurance, testing, support, etc. As indicated by its name, PDES incorporates the evolving STEP standard.
perception  (n) The mental image or knowledge of the environment received through the senses. Real objects can be perceived through viewing or touching, whereas graphic representations are perceived through viewing alone.
perfect form  (n) A term used in geometric dimensioning and tolerancing to describe the ideal shape of a feature. Form controls on a feature are defined relative to the perfect form. For example, the cylindricity tolerance zone is defined as a perfect cylindrical shape.
perimeter loop  (n) A closed set of edges and vertices that constitute the outer boundary of a face. The perimeter loop is a variable in the Euler–Poincaré formula used as part of the process of validating the topology of a model.
perpendicularity  (adj.) An orientation control for geometric dimensioning and tolerancing. Perpendicularity is the condition of a surface, center plane, or axis that is at a right angle to a datum plane or datum axis, respectively.
perpendicular lines  (n) Two or more lines that intersect once at a right angle (90 degrees), sometimes referred to as normal.
perpendicular planes  (n) Two planes oriented at right angles (90 degrees) to each other. Two planes each containing a line that is perpendicular to a line in the other plane, are also perpendicular to each other. Multiviews are generated by mutually perpendicular image planes.
perspective projection  (n) A projection technique in which some or all of the projectors converge at predefined points. This pictorial projection technique is used to replicate closely how humans perceive objects in the real world.
phantom line  (n) A line used to represent a moveable feature in its different positions as well as a repeating pattern, such as screw threads on a shaft.
PHIGS (Programmers’ Hierarchical Interactive Graphics System)  (n) A software program that can generate, display, and transfer computer graphics data in a compatible format.
Phong shading  (v) A rendering method that uniformly adjusts the value of a surface color based on the relationship of the light source to normals calculated along each edge of the model. Unlike Gouraud shading, Phong shading allows the representation of highlights arising from specular reflection.
photorealistic  (adj.) A term describing a rendered object that attempts to match the perceptual effects of color, texture, lighting, etc., of a real object. This type of rendering is used by industrial designers, marketing executives, and others interested in gaging the affects of its visual appearance.
physical prototypes  (n) Physical models of a proposed design. These are used in the evaluation and testing of a product before going into full production. Increasingly, simulated or virtual prototypes created with CAD/CAM tools are used for analysis.
pictorial assembly  (n) A pictorial drawing (normally an axonometric view) of a partially or fully disassembled assembly. Center lines, called flow lines in this application, are used to show how each part is assembled. The pictorial assembly is commonly used in installation and maintenance manuals.
pictorial drawing/sketch  (n) A drawing in which all three of the primary dimensions of an object are seen in a single view. These drawings are used to give a holistic view and are not used to depict specific features on the object. Axonometric and perspective pictorials are the two main types.
pin  (n) A mechanical fastener, typically cylindrical in shape, used to keep parts in position or to prevent slippage after assembly. Some of the more common types of pins are dowel, straight, tapered, groove, spring, and cotter.
pinion  (n) The smaller of two gears in a meshed pair of gears. The larger of the two gears is simply called the gear. A gear and pinion pair is used to change the speed of shaft rotation, with the pinion shaft rotating at a higher rate than the gear shaft.
piping  (n) A specialized engineering field for the design of fluid and gas-carrying piping systems for process plants and other industrial and commercial structures.
piping drawing  (n) A specialized drawing used in the design and maintenance of piping systems. The piping systems are shown in an orthographic plan view or in a pictorial view such as isometric. The drawing can be done as a single-line drawing in which the components are represented as a single line or as a double-line drawing for a more realistic spatial layout of the components. Specialized graphic symbols are used to represent the pipes, fittings, and valves used in the system.
pitch  (n) A thread term used to describe the distance measured parallel to the axis between corresponding points on adjacent thread forms. The pitch is equal to 1 divided by the number of threads per inch.
pixel  (n) A single point on a display device, such as a computer monitor. Pixels are arranged in horizontal and vertical rows. On a CRT type monitor, a pixel is an electronically charged point on the screen. Pixel is often used in describing the minimal unit of resolution of any bitmapped graphic output.
plan drawing  (n) A type of drawing commonly used in civil, architectural, or engineering projects involving large structural layouts. A plan drawing (sometimes called a plan view) is an orthographic view taken from the top and looking down parallel to the line of gravity. These drawings are useful in planning the flow of vehicles, people, or material through constructed spaces or along the terrain.
plane  A region of space defined by a minimum of three noncoincident points in space. For the simplest type of plane surface, all points can be described by two coordinate axes; that is, the plane has no curvature.
plane geometry  (n) The geometry of planar figures, such as circles and triangles, and their relationships. This mathematical field is an important part of traditional engineering and technical graphics.
plane of projection  (n) An imaginary plane in space upon which an object is projected. The plane can be imagined as a pane of glass on which lines of sight from the object form an outline of the object. This plane is also referred to as a picture plane.
plastics  (n) A material made from natural or synthetic resins that can be formed or shaped. Common industrial plastics include polystyrene, acrylics, polycarbonate, ABS, PVC, acetals, nylon, polypropylene, polyethylene, epoxy, and phenolics.
PLM (product lifecycle management)  (n) Product lifecycle management breaks down the technology silos that have limited interaction between the people who design products and the people who build, sell, and use them. Using the collaborative power of the Internet, PLM lets an organization begin innovative product design while reducing cycle times, streamlining manufacturing and cutting production costs.
plus and minus dimensioning  (n) A tolerancing specification that gives the allowable positive and negative variance from the dimension specified. Sometimes, the plus and minus values will be equal; at other times, they will be different.
point  (n) A singular location in space, usually defined by coordinate values (i.e., X,Y,Z).
point light source  (n) A light source located at a specified point in space. In rendering, the point light source is usually close to the model. Because the light radiates omnidirectionally from the point source, no two rays hit a planar surface at the same angle. An uncovered incandescent light bulb is analogous to a point light source.
point-to-point diagram  (n) See wiring diagram.
polar coordinates  (n) A 2-D coordinate system used to locate a point in a plane by specifying a distance and an angle from the coordinate origin. When another distance normal to the coordinate origin is added, cylindrical coordinates can be specified.
polygon  (n) A plane figure bounded by straight lines. If the sides are of equal length and form equal angles with each other, the polygon is considered a regular polygon (e.g., a square or hexagon).
polygonal prism  (n) A geometric solid consisting of two equivalent polygonal bases parallel to each other. Each equivalent edge of the bases is connected to form a series of parallelograms, bounding the sides of the solid.
polyhedron  (n) A geometric solid bounded by polygons. If the polygons are equal, regular polygons, the solid is called a regular polyhedron.
port  (n) In 3-D modeling systems, a defined region on the computer screen, used for displaying a single view of an object. Typically, a different set of view parameters is assigned to each port.
position  (n) A control for geometric dimensioning and tolerancing. Position specifies the total zone specification for a feature, such as a diameter or the total height.
precedence of lines  (n) A convention describing the order of priority of different linestyles. For example, if a visible and hidden line coincide, the visible line is the one drawn.
presentation graphics  (n) Graphics intended for a wide audience and used to communicate information about a proposed product or design to other individuals within the company, to clients, or to the potential end user.
pressure angle  (n) A term used in the design of gears and defined as the angle between the tangent to the pitch circles and the line drawn normal to the surface of a gear tooth. The pressure angle has been standardized by gear manufacturers and by ANSI (14 1/2 degrees being the most common), and it determines the shape of the involute curve used to design the gear tooth.
primary auxiliary view  (n) A single auxiliary view projected from one of the six standard views. Primary auxiliary views are used to show inclined surfaces in their true size and shape. Secondary auxiliary views are used for oblique surfaces and are derived from primary auxiliary views.
primary axes  (n) Three mutually perpendicular axes representing the primary dimensions of an object. Each of these axes is normal (perpendicular) to one of the primary image planes.
primitive  (n or adj.) A term used primarily to describe the fundamental geometric forms used for building 3-D CAD models. Primitives are typically defined parametrically or with single-sweep operations. Primitives are used as tool solids in Boolean operations.
principal (standard) view  (n) One of the six mutually perpendicular views of an object, produced after an object’s position is selected. The six views can be created by positioning the object inside a glass box and viewing the box with parallel lines of sight perpendicular to the glass planes. These views are the cornerstone of multiview drawings.
principal plane  (n) A plane that is seen in its true size and shape in two of the six principal views and as an edge in the other four. The three principal planes are frontal, profile, and horizontal. For example, the frontal plane is seen in its true size and shape in the front and rear views and as an edge in the other four views.
printed circuit board  (n) See PCB
printed wiring board  (n) See PWB.
problem identification  (n) A process used by the design team during the ideation process to set the parameters of the design project before attempting to find a solution to the design. This process includes such stages as objectives, limitations, and scheduling.
procedural  (adj.) A term used to describe the process by which a model is constructed. Procedural information can be thought of as actions, such as creating a face on the cube by following the path made by edges 1 through 4.
process control  (n) The measurement, analysis, and adjustment of manufacturing processes, such as drilling, milling, and turning. The quality of a product relies heavily on process control techniques used to check the variability of machined parts and to detect defects. The use of statistical techniques is an important component of process control.
process planning  (n) The stage in the manufacturing process in which the most efficient way of producing the product is determined. In this stage, industrial engineers determine how parts will be fabricated and in what sequence.
product (industrial) design  (n) A complex activity that includes function analysis, market analysis, production, sales, and service. The goal of product design is to produce a product that will meet the wants and needs of the consumer, can be economically produced, is safe for the consumer and the environment, and will be profitable.
product data exchange using STEP  (n) See PDES.
production process  (n) The planned action used to convert raw materials into finished products. The production process is sometimes referred to as the manufacturing process. However, production is a more global term that includes both the manufacturing of products and the construction of structures.
profile  (n) A form control for geometric dimensioning and tolerancing. A profile is the outline of a feature projected onto a plane. They usually consist of combinations of contiguous lines, arcs, and other curves. The profile tolerance zone may be made of a combination of straightness, roundness, parallelism, etc.
profile line  (n) A line seen in its true length in the profile plane, either the right or left side view.
profile plane  (n) A principal orthographic plane of projection. This plane is used to define both the right and left side orthographic views.
profile sketch  (n) Typically a closed loop of lines drawn on a workplane as part of the feature definition process in 3-D modeling. In a constraint-based modeler, the profile sketch is constrained with dimensions and other geometric relations and then swept out to form a 3-D solid model feature.
profile view  (n) A principal orthographic view created by a projection onto the profile plane. This term includes both the right and left side views.
projection line  (n) A construction line drawn between views in a multiview drawing to align 3-D space dimensions. This term is sometimes used in a more general sense to refer to lines representing the transference of spatial information between objects, or between an object and an image plane. The relationship of the projection lines to each other and to the image plane defines whether the projection technique is perspective, parallel, or oblique.
projection theory  (n) The principles used to represent objects and structures graphically on 2-D media. Some of the primary projection methods include orthographic, oblique, and perspective.
proportion  (n) The comparative relation, or ratio, between dimensions of a feature or object.
prototyping  (n or v) A term used to describe the process by which physical mockups are made of proposed designs. Increasingly, prototyping is done using the databases associated with 3-D computer models. Because of the speed and efficiency, this technique is often referred to as rapid prototyping.
PWB (printed wiring board)  See PCB.
pyramid  (n) A geometric solid consisting of a polygonal base and a series of triangular lateral faces. The triangular faces each share one side with the polygonal base and the other two sides with the neighboring triangular faces. The triangular faces all meet at a common point called the vertex.