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Fundamentals of Graphics Communication, 3/e
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Bertoline - Fundamentals of Graphics Communication Third Edition

Glossary Q-R

Please click on the desired term below to view the glossary definition.
quadrilaterals  (n) Four-sided polygons of any shape. The sum of the angles inside a quadrilateral always equals 360 degrees. Quadrilaterals are classified by the characteristics of their sides. If opposite sides of the quadrilateral are parallel, the shape is a parallelogram.
qualitative  (adj.) A type of data used as a method of labeling and identifying. Qualitative data are classified as being either nominal or ordinal.
quality  (adj.) The capacity of a product or service to consistently meet or exceed customer needs and expectations. Quality includes performance, special features, reliability, durability, and service after sale.
quantitative  (adj.) A type of data that has numerical value. Quantitative data are further classified by the number of components and by the scales of values used (e.g., scalar, vector, or tensor).
radiosity  (n) A rendering technique, based on thermal principles, in which there is a conservation of light energy in a closed environment. With radiosity methods, any size or shape surface is capable of both radiating and absorbing light energy. The rate at which energy leaves a surface is its radiosity, and is the result of all light energy received, absorbed, and then transmitted by the surface.
radius symbol  (n) A symbol that precedes a numerical value, indicating that the associated dimension shows the radius of a circular arc. The radius symbol is the capital letter R.
range bars  (n) Line or bar marks, such as those used in bar charts, that indicate an interval of variable values. For example, range bars could be used to indicate the period of time that a product is in transit between machining stations on a manufacturing line.
rapid prototyping  (n) A broad term used to describe several related processes that create physical models directly from a CAD database. Prototyping systems use a variety of techniques, including stereolithography and fused deposition modeling (FDM). Rapid prototyping is used to create prototypes for concept modeling, injection molds, and investment casting.
ratio scale  (n) A data scale that has a natural zero point but is insensitive to the units used. Ratio values are often generated by dividing two values that have either similar or dissimilar units.
rats nest  (n) The drawing representing straight-line connections between all of the electronic components on a printed circuit board. Once the components are located on the board, the rats nest is generated, using the component connection list. The rats nest drawing is part of the iterative design process to optimize placement of components.
ray  (n) An entity of unspecified length, but no depth or breadth, that extends into infinity from a specified point. In computer graphics, ray is a common term used, when rendering a scene, to describe the path a light ray follows.
ray tracing  (n) A rendering technique that calculates the path of all rays of (a) theoretical light source(s) within a model scene. The technique includes tracing the path from the light source, between all objects which may reflect and pass the light, to the viewer’s eye.
reach envelope  (n) A volume of space representing all possible locations in space that a human operator’s limbs could occupy. Reach envelopes are used to analyze the locations of controls, such as in the design of workstations, tools, cockpits, etc.
rear view  (n) A principal view of an object, created by rotating the object 180 degrees about the vertical axis from the front view. This view is not typically included in a standard multiview drawing.
reference dimension  (n) A numerical value, enclosed in parentheses, provided for information only and not used in the fabrication of the part. A reference dimension is a calculated size used to show the intended design size of a part. Drawings made to older standards may use REF placed next to a reference dimension, instead of using parentheses.
reference lines  (n) Lines used to correlate scale values with data markers in a visualization. Because reference lines are not the central focus of a visualization, they tend to be thin and sometimes dotted or dashed.
refinement  (v) A repetitive process (iterative or cyclical) used to test the preliminary design, make changes if necessary, and determine if the design meets the goals of the project. Models are used to analyze and visualize the design. Refinement drawings are used to analyze the design in its current stage of the design process.
regression line  (n) A line mark used in conjunction with point marks to represent data trends in a visualization. Although this line, either linear or curved, can be drawn freehand, it is usually calculated using statistical techniques.
regular curve  (n) A bent line composed of constant-radius arcs generated around a single centerpoint. With traditional tools, regular curves are drawn using a compass or circle template; with CAD, they are constructed with the CIRCLE and ARC commands.
regular isometric  (n) An isometric pictorial drawn as if the viewer is looking down on the object from the top. In a regular isometric, the 30-degree axes are drawn upward from the horizontal. The regular method is the most common type of isometric drawing.
related view  (n) Views that are adjacent to the same view in orthographic drawings. These views are called related because distances of common features are equal or related.
relative coordinates  (n) Coordinate locations specified in reference to a previously defined location other than the origin. Relative coordinates are sometimes referred to as delta coordinates, meaning changed coordinates.
removed section  (n) A section view that does not follow the standard alignment of views practiced in multiview drawing. This technique is used to show multiple section views generated from parallel cutting planes and views placed on separate drawings or using different scales.
removed view  (n) A complete or partial orthographic view that is not aligned with any of the principal views. Removed views are often shown on a different drawing sheet or at a different scale.
reprographics  (n) The process of storing, retrieving, and copying engineering drawings. Often, specialized service bureaus are used to provide these services to small firms.
reversed axis isometric  (n) A variation of the regular isometric pictorial. Whereas in a regular isometric, it appears as though the viewer is looking down from the top of the object, in the reversed axis isometric, it appears as if the viewer is looking up from the bottom of the object. The 30-degree axes are drawn downward from the horizontal.
reverse engineering  (v) A method of accurately evaluating existing products, then inputting the information into a CAD database. Often a coordinate measuring machine (CMM), an electromechanical device with a probe on one end that accurately measures objects, is used to input the 3-D data into the CAD system.
revision block  (n) An area located next to the title block, listing the version, or revision, of the drawing depicted.
revolution  (v) The rotation of a point, line, plane, or entire object about an axis parallel to a plane or projection. The revolution method is one of the standard techniques used in descriptive geometry.
revolved section  (n) A section view made by revolving the cross-section view of the part 90 degrees and placing the section view on the part. Visible lines adjacent to the revolved view can be either drawn or broken out using conventional breaks.
RGB color model  (n) A color model based on the three additive primaries: (R)ed, (G)reen, and (B)lue. This color model is used extensively because of its close correlation to the hardware implementation of color on a computer monitor.
rib (web)  (n) A thin, flat feature of an object that acts as a structural support. Ribs, webs, spokes, lugs and other thin features are not section lined if a cutting plane passes parallel to the feature.
right side view  (n) A principal view of an object, created by rotating the line of sight 90 degrees about the vertical axis to the right of the front view. This view is typically included in a standard multiview drawing.
rigid-body transformations  (n) Transformations applied to geometric forms. Such transformations affect the location or orientation in space but not the shape. Examples are translation and rotation.
rivet  (n) A permanent mechanical fastener, consisting of a smooth metal shaft with a head. Rivets are placed in the part and held in place by spreading the tip protruding through the material.
robot  (n) A computer-controlled device used in manufacturing for many purposes, such as assembly, painting, and material movement. Robotics is an important component of CAD/CAM and in the automation of production facilities.
root  (n) A threading term used to describe the bottom of a screw thread cut into a cylinder.
roulette  (n) The curve generated by the rolling contact of one curve or line on another. Any point attached to the rolling curve will describe a roulette curve. The moving point is called the generating point. The roulette is constructed by moving the rolling curve to a number of new positions and plotting the corresponding positions of the generating point.
round  (n) A round is an exterior corner normally found on cast, forged, or molded parts. Like a fillet, a round can indicate that a surface is not machined finished. A round is indicated on engineering drawings as a small arc.
roundness  (n) See circularity.
rule 1  (n) A central principle to geometric dimensioning and tolerancing (ANSI Y14.5– 1982). It stated that, where only a tolerance of size is specified, the limits of size of an individual feature prescribe the extent to which variations in its geometric form, as well as its size, are allowed.
ruled surface  (n) A surface produced by the movement of a straight-line generatrix controlled by a directrix to form a plane, a single-curved surface, or a warped surface.
runout  (n) A filleted surface that runs tangent to a cylindrical one. A runout is drawn on multiview drawings starting at the point of tangency, using a radius equal to that of the filleted surface, with a curvature of approximately one-eighth of a circle.