| adjacent areas | (n) Surfaces that are separated on a multiview drawing by lines that represent a change of planes. No two adjacent areas can lie in the same plane.
(See 343)
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| adjacent view | (n) Orthographic views that are aligned to each other, allowing dimensional information to be shared. Examples are the front and top views or the front and right side views.
(See 309)
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| alphabet of lines | (n) The standard linestyles established by ANSI to be used for technical drawing. The standards specify both the thickness and the design (i.e., dashed, solid, etc.) of the lines.
(See 311)
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| auxiliary view | (n) A view derived from any image plane other than the frontal, horizontal, or profile planes. Auxiliary views are usually termed primary or secondary, depending on whether or not they are perpendicular to one of the above-mentioned primary projection planes. Primary auxiliary views are termed depth, height, or width auxiliaries, depending on the dimension transferred from the measuring view.
(See 351)
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| blind hole | (n) A hole that does not go completely through the material. Blind holes can be created by any cutting device (such as a twist drill bit) that is capable of plunging into the material.
(See 333)
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| bottom view | (n) A principal view of an object, created by rotating the object 90 degrees about the horizontal axis below the front view. This view is not typically included in a standard multiview drawing.
(See 307)
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| central view | (n) The view from which related views are aligned in an orthographic drawing. Distances and features are projected or measured from the central view to create the adjacent views.
(See 311)
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| chamfer | (n or v) A beveled corner used on the opening of a hole and the end of a cylindrical part to eliminate sharp corners. Chamfers facilitate the assembly of parts and are specified by giving a linear and angular dimension. When used as a verb, the term refers to the process of creating a chamfer on an object.
(See 337)
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| corner | (n) The nontangential intersection of two or more surfaces of an object. The intersection of two surfaces is usually referred to as an edge. Corners are represented on a drawing by either a single line or multiple co-terminating lines.
(See 332)
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| fillet | (n) A rounded interior corner normally found on cast, forged, or molded parts. Like a round, a fillet can indicate that a surface is not machine finished. A fillet is indicated on engineering drawings as a small arc.
(See 336)
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| fold line | (n) A basic concept in descriptive geometry used to define a line that is perpendicular to projection views of a drawing. A fold line can also describe the “hinge” line between the image planes of the glass box used to define orthographic lines and is shared between multiviews.
(See 307)
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| foreshortened | (adj.) The reduction in size of one or more dimensions of a planar face due to the face not being perpendicular (normal) to the line of sight. The dimension foreshortened is defined by the axis of rotation of the face out of a plane normal to the line of sight. When the face is rotated in its edge view, the foreshortening is applied to a line.
(See 332)
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| frontal plane | (n) A principal orthographic plane of projection. This plane is used to define both the front and back orthographic views.
(See 301)
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| front view | (n) A principal view of an object, typically the first one defined, orienting the object such that the majority of its features will be located in the front, right side, and top views.
(See 307)
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| horizontal plane | (n) A principal orthographic plane of projection, used to define both the top and bottom orthographic views.
(See 329)
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| inclined edge/line | (n) An edge of a face that is parallel to a plane of projection but inclined to the adjacent orthogonal planes. The edge appears as an inclined, true-length line in one of the principal views and is foreshortened in the two adjacent views.
(See 325)
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| left side view | (n) A principal view of an object, created by rotating the viewpoint 90 degrees about the vertical axis to the left of the front view. This view is not typically included in a standard multiview drawing.
(See 307)
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| line of sight (LOS) | (n) Imaginary rays of light radiating from an observer’s eye to the object. In perspective projection, all lines of sight start at a single point; in parallel projection, all lines of sight are parallel. LOS is sometimes referred to as the viewpoint.
(See 299)
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| multiview drawing/sketch | (n) A type of orthographic drawing based on multiview projection techniques in which two or more views of an object are arranged in a single drawing. Each view shows only two dimensions of the object and is chosen to depict specific features of the object clearly and distinctly.
(See 301)
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| multiview projection | (n) A special type of orthographic projection that places the object in a unique position behind a projection plane such that a view is produced that shows only two dimensions of the object. The outline of the features of the part shows where the parallel lines of sight pierce the projection plane.
(See 301)
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| normal edge/line | (n) An edge of a face parallel to a plane of projection and perpendicular to the adjacent orthogonal planes. The edge appears as an orthogonal, true-length line in two of the principal views and as a point in the third view.
(See 325)
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| oblique edge/line | (n) An edge of a face that is not parallel to any of the three primary orthogonal planes. The edge appears foreshortened in all three principal views of a multiview draw-ing.
(See 325)
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| orthographic projection | (n) A parallel projection technique that creates a 2-D image of 3-D objects or structures on an image plane perpendicular to the lines of sight. The orthographic projection technique can produce pictorial drawings, such as isometric or oblique, that show the three dimensions of an object or multiviews that only show two dimensions of an object in a single view.
(See 299)
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| 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.
(See 299)
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| partial view | (n) Aview 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.
(See 349)
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| 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.
(See 299)
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| 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.
(See 299)
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| point | (n) A singular location in space, usually defined by coordinate values (i.e., X,Y,Z).
(See 329)
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| 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.
(See 356)
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| 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.
(See 306)
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| 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.
(See 326)
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| profile plane | (n) A principal orthographic plane of projection. This plane is used to define both the right and left side orthographic views.
(See 302)
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| 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.
(See 299)
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| rear view | (n) Aprincipal 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.
(See 307)
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| 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.
(See 351)
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| 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.
(See 350)
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| 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.
(See 307)
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| round | (n) Around 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.
(See 336)
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| secondary auxiliary view | (n) An auxiliary view projected from a primary auxiliary view. Secondary auxiliary views are used to depict oblique surfaces in their true size and shape.
(See 356)
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| tertiary auxiliary view | (n) An auxiliary view projected from a secondary auxiliary view.
(See 356)
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| top view | (n) A principal view of an object created by rotating the line of sight 90 degrees about the horizontal axis above the front view. This view is typically included in a standard multiview drawing.
(See 307)
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| true-length line | (n) Aline representing an edge that is parallel to a plane of projection and perpendicular to the line of sight.
(See 325)
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2002 McGraw-Hill Higher Education