Engineering Drawing PDF

# ENGINEERING Drawing Reviewer ## Terms and Definitions ### **Projection Line** An imaginary line that is used to locate or project the corners, edges, and features of the 3-dimensional objects onto an imaginary 2-dimensional surface. ### **Hidden Line** A line that is used to represent an edge t...

# ENGINEERING Drawing Reviewer ## Terms and Definitions ### **Projection Line** An imaginary line that is used to locate or project the corners, edges, and features of the 3-dimensional objects onto an imaginary 2-dimensional surface. ### **Hidden Line** A line that is used to represent an edge that is not directly visible. ### **Innovation** An improvement of an existing technological product, system, or method of doing something. ### **Invention** A new product, system, or process that has never existed before, created by study and experiments. ### **Dimension Line** A line which represents distance. ### **Leader Line** Line which indicates dimensions of arcs, circles, and detail. ### **Long-Break Line** A line which indicates that a very long object with uniform detail is drawn foreshortened. ### **Object Line** A heavy solid line used on a drawing to represent the outline of an object. ### **Projection Line** An imaginary line that is used to locate or project the corners, edges, and features of the 3-dimensional objects onto an imaginary 2-dimensional surface. ### **Hidden Line** A line that is used to represent an edge that is not directly visible. ### **Center Line** A line which defines the center of arcs, circles, or symmetrical parts. ### **Scale** Refers to the ratio of an object in a drawing to the size of the true object. The scale factor is the ratio of the size of a drawn object to its real size. A diagram shows a triangle labelled A with sides of 8 cm, 6 cm and 10 cm. A second triangle labelled B with sides of 12 cm, 10 cm and 15 cm. A red curved arrow with x15 points from the smaller triangle to the larger triangle. ### **Proportional** Having the proper size in relation to other objects or items. 1/4 = 3/12 ### **Multiview Drawing** A drawing which contains views of an object projected onto two or more orthographic planes, also orthographic projection. ### **Oblique Sketching** A form of pictorial in which an object is represented as true width and height but depth can be any size and drawn at any angle. ### **Orthographic Projection** A method of representing 3-dimensional objects on a plane having only length and width, right angle projection. ### **Prototype** A full-scale working model used to test a design concept by making actual observations and necessary adjustments. ### **Isometric Drawing** A drawing showing the front, top, and sides of an object, just as the eye sees them. All vertical lines are drawn vertically, but all horizontal lines are drawn at 30 degrees to the horizontal. Engineers can communicate the measurements of an object through an isometric drawing. A diagram shows a 3D box drawn isometrically with the width line at 30 degrees to the horizontal. ### **Orthographic Drawings** Orthographic drawings show the top, sides and bottom of an object, which is why they are also called multi-view drawings. A diagram shows a drawing of a 3D part with separate top, front and right side views. ### **Perspective Drawing** A form of pictorial drawing in which vanishing points are used to provide the depth and distortion that is seen with the human eye. ### **Orthographic Projection** Shows multiple images of a 3-dimensional part in 2 dimensions. Has a front view, plan view and end view. ### **Isometric Drawing** A 2-dimensional drawing of a 3-dimensional part using angles of 30 degrees to the horizontal over 3 axis. ### **Oblique Drawing** A 2-dimensional drawing of a 3-dimensional part using angles of 50 degrees to the horizontal. Front view is shown square on other dimensions are shown at half the original. ### **Extension Line** A thin dark line extending from an object that shows the limits of a dimension line. ### **Center Line** A thin dark line that indicates the center of a circle or arc and the center of a cylinder. ### **Cutting Plane Line** A thick dark line (thicker than the object line) that indicates where an object is cut in half to show the inside of the object. ### **Section Line** A thin dark line with arrowheads on each end that indicates the direction and size of an object or feature on an object. ### **Hard Pencil** Used in mechanical drawing for charts, diagrams and other drawing requiring a high degree of accuracy. ### **Medium Pencil** Used for general purposes such as lettering. ### **Soft Pencil** Used for art works and various kinds. ### **Different Types of Pencil Points** * Colonical * Elliptical * Chisel ### **Section Line** Thin light lines usually drawn at 45 degrees to indicate the surface that has been cut open and exposed. ### **Short Break Line** A wiggly line the same darkness and thickness as an object line that is used to indicate that a smaller object is only partially drawn. ### **Long Break Line** A thick dark line with spikes used to indicate a large or long object is only partially drawn. ### **Phantom Line** Light thin lines with one long and two short dashed alternately spaced that indicate different positions of moving parts. ### **Projection Line** An imaginary line that is used to locate or project the corners, edges, and features of the 3-dimensional objects onto an imaginary 2-dimensional surface. ### **Hidden Line** A line that is used to represent an edge that is not directly visible.