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PowerPoint Presentation. Publisher The Goodheart-Willcox Co., Inc. Tinley Park, Illinois. Chapter 4. Drawing Instruments and Techniques. Orthographic Projection. Orthographic projection is the most basic drafting technique.
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PowerPointPresentation PublisherThe Goodheart-Willcox Co., Inc.Tinley Park, Illinois 1
Chapter 4 Drawing Instruments and Techniques 2
Orthographic Projection • Orthographic projection is the most basic drafting technique. • A means of representing the height, width, and depth of a three-dimensional object on two-dimensional paper. • The object is viewed at infinity, thus projection lines are parallel to each other. • Typically, three views are used. 3
Orthographic Projection • This camp cottage shows the arrangement of views in orthographic projection. 4
Three Principal Views • The three principal views in orthographic projection are the top, front, and right side views. • In architectural drafting, the views are similar but have different names. • The top view of a house is called a planview; used as the basis for most other drawings. (continued) 5
Three Principal Views • The floor plan is a top view in section taken about half way up the wall. • The front elevation in architectural drafting is the same as the front view in mechanical drafting. • Architectural drafters ordinarily draw a view of each side of the structure, which are called elevations. 6
Three Principal Views • How orthographic views are projected. 7
Border Lines Object Lines Hidden Lines Centerlines Extension Lines Dimension Lines Long Break Lines Short Break Lines Cutting-Plane Lines Section Lines Guidelines Construction Lines Architectural Alphabet of Lines 8
Border Lines • Border lines are very heavy lines used to form a boundary for the drawing. • Use a 0.70mm pen. 9
Object Lines • Object lines are heavy lines that outline features of an object. • Use a 0.50mm pen. 10
Hidden Lines • Hidden lines represent edges that are behind a visible surface in a given view. • Use a 0.35mm pen. 11
Centerlines • Centerlines indicate the center of holes and symmetrical objects, such as windows and doors. • Use a 0.25mm pen. 12
Extension Lines • Extension lines are used to denote the termination points of a dimension line. • Use a 0.25mm pen. Extension lines 13
Dimension Lines • Dimension lines are used to show size and location. They have a dimension figure halfway between the ends of the dimension line. • Use a 0.25mm pen. 14
Long Break Lines • Long break lines are used to show that not all of the part is shown. • Use a 0.25mm pen. 15
Short Break Lines • Short break lines show part of the object broken away. • Use a 0.70mm pen. 16
Cutting-Plane Lines • Cutting-plane lines are used to show where the object is sectioned. • Use a 0.70mm pen. 17
Section (Crosshatch) Lines • Section lines or crosshatch lines are used to show that a feature is sectioned. • May represent different types of material. • Use a 0.25mm pen. 18
Guidelines • Guidelines are used in hand lettering to keep lettering straight. • Very light lines. • Drawn in pencil only. 19
Construction Lines • Construction lines are used in the process of constructing a drawing. • Should not be reproduced. • Not inked or plotted. 20
Line Type Application • In manual drafting, all lines are black and vary only in width. Colors may be used in CADD. 21
Architectural Lettering • There is no single style of architectural lettering. Most lean toward the artistic. • Develop your own style. 22
Developing a Lettering Style • Words should not appear to run together or be too far apart. • Space between words should usually equal the height of an uppercase letter. • Most information lettered on a drawing is 1/8" or 3/32" high. • Try making the first letter in each word 1/8" and the remainder 3/32" high. (continued) 23
