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Alphabet of Lines
Alphabet of Lines
In the language of drafting, there is an alphabet of lines. Each line type used has a different meaning to make the drawing easier to understand. It is essential to know the alphabet of lines even for drafting done with CAD. Notice the various thicknesses and styles.
"Alphabet of Lines." Explore Drafting, by John Walker and Bernard Mathis, Goodheart-Wilcox Company, Inc, 2007 p. 44.
Below is the meaning of each line type in order of the frequency with which we will use them.
Object Line - Used to represent visible edges and boundaries
Hidden Line - Represent edges and boundaries that are not visible from the viewing direction (holes or cut outs)
Center Line - Represent an axis of symmetry for a rounded feature
Dimension Line - Used to show the size of an object
Extension Line - Used to show the location of an object; extends from the dimension lines
Construction Line - Used to help set up a drawing, but not shown in the final print
Border Line - Used to draw the border of the drawing layout; the thickest lines used in technical drawing
Cutting-plane Line - Represent where a "cut" has been made to show the interior of the object
Section Line - Used to indicate an interior of an object that have been exposed from a cutting-plane line
Phantom Line - Represent alternate positions of a moving part
Guideline - Used to keep writing in a straight line of uniform height (not necessary in CAD)
William Anderson (Schoolworkhelper Editorial Team), "TECHNICAL DRAWING & ALPHABET OF LINE," in SchoolWorkHelper, 2021, https://schoolworkhelper.net/technical-drawing-alphabet-of-line/.
Practice
Practice
Complete THIS INTERACTIVE to see how each of the lines are used in practice.
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