Alphabet of Lines Application and Description Visible Object

Alphabet of Lines Application and Description

Visible Object Lines are drawn to represent the edges of an object.

Hidden Lines are drawn to represent edges that are inside or hidden from view.

Center Lines are drawn to show the center of holes and the center of symmetrical objects.

Dimension Text Dimension Line Extension Line Dimension Text illustrates the actual size of an object. Dimension Line with arrow heads are drawn the length of the dimension. Extension Lines are drawn from the edges of the object that represent the dimension.

Leader Text Leader Line Diameter Symbol Leader Line drawn with arrowhead pointing to the center of the circle. Leader Symbol for diameter (O with a slash through the center). Leader Text completes the dimension for the diameter of the cylinder.

Cutting Plane Line Section Lines Cutting Plane Line is drawn to represent an imaginary cut into an objects surface. Section Lines are drawn to represent the inside surface of the imaginary cut into the object.

Short Break Lines are drawn with freehand or irregular lines to represent breaks for detailing surfaces.

Long Break Lines are used when it is best to shorten the long view of an object.

Phantom Lines are drawn to represent alternate positions of a moving part.