Alphabet and Symbolic Lines

It is the thickest line that encloses the entire illustration.

• Borderline

• Visible line

• Hidden line

It is the line that clearly defines the drawing that can be seen by the observer’s eye. They are made up by of heavy strokes of soft pencil.

• Borderline

• Visible line

• Hidden line

It represents the part of the drawing that is not visible to the observer’s eye but needs to be detailed to describe dimension. These lines are composed of short dashes drawn in 1-2 millimeters gap.

• Extension or projection line

• Hidden line

• Dimension line

It shows the limit of the dimension that are extended from the drawing in about 1-2 millimeters gap.

• Dimension line

• Extension or projection line

• Leader line

It is drawn between extension lines to describe the measurement of the object being projected. This line is composed of arrows at both ends and the unit measure

situated at the middle of the line.

• Leader line

• Reference line

• Dimension line

It can be both used for indicating measurement and labeling or describing part of the object. It is made up of horizontal and slanted lines with an arrowhead at one end.

• Reference line

• Leader line

• Dimension line

It is an alternative to leader line, may be used to describe the portion of the object. This is an irregular curve line with arrowhead at one end.

• Dimension line

• Reference line

• Hidden line

This light line identifies the axis of the symmetrical object. Long and short dashes are drawn alternately for about 1-2 millimeters distance.

• Center line

• Break lines

• Cutting plane line

These lines are used to indicate part of the drawing that is

continuous but too long to illustrate.

• Break lines

• Cutting plane line

• Section line

It illustrates portion of the imaginary object where cutting took place. The symbolic line is made up of long dash and two short dashes drawn repeatedly, followed by the vertical dash and arrowhead on both ends.

• Section line

• Phantom line

• Cutting plane line