Engineers use cutting plane lines on the plans they are drawing up to differentiate what is inside an object and what lies outside it. The cutting plane line bisects the object and provides a view of its interior features. Cutting plane lines and the interior features of the object they bisect are never in the same color as the rest of the plan.
How cutting plane lines are created
Engineers may manually draw cutting plane lines on their designs by using paper, pencil or pen, a straight edge ruler, or T-Squares. Today, most cutting plane lines are done electronically, with engineers using computer aided design to create them.
How cutting plane lines look
Cutting plane lines are thick lines that run through the center of the object that the interior wants to provide an interior view of. Two perpendicular lines with arrows showing in which direction the interior of the object should be viewed are drawn at the end of the line.
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Forms of cutting plane lines
In the field of engineering, two forms of cutting plane lines have been approved for use on plans. A series of evenly spaced dashes with arrows at the end comprises the first approved form. In the second form, pairs of long dashes are alternated with short dashes to form a cutting plane line.
High density plans
On engineering plans that feature a lot of lines, cutting plane lines can be changed by removing the dashes at either end.