Hidden line
A line of short, even dashes: an edge or feature that is there but can't be seen in this view.
Easily confused with
How to read it
The Navy's blueprint reading course draws hidden edge lines with short dashes to show hidden features of an object. The A/E/C Graphics Standard uses hidden lines for the hidden features of a part or object.
Also searched as: dashed line, hidden object line.
This explains what a symbol represents on a drawing. Conventions vary between firms and standards, and a drawing's own legend takes precedence.
Look-alikes
A centerline alternates long and short dashes.
Read next
- Next in Blueprint symbolsBreak lineShows that part of the object has been left out of the drawing, usually to fit something long on the sheet.
- The same shape in Weather map symbolsCold front symbolA cold front: the leading edge of colder air pushing into warmer air. On a weather map it is a blue line with blue triangles, and the triangles point the way the front is moving.
More blueprint symbols
The same shape elsewhere
Browse symbols drawn with lines.
Sources
- A/E/C Graphics Standard, Release 2.2, ERDC/ITL SR-23-1, U.S. Army Engineer Research and Development Center, CAD/BIM Technology Center, sec. 4.3
- Blueprint Reading and Sketching, NAVEDTRA 14040A, Naval Education and Training Command, U.S. Navy, ch. 2, hidden lines
- Blue Print Reading: Interpreting Working Drawings, E. M. Wyatt, 1920, Bruce Publishing Company, Milwaukee (Internet Archive), Lines
Researched, edited and approved by Rory Hansen before publishing. Last reviewed September 24, 2026. How we research
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