Section marker
Marks where the drawing is cut through to show a section. The arrow shows the way the section looks; the circle gives the section's number and the sheet it's drawn on.
Easily confused with
How to read it
In the A/E/C Graphics Standard the circle is split in two: the top half identifies the section and the bottom half gives the sheet it is on, and section sheets carry a 3 in the sheet-type position. The Army's print-reading manual describes the cutting plane as short heavy lines with arrowheads showing the viewing direction, with letters such as AA at the arrowheads. The Navy's blueprint reading course says the arrows point the way to look at the section.
Also searched as: building section symbol, section callout, section cut.
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
An elevation marker and a detail callout use the same split circle. The sheet number tells them apart: 2 for elevations, 3 for sections, 5 for details.
Read next
- Next in Blueprint symbolsElevation markerPoints to an elevation, a view of the building's face drawn on the elevations sheet. The circle gives the elevation's number and its sheet.
- The same shape in African flagsFlag of EritreaEritrea’s flag is divided by a red triangle running from the whole pole edge to a point at the fly, with green above and blue below, and a gold olive branch inside a gold wreath on the red. Eritrea’s Ministry of Information explains the green as the country’s fertility, the blue as the sea and the red as the blood lost in the fight for freedom; the wreath’s 30 leaves count the years of the armed struggle.
More blueprint symbols
The same shape elsewhere
Browse symbols drawn with circles, letters and numbers or triangles.
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, secs. 4.2.4.1, 4.2.4.3
- Construction Print Reading in the Field, TM 5-704 / AFM 85-27, Departments of the Army and the Air Force, para. 1-3j
- Blueprint Reading and Sketching, NAVEDTRA 14040A, Naval Education and Training Command, U.S. Navy, ch. 2, viewing or cutting plane lines
Researched, edited and approved by Rory Hansen before publishing. Last reviewed September 24, 2026. How we research
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