Different from the general dimensioning, the dimensioning of building height in the architectural drawing is specified to use the elevation symbol.

On the general plan, plan, elevation and section, elevation symbols are often used to indicate the height of a certain part. There are two forms of elevation according to the different elevations of the datum points, namely, absolute elevation and relative elevation. The absolute elevation is the height dimension measured from the mean sea level of the Yellow Sea near Qingdao, China as the zero point. The height of the outdoor floor and road control points in the general plan of the building is generally the absolute elevation, which is accurate to cm in meters.; The relative elevation, also called building elevation, is the elevation that calculates the height with the main ground inside the building as the zero point. The elevation symbols used on various drawings shall be drawn in the form of thin solid lines as shown. The tip of the elevation symbol shall point to the marked height, which can be downward or upward. The elevation value is expressed in meters and is generally noted to three digits after the decimal point (two digits in the general layout). The elevation number in the "Building Construction" drawing represents the value of the finished surface. If there is a "one" in front of the elevation number, it means that the finished surface is lower than the zero point elevation. If there is no sign in front of the number, it indicates that it is higher than the zero point elevation. Lanzhou Project Construction Planning Drawing Design

In the construction drawing, it is sometimes impossible to express a part clearly because of the scale problem, so another detail drawing is needed to facilitate the construction. Generally, index symbols are used to indicate the location of the detail drawing, the number of the detail drawing, and the number of the drawing where the detail drawing is located. The detail number in the callout and detail symbol corresponds to the drawing number. According to the "National Standard", the circle and outgoing line of the index symbol shall be drawn with thin solid lines, and the diameter of the circle is 10mm. The outgoing line shall be aligned with the center of the circle, and a horizontal line shall be drawn across the center of the circle. Arabic numerals shall be used in the upper half circle to indicate the number of the detail drawing, and Arabic numerals shall be used in the lower half circle to indicate the drawing number of the detail drawing. If the detail drawing and the indexed drawing are on the same sheet, draw a horizontal thin solid line in the middle of the lower half circle. If the standard drawing is adopted for the detailed drawing led out by the cable, the number of the standard drawing book shall be marked on the extension line of the horizontal diameter of the index symbol.