Question

Which figure is correct regarding the placement of dimensions or notes within the section lines?

(a) 1st

(b) 2nd

(c) 3rd

(d) Both 2nd and 3rd

This question was posed to me in an online quiz.

Question is from Sections of Solids in chapter Orthographic Projection, Projections of Lines, Planes and Solids of Civil Engineering Drawing

Answer 1

Right option is (b) 2nd

Best explanation: General Rules For Dimensioning are as follows:

Dimensions should NOT be duplicated, or the same information be given in two different ways.

No unnecessary dimensions should be used – only those needed to produce or inspect the part.

Dimensions should be placed at finished surfaces or important center lines.

Dimensions should be placed so that it is not necessary for the observer to calculate, scale, or assume any measurement.

Dimensions should be attached to the view that best shows the shape of the feature to be dimensioned.

Avoid dimensioning to hidden lines wherever possible.

Dimensions should not be placed on the object unless that is the only clear option.

Overall dimensions should be placed the greatest distance away from the object so that intermediate dimension can nest closer to the object to avoid crossing extension lines.

A dimension should be attached to only one view (i.e., extension lines should not connect two views).

Never cross dimension lines.

Never cross extension lines.

A center line may be extended and used as an extension line.

Leaders should slope at a 30, 45 or 60 degree angle.

Dimension numbers should be centered between arrowheads, except when using stacked dimensions then the numbers should be staggered.

In general, a circle is dimensioned by its diameter, an arc by its radius.

Holes should be located by their center lines.

Holes should be located in the view that shows the feature as a circle.

Extension lines start approximately 1/16″ from the object and extend 1/8″ past the last Dimension.