How must dimensions be drawn in engineering diagrams?

In engineering diagrams, dimensions are typically drawn using a specific set of conventions to ensure clarity and accuracy in communicating measurements. The correct approach involves using arrows to indicate the extent of the dimension, accompanied by extension lines that point to the relevant features. These extension lines are usually drawn so that they do not touch the edges of the drawing itself, maintaining a clear space which enhances readability.

This method allows anyone reviewing the diagram to easily interpret the dimensional information being presented. The presence of color in the arrowheads, while not always required, can help to distinguish the dimensioning from other elements of the diagram, making it visually clear. This adherence to standard dimensioning practices is crucial for efficient engineering communication and prevents misinterpretation of vital measurements.

In contrast, other methods described, such as using solid lines without arrows or relying solely on dotted lines, do not meet the accepted conventions for clear dimension representation in engineering drawing. Similarly, thick lines for emphasis can detract from the clarity needed for dimensioning and are generally not used in the representation of dimensions themselves.