Placement of dimension text Is it acceptable to letter (place) a dimension value over any line on the drawing, including object and extension lines?

Introduction / Context:
Dimension legibility is critical for unambiguous interpretation. Standards require that dimension text be clear of other lines and symbols so it can be read without confusion. Crowding text over object or extension lines can hide details or cause misreads, which in turn lead to manufacturing errors.

Given Data / Assumptions:

• Dimension lines, extension lines, and object lines are present.
• There is enough space to place text properly, or the layout can be adjusted.
• Readability and clarity take precedence over compactness.

Concept / Approach:
Dimension values should sit above (or break) the dimension line and be free from interference with other geometry. If space is tight, relocate or stagger dimensions, use jogs, or use an alternate view so that the number does not cross other lines. This keeps the reading order predictable and prevents accidental masking of edges.

Step-by-Step Solution:

Verification / Alternative check:
Print or plot a check copy at intended scale to ensure all values are legible and not visually merged with geometry.

Why Other Options Are Wrong:
“Correct” contradicts dimensioning best practices. Allowing overlap based on drawing size, lineweight, or tolerance criticality does not fix the readability problem.

Common Pitfalls:
Allowing CAD auto-placement to stack text over lines, failing to break the dimension line for text when required, or leaving text too close to arrowheads.

Final Answer:
Incorrect