Crossing lines rule: When extension lines or centerlines cross visible object lines, should they remain continuous (no gaps left in the visible lines)?

Introduction / Context:
Line conventions establish how different line types interact on a drawing. Visible (object) lines, hidden lines, centerlines, and dimension/extension lines each convey different information. A frequent scenario is an extension or centerline crossing a visible edge. Knowing whether to gap or continue the lines preserves legibility and adherence to standards.

Given Data / Assumptions:

• Standard mechanical drafting per common ASME/ISO practices.
• Visible lines are continuous and typically heavier than center or extension lines.
• No special local rule to force breaking object lines at crossings.

Concept / Approach:
Visible lines define the real edges of an object. Extension lines and centerlines are auxiliary indicators for dimensions and axes. When line types cross, the general convention is not to break the visible line. Instead, allow the thinner extension or centerline to pass through, relying on line weight hierarchy (object lines heavier) for visual precedence.

Step-by-Step Solution:

Verification / Alternative check:
Reference typical standard plates: intersections remain continuous, leveraging line weights—not breaks—to convey hierarchy. This increases clarity and prevents misreading.

Why Other Options Are Wrong:

Common Pitfalls:
Overusing breaks to reduce clutter; drawing extension lines too heavy so they visually compete with object lines.

Final Answer:
Correct