Introduction / Context:
Line types are standardized to avoid confusion. The short dashed line is universally recognized as a hidden line, indicating an edge or feature that is not visible in the current view because it lies behind material. Using hidden-line style to represent a visible feature would mislead readers and violate drafting standards.
Given Data / Assumptions:
- Visible outlines should be continuous thick lines.
- Hidden features use short dashes of specified spacing and weight.
- Centerlines are alternating long/short dashes of lighter weight.
Concept / Approach:
The match between meaning and pattern is critical. A dashed pattern means “not seen” in that view; a continuous line means “seen.” Altering that mapping introduces risk: a machinist might remove material incorrectly or overlook a critical feature. Therefore, short dashed lines are not used for visible features.
Step-by-Step Solution:
Determine whether the feature is visible from the current viewpoint.If visible, draw a continuous thick line; if hidden, use the hidden-line dash pattern.For symmetry axes, use a centerline, not a hidden or visible line.For clearer communication, consider adding a section or auxiliary view instead of overusing hidden lines.
Verification / Alternative check:
Cross-check with another orthographic view; a feature visible in one view should not appear as hidden in the same view.
Why Other Options Are Wrong:
Correct: The statement permitting dashed lines for visible edges is incorrect.Allowed only for very small features / Permitted when scale is less than 1:5: Size or scale does not change the fundamental meaning of line types.
Common Pitfalls:
Letting poor plot settings make continuous lines appear broken.Confusing centerlines and hidden lines due to improper dash spacing.
Final Answer:
Incorrect
Discussion & Comments