Drafting standards: why create multiple line widths on technical drawings? In traditional manual drafting and in CAD plotting, why must drafters be able to draw and specify several different line widths on a single drawing sheet?

Introduction / Context:
Engineering graphics uses line conventions to encode meaning visually. Varying line weights (line widths) help readers quickly distinguish object edges from hidden features, centerlines, construction lines, and cutting planes. This is foundational for readability on paper and plotted CAD outputs.

Given Data / Assumptions:

• Drawings contain multiple line types: visible (object) lines, hidden lines, centerlines, dimension lines, and section lines.
• Each line type follows standards (for example, ASME Y14.2) that define both pattern and typical relative weight.
• The purpose is to communicate design intent unambiguously.

Concept / Approach:
Heavier object lines emphasize boundaries and features; medium lines often carry dimensions and leaders; lighter lines indicate secondary references such as construction or hatch lines. By mapping line width to information importance, the drawing remains legible even when reduced or photocopied.

Step-by-Step Solution:

Verification / Alternative check:
Compare against a standard lineweight legend or a sample drawing complying with ASME Y14.2. Readers should distinguish features at a glance.

Why Other Options Are Wrong:

• The darkness alone (option B) is not the core reason; information hierarchy is.
• Fax transmission (option C) is irrelevant in modern CAD workflows and not a drafting principle.
• “It makes no difference” (option D) contradicts drafting standards.

Common Pitfalls:
Using too many distinct weights can clutter the page. Maintain a small, consistent set (for example, heavy, medium, light) and document it in the template.

Final Answer:
different line widths convey different information