Section lining convention: Are ribs, webs, gear teeth, and similar thin features typically left unhatched when the cutting plane passes longitudinally through them?

Introduction / Context:
Section views clarify interior detail by showing material cut by a hypothetical cutting plane with hatch (section) lines. However, some features—such as ribs, webs, and gear teeth—follow special conventions to avoid miscommunication of thickness or strength.

Given Data / Assumptions:

• The cutting plane passes lengthwise (longitudinally) through thin plate-like features.
• Standard mechanical drafting conventions are assumed.
• Goal is to represent design intent clearly without implying unintended bulk.

Concept / Approach:
Hatching thin reinforcing elements when cut lengthwise can make them appear thicker or “solid,” misleading readers about their function. To prevent this, drafting standards specify that ribs, webs, spoke arms, and gear teeth are often left unhatched in longitudinal sections; the outline conveys their presence while avoiding false emphasis on thickness.

Step-by-Step Solution:

Verification / Alternative check:
Compare two drawings of a flanged bracket with a rib: one hatched, one unhatched across the rib. The unhatched convention communicates a thin stiffener better and avoids overstatement of mass.

Why Other Options Are Wrong:

Common Pitfalls:
Hatching ribs in longitudinal section, confusing viewers; forgetting to show a slight space between hatch and boundary to maintain clarity.

Final Answer:
Correct