Edges on Contoured Surfaces — Representation Rule If a plane cuts a contoured surface on a part, should a line representing their real intersection be drawn on the view when it is visible, rather than omitting any edge entirely?

Introduction / Context:
Readers rely on edge lines to understand where surfaces meet. The statement claims that when a plane intersects a contoured surface, no line is drawn. That is contrary to standard practice. When a true intersection exists, its projection is represented as an edge in visible or hidden form as appropriate. Omitting the line would conceal important geometry and can lead to misinterpretation in manufacturing and inspection.

Given Data / Assumptions:

• The plane truly intersects, rather than merely touching tangentially.
• Orthographic projection rules for visible and hidden lines apply.
• No fillet is blending away the abrupt change of surface orientation.

Concept / Approach:
A line appears in the view wherever there is a discontinuity in surface direction that projects to the viewer. A real intersection between two surfaces creates such a discontinuity. In contrast, tangency produces no visible edge because the surface normal changes smoothly without a sharp break. Therefore, a plane cutting a contoured surface yields an intersection curve that should be drawn to show the real edge when visible.

Step-by-Step Solution:
1) Confirm that the relationship is intersection, not tangency.2) Determine the shape of the intersection curve and its projection on each view.3) Draw the line as visible where unobstructed and as hidden where occluded.4) If a fillet blends the surfaces, omit a sharp edge and show only the smooth contour.

Verification / Alternative check:
Section views and auxiliary views often reveal the intersection directly and justify the corresponding edge representation on principal views.

Why Other Options Are Wrong:
Correct would endorse omitting a true edge. The other distractors restrict a general rule without justification because edges are drawn regardless of whether they are dimensioned or only in auxiliary views.

Common Pitfalls:
Drawing edges for tangent contacts; failing to update hidden lines when visibility changes due to viewpoint or additional features.

Final Answer:
Incorrect