Edges and Intersections — Concept Check When a curved surface meets a plane surface on a part, does their intersection create a real edge line that should be represented in orthographic views when it is visible?

Introduction / Context:
Understanding when edges appear is fundamental for reading and creating accurate orthographic drawings. A real edge occurs where two surfaces intersect and form a change in surface orientation. This item asks whether the intersection between a curved surface and a plane surface produces an edge that should be shown on views when visible and not hidden by other geometry. Correct edge representation prevents ambiguity during manufacturing and inspection.

Given Data / Assumptions:

• One surface is curved, such as a cylindrical or spherical region.
• The other surface is planar, such as a machined face.
• Projection is orthographic using standard third angle or first angle conventions.

Concept / Approach:
Edges are loci of points where two surfaces intersect. If the intersection is real, it generates a line in the view where it projects as an outline or visible line. When the intersection is tangent, there is no abrupt change of surface normal, so a true edge line is not drawn. The statement in the stem refers to an intersection, not tangency, therefore a visible edge is correct when the line is in view and not obscured.

Step-by-Step Solution:
1) Determine whether the two surfaces actually intersect rather than merely touch tangentially.2) If they intersect, identify the curve of intersection and its projection in each principal view.3) Draw the edge as a visible line where not hidden; use hidden lines where appropriate.4) Omit edge lines at purely tangent transitions, replacing them with smooth contours only.

Verification / Alternative check:
Compare with standard drafting rules: real intersections create edges; tangencies do not. Section views and auxiliary views confirm the presence and shape of the edge when needed.

Why Other Options Are Wrong:
Incorrect denies true intersections. Partially correct and Only in section views add limits that do not apply. Only if dimensioned confuses representation with annotation.

Common Pitfalls:
Mistaking tangency for intersection; drawing edges where a fillet actually blends surfaces instead of forming a sharp intersection.

Final Answer:
Correct