Projection of circles claim check: If a circle lies in a plane that is not parallel to the plane of projection, does it still project as a circle (unchanged shape) in that view?

Introduction / Context:This question tests the same geometric principle from the opposite angle. When a circular feature sits on a plane inclined to the view, its appearance is altered by projection. Understanding this prevents drawing errors and misdimensioning of holes and round pockets on slanted faces.

Given Data / Assumptions:

• A circle exists on a plane not parallel to the projection plane.
• We are using standard parallel projection, not an auxiliary view aligned to the feature plane.
• No correction (like an auxiliary view) is applied.

Concept / Approach:The circle will appear as an ellipse due to foreshortening along one axis. The only situation in which a circle appears as a true circle in a given view is when the circle’s plane is parallel to the projection plane. Otherwise, the locus of projected points forms an ellipse in that view.

Step-by-Step Solution:

Verification / Alternative check:Compare a tilted washer drawn in front, top, and an auxiliary view: only the auxiliary view parallel to the washer shows a perfect circle; the others show ellipses.

Why Other Options Are Wrong:

Common Pitfalls:Placing a diameter symbol on an ellipse in a nonparallel view without providing an auxiliary true-shape view; assuming the visual circle remains unchanged regardless of orientation.

Final Answer:Incorrect