Assess the claim: “Auxiliary views allow principal faces that are already parallel to the standard planes of projection to appear in true shape and size.” Decide if this is correct.

Introduction / Context:
True shape and size in orthographic projection occur when a face is parallel to the projection plane. Standard (principal) views already show faces parallel to their respective planes in true shape. Auxiliary views are introduced primarily for faces that are inclined or oblique, not already parallel. We evaluate the statement accordingly.

Given Data / Assumptions:

• Principal planes: front, top, side.
• A face parallel to a principal plane appears in true shape on the corresponding principal view.
• Auxiliaries are intended to correct foreshortening on non-parallel faces.

Concept / Approach:
If a face is parallel to, say, the frontal plane, the front view displays its true shape and no auxiliary is needed. Auxiliaries are reserved for inclined/oblique faces where standard views show foreshortening and cannot supply accurate shape for dimensioning and inspection.

Step-by-Step Solution:
1) Check orientation of the target face relative to principal planes.2) If parallel, read true shape directly in the matching principal view.3) If inclined/oblique, construct an auxiliary aligned to the face.4) Use the auxiliary to recover undistorted geometry for features on that face.

Verification / Alternative check:
Compare a rectangular plate parallel to the front plane: front view shows a true rectangle already, while an inclined plate needs an auxiliary to eliminate foreshortening.

Why Other Options Are Wrong:
“Correct”: Misunderstands when auxiliaries are needed.“Only needed for parallel faces on profiles” / “Always required”: Both contradict the role of principal views and misuse auxiliaries.

Common Pitfalls:
Creating unnecessary auxiliaries for geometry already in true shape; forgetting that auxiliaries add complexity and should be used when justified.

Final Answer:
Incorrect