Surface orientation in projection: a surface that is tipped relative to all three principal planes (horizontal, frontal, and profile) does not appear in true size in any standard multiview. Such a surface is classified as which type?

Introduction / Context:
Surface classification—parallel, perpendicular, inclined, and oblique—determines how a surface appears in different orthographic views. Oblique surfaces are the most visually deceptive because they foreshorten in all principal views.

Given Data / Assumptions:

• The surface is tipped to all principal planes.
• We are considering standard multiview projections.
• No auxiliary view has been created to show true shape.

Concept / Approach:
A surface parallel to a plane shows true size in that view; perpendicular appears as an edge; inclined is parallel to one plane and inclined to another; oblique is inclined to all three principal planes and thus never appears true size in any of the standard views.

Step-by-Step Solution:

Verification / Alternative check:
Create an auxiliary view perpendicular to the oblique surface; only then will the true size be obtained, confirming that standard views do not show it true.

Why Other Options Are Wrong:

• Foreshortened: a result/appearance, not a classification; many surfaces can appear foreshortened.
• Parallel/Orthographic: “parallel” is an orientation to a plane; “orthographic” refers to the projection method, not surface type.

Common Pitfalls:
Using “foreshortened” as a type rather than an appearance; the correct classification is “oblique.”

Final Answer:
Oblique