Oblique projection principle: In an oblique projection, is one principal face of the object drawn parallel to the picture plane so that it appears in true shape and size while the other dimensions recede at an angle?

Introduction / Context:
Oblique projection is a pictorial method where the front (principal) face of the object is placed parallel to the projection plane, preserving true shape and size. Depth is represented by projecting features along a receding axis at a chosen angle (commonly 30° or 45°) with optional foreshortening (cabinet) to improve realism. This question checks understanding of that core setup.

Given Data / Assumptions:

• The front face is aligned parallel to the picture plane.
• Receding axes represent depth; lengths along them may be full (cavalier) or scaled (cabinet).
• Angles and edges on the front face appear true; edges on receding planes are foreshortened by convention.

Concept / Approach:
Because the front face is parallel to the plane of projection, measurements there transfer directly without distortion. Only depths receding from that face are altered by the chosen oblique convention. This makes oblique useful for quick, dimensionally clear depictions of the front geometry while still suggesting depth.

Step-by-Step Solution:

Verification / Alternative check:
Compare an oblique with an isometric: the front face in oblique remains undistorted; in isometric, all faces are equally foreshortened. This difference confirms the principle.

Why Other Options Are Wrong:
The principle applies to cavalier, cabinet, and general oblique; it does not require a specific angle or a square face.

Common Pitfalls:
Accidentally tilting the front face; applying depth foreshortening inconsistently; mixing isometric and oblique conventions.

Final Answer:
Correct