Technical Drawing — While constructing a freehand sketch of a solid, you should maintain a single consistent viewpoint; switching between multiple viewpoints in the same sketch causes ambiguity.

Introduction / Context:
A freehand sketch is a quick visual to communicate form and features. Clarity depends on a consistent viewer position. Mixing viewpoints within a single sketch can distort relationships and mislead readers.

Given Data / Assumptions:

• Single-viewpoint sketches mimic what a person would see from one position.
• Multiple orthographic views are separate sketches, each with its own viewpoint.
• Goal is readability, not optical tricks.

Concept / Approach:
Consistency of projection ensures edges, faces, and proportions align. If depth cues or axes shift within one image, lengths and angles become confusing, undermining the sketch’s purpose.

Step-by-Step Solution:
1) Choose a viewpoint (e.g., isometric orientation) and stick to it.2) Establish axes and proportion guidelines.3) Add features using the same projection rules.4) Use line weights to emphasize visible edges.

Verification / Alternative check:
Compare two sketches: one with a consistent viewpoint and one with mixed viewpoints. The latter appears distorted and is harder to interpret.

Why Other Options Are Wrong:
Claiming to use “at least two viewpoints at once” or “three viewpoints in one sketch” contradicts drafting convention; pencil hardness has no bearing on viewpoint consistency; calling the statement “Correct” misrepresents best practice.

Common Pitfalls:
Changing axes midway or rotating the object inconsistently confuses readers. Keep construction lines light and orientations stable.

Final Answer:
Incorrect