AutoCAD and isometric drafting – command behavior clarification: The Offset command in CAD is designed to create parallel copies of selected geometry at a specified distance. Evaluate the statement: “Offset can be applied on vertical lines but not on horizontal lines.” State whether this claim is valid or invalid, keeping in mind that Offset operates on lines of any orientation (vertical, horizontal, or angled).

Introduction / Context:
The Offset command is a fundamental CAD tool used in both 2D drafting and in preparation steps for 3D or isometric drawings. It creates a parallel (or concentric) copy of the selected entity at a user-defined distance. The statement claims Offset works for vertical lines but not for horizontal lines. This item tests your understanding of orientation independence for core CAD operations.

Given Data / Assumptions:

• The Offset command accepts most linear and curvilinear entities (lines, polylines, arcs, circles, etc.).
• Orientation of a line can be vertical, horizontal, or at any angle.
• Drawing aids like ORTHO, SNAP, and OSNAP may affect cursor behavior but do not restrict the Offset function to certain orientations.

Concept / Approach:
Offset is geometric: it constructs a locus parallel to the selected object at a constant perpendicular distance. A line has a well-defined normal direction regardless of whether it is vertical or horizontal. Therefore, the algorithm does not discriminate based on screen or world orientation. If you can select the line, you can offset it.

Step-by-Step Solution:
Invoke Offset and specify a distance d.Select any line—vertical, horizontal, or angled.Indicate the side to place the offset copy.Observe that the result is a parallel line at distance d; orientation does not matter.

Verification / Alternative check:
Repeat the same steps with a horizontal test line; Offset produces an identical-quality parallel entity. Try again with an angled line or an arc to confirm generality.

Why Other Options Are Wrong:
“Correct” contradicts standard CAD behavior. “Applies only to arcs and circles” is incorrect—lines work as well. “Valid only in perspective views” is irrelevant; Offset is a drafting operation. “Works only when ORTHO is on” is false; ORTHO constrains cursor motion, not the Offset computation.

Common Pitfalls:
Confusing Offset with copy-and-rotate or fillet; misattributing cursor constraints to command limitations.

Final Answer:
Incorrect