In AutoCAD-style CAD, will the Extrude tool create a valid 3D result from a 2D profile even if the corners are not closed (i.e., open polyline or sketch)? Clarify solid vs surface.

Introduction / Context:
Extrusion turns 2D profiles into 3D geometry. Whether you obtain a solid or just a surface depends on whether the profile is closed. This question tests if you can distinguish between extruding open versus closed loops in common CAD workflows.

Given Data / Assumptions:

• Extrude acts on 2D entities (polylines, regions).
• Closed loops can generate 3D solids.
• Open curves generally produce surfaces, not solids.

Concept / Approach:
Rule of thumb: closed profile → solid; open profile → surface. If the prompt claims “it will extrude even if corners are not closed” without distinction, it is misleading for solids. We must parse the intent: “create a 3D result” could be true (surface), but presented generically it implies a solid, which is not correct for open loops.

Step-by-Step Solution:

Verification / Alternative check:
Create a rectangle (closed) and extrude: you get a prism (solid). Create an open polyline and extrude: you get a surface. The software explicitly distinguishes result types.

Why Other Options Are Wrong:
“Correct”: ignores solid vs surface difference. “Works only when dynamic UCS is disabled” and “Works only in paper space”: unrelated constraints. “Only for surfaces; solids require a closed profile” is partially explanatory but the question asks a blanket claim; the correct judgment is “Incorrect.”

Common Pitfalls:
Confusing surfaces with solids; assuming any extrude equals a solid; not closing the sketch before extruding for solid modeling tasks.

Final Answer:
Incorrect