Angles in isometric projection: In a standard isometric drawing setup, are all horizontal lines drawn at 60 degrees from a reference point, or do standard isometric axes use other angles for the receding directions?

Introduction / Context:
Isometric drawings are based on three axes equally spaced at 120 degrees. On a typical sheet or monitor, this appears as one vertical axis and two axes inclined relative to the horizontal. The statement asserts that all horizontal lines are drawn at 60 degrees, which conflicts with standard practice.

Given Data / Assumptions:

• Standard isometric axes: one vertical, two receding axes at ±30 degrees from the horizontal baseline.
• Edges parallel to an isometric axis are drawn along that axis.
• True “horizontal” edges of the object project along the two ±30-degree axes, not at 60 degrees.

Concept / Approach:
The 120-degree separation between axes translates to ±30 degrees from horizontal for the receding axes. A 60-degree claim confuses complementary angles. While some construction lines inside faces may appear at various angles, the primary isometric “horizontals” (edges along width and depth) are drawn at 30 degrees, not 60.

Step-by-Step Solution:
Establish isometric axes: vertical (Z), and two receding (X and Y) at +30 and -30 degrees.Project object edges parallel to these axes.Note that 60-degree lines would not align with standard isometric directions.Conclude the statement is invalid.

Verification / Alternative check:
Use an angle measure tool in CAD; isometric guides display ±30-degree snaps for receding axes.

Why Other Options Are Wrong:
“Correct” misstates the canonical angles; the other options introduce unrelated conditions and do not correct the geometry.

Common Pitfalls:
Mixing up 30 and 60 degrees; assuming any slanted line equals an isometric axis.

Final Answer:
Incorrect