Angle

The angle command measures the interior angle at a vertex formed by two line segments through three clicked points. The result — always between 0° and 180° — is displayed in the terminal to 4 decimal places. It is one of two measurement commands — Distance measures straight-line length instead.

Anatomy of an angle measurement

  ● first point (end of first ray)
   \
    \  first ray preview
     \
      ● vertex (step 3)
     /
    /  second ray preview (to cursor)
   /
  ● third point  →  terminal: "Angle: 45.0000°"

• First point — one end of the angle (step 2).
• Vertex — the corner at which the angle is measured (step 3).
• Third point — the other end of the angle (step 4).

Measuring an angle

1. Type angle in the terminal or click the Angle toolbar button.
2. Click the first point — one arm end of the angle. Or type X,Y and press Enter for an exact coordinate.
3. Click the vertex — the corner where the two arms meet. Coordinate entry works here too.
4. Click the third point — the second arm end. Coordinate entry works here too. Placing this point prints the result.
5. Click again (optional) to start a new measurement from that click as the new first point.

Interior angle convention

The command computes the angle using the dot product of the two rays from the vertex:

• Always interior: the result is the smaller angle, between 0° and 180°.
• The order you click the end points does not affect the result — only the vertex position matters.
• Collinear points (all three on one line) return 0° or 180°.

Chaining measurements

After the result appears, clicking immediately starts the next measurement — the clicked point becomes the new first point. The command never auto-exits until you press Escape.

Angle vs Distance

	Angle	Distance
What it measures	Interior angle at a vertex	Straight-line length
Number of clicks	3	2
Result format	45.0000°	12.3456 (units)
Canvas preview	Two lines from vertex to both ends	Line from first point to cursor
Best for	Opening angle between two features	Length of a gap or segment

Coordinate entry

Instead of clicking, type an exact position for any of the three points:

1. Type the X value.
2. Press , — the terminal shows [X], [Y{cursor}].
3. Type the Y value.
4. Press Enter to confirm.

Keyboard reference

Key	Action
0–9, ., -	Start X coordinate entry
,	Lock X and move to Y entry
Backspace	Delete last typed character
Enter	Confirm typed coordinate
Escape	Cancel and reset to step 2

Notes

• Results are shown in the terminal only — nothing is added to the drawing.
• Precision is always 4 decimal places in degrees.