Line/P,Atangl
Line Through Point at Angle
Creates a line through a point at a specified angle from the positive X axis. No selector needed.
What It Does
The Line/P,Atangl operator creates a line passing through a point at a specified angle from the positive X axis. The angle is measured counterclockwise.
Syntax
Line/P1, Atangl, A
Quick Input
P: [point reference]
Angle: [angle in degrees from +X axis, CCW]
Direction Selector
No direction selector is required. The result is uniquely determined by the input geometry.
Worked Examples
Setup:
P0 = (30, 40)
Line/P0, Atangl, 45
→ L0: through (30,40) at 45°, slope=1
Line/P0, Atangl, 0
→ L1: horizontal through (30,40), Y=40
Line/P0, Atangl, 90
→ L2: vertical through (30,40), X=30
Line/P0, Atangl, 135
→ L3: through (30,40) at 135°, slope=-1
Analytic Rule
Direction vector: (cos A, sin A)
Line equation: y - py = tan(A) * (x - px)
For A=90° (vertical): x = px
For A=0° (horizontal): y = py
0° = horizontal right
90° = vertical up
180° = horizontal left
270° = vertical down
Result: Exact analytic line.
FAQ
How is the angle measured?
Angles are measured from the positive X axis, counterclockwise. 0° is horizontal right. 90° is vertical up. 180° is horizontal left. 270° is vertical down.
Can I use negative angles?
Yes. Negative angles are measured clockwise. -45° is equivalent to 315°.