Arc/Circle,Tanto,L,L

Arc from Circle Tangent to Two Lines

Creates an arc from a reference circle tangent to two lines. Specify the two lines, the circle, number of points, arc direction (CW/CCW), and trim options for each line. Lines are automatically trimmed to the arc tangent points.

What It Does

The Arc/Circle,Tanto,L,L operator creates an arc from a reference circle that is tangent to two specified lines. The arc spans between the two tangent points on the lines. The CW/CCW selector specifies the sweep direction. Each line can be automatically trimmed to the tangent point using the L1 Trim and L2 Trim options.

Automatic trim: When Trim is set to Auto, each line is automatically trimmed to the arc tangent point — no separate Trim operation needed.

Syntax

Arc/Circle,Tanto,L,L

Quick Input

L: 0
L2: 1
C: 0
Pts: 64
Arc Dir: CCW CW
L1 Trim: Auto Start End
L2 Trim: Auto Start End

Direction Selector

Field	Options	Effect
`Arc Dir`	CW / CCW	Clockwise or counter-clockwise sweep of the arc
`L1 Trim`	Auto / Start / End	Auto trims L1 to the tangent point automatically; Start/End trims at that endpoint
`L2 Trim`	Auto / Start / End	Auto trims L2 to the tangent point automatically; Start/End trims at that endpoint

Worked Examples

Setup:
  L13: vertical line at X=-20  (start -20,-200  end -20,200)
  L14: vertical line at X=+20  (start  20,-200  end  20,200)
  C4:  circle centre (0,0), r=20

Arc/Circle,Tanto,L,L
  L: 13  L2: 14  C: 4  Pts: 64
  Arc Dir: CCW
  L1 Trim: Auto  L2 Trim: Auto

→ A6: start (-20, 0)  end (20, 0)
       Start angle: 180°  End angle: 0°
       Sweep: 180° CCW

→ L15: trimmed — start (-20, 200)  end (-20, 0)
→ L16: trimmed — start  (20, 200)  end  (20, 0)

Analytic Rule

Arc is taken from reference circle C.
Tangent points computed where C touches L1 and L2.
Arc sweeps between tangent points in chosen direction.
L1 and L2 trimmed to tangent points (Auto mode).

Result: Exact analytic arc from circle tangent to two lines.

FAQ

Do I need a separate Trim step?

No. When L1 Trim and L2 Trim are set to Auto, both lines are automatically trimmed to the arc tangent points as part of this single operation.

What does Pts control?

Pts sets the number of points used to render the arc on screen. 64 is the standard value for smooth arcs. It does not affect the mathematical accuracy of the arc.

What is the difference between Arc Dir CW and CCW?

CW sweeps the arc clockwise between the two tangent points. CCW sweeps counter-clockwise. Choose the direction that gives the arc shape you need.

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