functions for plotting arcs in SCAD

array<array<x,y>> arc(x, y, from, to, [radius], [diameter], [$fn], [$fa], [$fs])

x	number	The center x point of the arc
y	number	The center y point of the arc
from	number	The starting angle of the arc
to	number	The ending angle of the arc
radius	number	(optional) The radius of the arc
diameter	number	(optional) The diameter of the arc
$fn	number	(optional) The number of segments of the arc
$fa	number	(optional) The angle the arc will be segmented by
$fs	number	(optional) The magnitude the arc will be segmented by
returns	array<array<number, number>>	Returns the collection of 2d points for the arc

x, y, from, to and either radius or diameter are required. The default segment setting is $fs=1.

// Draws a 90 degree pie slice starting at 45 degrees
polygon(points = concat(
  [[0,0]], // center point
  arc(0,0,45,135,radius=50)
));

// Draws a square with rounded corners
size = 20;
corner = 5;
polygon(points = concat(
  arc(corner,corner,-90,-180,radius=corner), // lower-left corner
  arc(size-corner,corner,180,90,radius=corner), // lower-right corner
  arc(size-corner,size-corner,90,0,radius=corner), // upper-right corner
  arc(corner,size-corner,0,-90,radius=corner) // upper-left corner
));

// Compares two arcs set to $fn=5 (i.e. 5 "total" segments)
polygon(points = concat(
    [[0,0]],
    arc(0,0,0,90,20,$fn=5)
));
        
polygon(points = concat(
    [[30,0]],
    arc(30,0,0,90,40,$fn=5)
));

// Compares two arcs set to $fa=5 (i.e. segment per 5 degrees)
polygon(points = concat(
    [[0,0]],
    arc(0,0,0,90,20,$fa=5)
));
        
polygon(points = concat(
    [[30,0]],
    arc(30,0,0,90,40,$fa=5)
));

// Compares two arcs set to $fs=5 (i.e. segment per 5mm)
polygon(points = concat(
    [[0,0]],
    arc(0,0,0,90,20,$fs=5)
));
        
polygon(points = concat(
    [[30,0]],
    arc(30,0,0,90,40,$fs=5)
));