add arc_great_circle

src/experimental/arc_great_circle.scad

@@ -0,0 +1,12 @@
+use <__comm__/__frags.scad>
+use <ptf/ptf_rotate.scad>
+
+function arc_great_circle(p1, p2, center = [0, 0, 0]) =
+    let(
+        radius = norm(p1 - center),
+        normal_vt = cross(p2, p1),
+        a = acos(p2 * p1 / pow(radius, 2)),
+        steps = round(a / (360 / __frags(radius))),
+        a_step = a / steps
+    )
+    [for(i = [0:steps]) ptf_rotate(p1, a_step * i, normal_vt)];