add differential_line_growth_bowl

examples/differential_line_growth_bowl.scad

@@ -0,0 +1,28 @@
+use <shape_circle.scad>;
+use <midpt_smooth.scad>;
+use <polyline_join.scad>;
+use <polyhedra/icosahedron.scad>;
+use <experimental/differential_line_growth.scad>;
+use <experimental/ptf_c2sphere.scad>;
+
+$fn = 24;
+r = 10;
+times = 50;
+line_r = 2;
+smooth = true;
+smooth_times = 2;
+node_option = [
+    0.4,    // maxForce 
+    0.5,    // maxSpeed
+    5,      // separationDistance
+    1.2,    // separationCohesionRatio 
+    4       // maxEdgeLength
+];
+
+init_shape = shape_circle(r);
+poly = differential_line_growth(init_shape, node_option, times);
+smoothed = smooth ? midpt_smooth(poly, smooth_times, true) : poly;
+
+sphere_r = max(max(smoothed));
+polyline_join([for(p = [each smoothed, smoothed[0]]) ptf_c2sphere(p, sphere_r)])
+    icosahedron(line_r);