add hollow_out_starburst

examples/hollow_out_starburst.scad

@@ -0,0 +1,35 @@
+use <shape_starburst.scad>;
+use <hull_polyline3d.scad>;
+use <experimental/tri_bisectors.scad>;
+
+r1 = 30;
+r2 = 12;
+h = 10;
+n = 5;
+thickness = 1.75;
+half = true;
+
+module hollow_out_starburst(r1, r2, h, n, thickness, half = false) {
+    star = [for(p = shape_starburst(r1, r2, n)) [p[0], p[1], 0]];
+    leng = len(star);
+    tris = concat(
+        [for(i = [0:leng - 2]) [[0, 0, h], star[i], star[i + 1]]],
+        [[[0, 0, h], star[leng - 1], star[0]]]
+    );
+    
+    module half_star() {
+        for(tri = tris) {
+            hull_polyline3d(concat(tri, [tri[0]]), thickness = thickness);
+            for(line = tri_bisectors(tri)) {
+                hull_polyline3d(concat(line, [line[0]]), thickness = thickness);
+            }
+        }    
+    }
+    
+    half_star();
+    if(!half) {
+        mirror([0, 0, 1]) half_star();
+    }
+}
+
+hollow_out_starburst(r1, r2, h, n, thickness, half);