change dir

examples/spiral_polygons/square_pursuit_3d.scad

@@ -0,0 +1,44 @@
+use <hull_polyline3d.scad>;
+
+length = 100;
+diff_scale = 0.125;
+diameter = 2;
+n = 30;
+$fn = 6;
+
+module square_pursuit_3d(length, diff_scale, diameter, n) {
+    function inter_p(p1, p2, leng, d) = 
+        let(
+            vp = p2 - p1,
+            u = vp / leng
+        )
+        p1 + u * d;
+
+    module _square_pursuit_3d(pts, diff_scale, diameter, n) {
+        if(n != 0) {
+            vp = pts[1] - pts[0];
+            leng = norm(vp);
+            d = leng * diff_scale;
+            
+            npts = [for(i = [0:3]) inter_p(pts[i], pts[(i + 1) % 4], leng, d)];
+            
+            hull_polyline3d(concat(npts, [npts[3], npts[0]]), diameter);
+            
+            _square_pursuit_3d(npts, diff_scale, diameter, n - 1);
+        }
+    }
+
+    half_length = length / 2;
+    pts = [
+        [0, 0, 0],
+        [length, 0, 0],
+        [half_length, half_length, sqrt(2) * half_length],
+        [0, length, 0]
+    ];    
+    
+    hull_polyline3d(concat(pts, [pts[3], pts[0]]), diameter);
+    
+    _square_pursuit_3d(pts, diff_scale, diameter, n - 1);
+}
+
+square_pursuit_3d(length, diff_scale, diameter, n);