add wormhole

examples/wormhole.scad

@@ -0,0 +1,56 @@
+use <rounded_square.scad>;
+use <polyline_join.scad>;
+use <hollow_out.scad>;
+
+length = 100;
+width = 50;
+depth = 40;
+thickness = 3;
+hole_r = 8;
+
+$fn = 24;
+
+wormhole(length, width, depth, thickness, hole_r);
+
+module wormhole(length, width, depth, thickness, hole_r) {
+    a_step = 360 / $fn;
+    r1 = depth / 2;
+    r2 = width / 4;
+    half_thickness = thickness / 2;
+
+    plane = concat(
+        [[length - r1, r1]], 
+        [for(a = [90:a_step:270]) r1 * [cos(a), sin(a)]],
+        [[length - r1, -r1]]
+    );
+
+    difference() {
+        rotate([90, 0, 0])
+        linear_extrude(width, center = true)
+            polyline_join(plane)
+                    square(thickness, center = true);
+            
+        translate([(length - r1) / 2, 0])
+        linear_extrude(depth + thickness * 2, center = true)
+            circle(r2 + hole_r);
+    }
+
+
+    hole_profile = concat(
+        [for(a = [90:a_step:180]) r2 * [cos(a), sin(a)]], 
+        [[-r2, -(r1 - r2) + half_thickness]]
+    );
+    
+    module hole() {
+        translate([(length - r1) / 2, 0, r1 - r2])
+        rotate_extrude()
+        translate([r2 + half_thickness + hole_r, 0])
+            polyline_join(hole_profile)
+                square(thickness, center = true);
+    }
+
+    hole();
+
+    mirror([0, 0, 1])
+        hole() ;
+}