Add round gates library

round_gates.scad

@@ -0,0 +1,40 @@
+gate_height = 50;
+
+// ROUND GATES: CIR, OCTR, OCTNR
+module pivot (throw, shaft_r) {
+  top_r = gate_height * tan(throw) + shaft_r;
+  cylinder(h = gate_height, r1 = shaft_r, r2 = top_r);
+}
+ 
+module pivot_square (throw, shaft_r, throw_extend = 0) {  
+  hull() {
+    rotate([0,throw,0])
+      pivot(gate_height, throw_extend, shaft_r);
+    rotate([0,-throw,0])
+      pivot(gate_height, throw_extend, shaft_r);
+    rotate([0,0,90]) {
+      rotate([0,throw,0])
+        pivot(gate_height, throw_extend, shaft_r);
+      rotate([0,-throw,0])
+        pivot(gate_height, throw_extend, shaft_r);
+    }
+  };
+}
+
+module cir_gate (throw, shaft_r) { 
+  pivot(throw, shaft_r); 
+}
+module octr_gate (throw, shaft_r) {
+  union(){
+    rotate([0,0,45])
+      pivot_square(throw, shaft_r);
+    pivot_square(throw, shaft_r);
+  }
+};
+module octnr_gate (throw, shaft_r) {
+  union(){
+    rotate([0,0,45])
+      pivot_square(throw + 1, shaft_r, 1);
+    pivot_square(throw, shaft_r);
+  }
+};