Add rounded N-gon

scad/util/common.scad

@@ -37,3 +37,19 @@ module roundRect(w, h, r) {
     square([w, h], center=true);
   }
 }
+
+
+/**
+  *
+  * TODO: Proper documentation!
+  *
+  * `d` the diameter; measured corner-to-corner for even corner numbers
+  * `n` number of corners
+  * `r` corner radius
+  */
+module roundNGon(d, n, r) {
+  minkowski() {
+    circle(d=d - 2*r, $fn=n);
+    if (r > 0) circle(r=r);
+  }
+}