added rounded_cube

README.md

@@ -33,6 +33,7 @@ Some modules may depend on other modules. For example, the `polyline2d` module d
 	- [hexagons](https://openhome.cc/eGossip/OpenSCAD/lib-hexagons.html)
 
 - 3D
+	- [rounded_cube](https://openhome.cc/eGossip/OpenSCAD/lib-rounded_cube.html)
 	- [line3d](https://openhome.cc/eGossip/OpenSCAD/lib-line3d.html)
 	- [polyline3d](https://openhome.cc/eGossip/OpenSCAD/lib-polyline3d.html)
 	- [hull_polyline3d](https://openhome.cc/eGossip/OpenSCAD/lib-hull_polyline3d.html)

docs/lib-rounded_cube.md

@@ -0,0 +1,44 @@
+# rounded_cube
+
+Creates a cube in the first octant. When center is true, the cube is centered on the origin.
+
+## Parameters
+
+- `size` : Accepts a single value, cube with all sides this length. It also accepts 3 value array `[x, y, z]`, cube with dimensions `x`, `y` and `z`.
+- `corner_r` : The corner is one-eight of a sphere. The `corner_r` parameter determines the sphere radius.
+- `center` : `false` (default), 1st (positive) octant, one corner at (0,0,0). `true`, cube is centered at (0,0).
+- `$fa`, `$fs`, `$fn` : Used to control the four quadrants. Check [the circle module](https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Using_the_2D_Subsystem#circle) for more details. The final fragments of a sphere will be a multiple of 4 to fit edges.
+
+## Examples
+
+	include <rounded_cube.scad>;
+	
+	rounded_cube(20, 5);
+
+![rounded_cube](images/lib-rounded_cube-1.JPG)
+
+	include <rounded_cube.scad>;
+	
+	rounded_cube(
+	    size = [50, 25, 15], 
+	    corner_r = 5,
+	    center = true
+	);
+
+![rounded_cube](images/lib-rounded_cube-2.JPG)
+
+	include <rounded_cube.scad>;
+	
+	$fn = 8;
+	
+	rounded_cube(
+	    size = [50, 25, 15], 
+	    corner_r = 5,
+	    center = true
+	);
+
+![rounded_cube](images/lib-rounded_cube-3.JPG)
+
+
+
+

src/rounded_cube.scad

@@ -0,0 +1,57 @@
+/**
+* rounded_cube.scad
+*
+* Creates a rounded cube in the first octant. 
+* When center is true, the cube is centered on the origin.
+* 
+* @copyright Justin Lin, 2017
+* @license https://opensource.org/licenses/lgpl-3.0.html
+*
+* @see https://openhome.cc/eGossip/OpenSCAD/lib-rounded_cube.html
+*
+**/
+
+module rounded_cube(size, corner_r, center = false) {
+    x = len(size) == undef ? size : size[0];
+    y = len(size) == undef ? size : size[1];
+    z = len(size) == undef ? size : size[2];
+
+    frags = $fn > 0 ? 
+        ($fn >= 3 ? $fn : 3) : 
+        max(min(360 / $fa, corner_r * 6.28318 / $fs), 5);
+
+    remain = frags % 4;
+    corner_frags = (remain / 4) > 0.5 ? frags - remain + 4 : frags - remain;
+    edge_d = corner_r * cos(180 / corner_frags);
+
+    half_x = x / 2;
+    half_y = y / 2;
+    half_z = z / 2;
+    
+    half_l = half_x - edge_d;
+    half_w = half_y - edge_d;
+    half_h = half_z - edge_d;
+    
+    half_cube_leng = size / 2;
+    half_leng = half_cube_leng - edge_d;
+    
+    translate(center ? [0, 0, 0] : [half_x, half_y, half_z]) hull() {
+            translate([-half_l, -half_w, half_h]) 
+                sphere(corner_r, $fn = corner_frags);
+            translate([half_l, -half_w, half_h]) 
+                sphere(corner_r, $fn = corner_frags);
+            translate([half_l, half_w, half_h]) 
+                sphere(corner_r, $fn = corner_frags);
+            translate([-half_l, half_w, half_h]) 
+                sphere(corner_r, $fn = corner_frags);
+
+            translate([-half_l, -half_w, -half_h]) 
+                sphere(corner_r, $fn = corner_frags);
+            translate([half_l, -half_w, -half_h]) 
+                sphere(corner_r, $fn = corner_frags);
+            translate([half_l, half_w, -half_h]) 
+                sphere(corner_r, $fn = corner_frags);
+            translate([-half_l, half_w, -half_h]) 
+                sphere(corner_r, $fn = corner_frags);        
+    }
+}