added box_extrude

README.md

@@ -26,4 +26,7 @@ I've been using OpenSCAD for years and created some funny things. Some of them i
 - Path
     - [circle_path](https://openhome.cc/eGossip/OpenSCAD/lib-circle_path.html)
     - [bezier](https://openhome.cc/eGossip/OpenSCAD/lib-bezier.html)
-    - [cylinder_spiral](https://openhome.cc/eGossip/OpenSCAD/lib-cylinder_spiral.html)
+    - [cylinder_spiral](https://openhome.cc/eGossip/OpenSCAD/lib-cylinder_spiral.html)
+
+- Other
+    - [box_extrude](https://openhome.cc/eGossip/OpenSCAD/lib-box_extrude.html)

docs/lib-box_extrude.md

@@ -0,0 +1,21 @@
+# box_extrude
+
+Create a box (container) from a 2D object.
+
+## Parameters
+
+- `height` : The box height.
+- `shell_thickness` : The thickness between the exterior and interior..
+
+## Examples
+
+	box_extrude(height = 30, shell_thickness = 2) 
+	    circle(r = 30);
+
+![box_extrude](images/lib-box_extrude-1.JPG)
+
+box_extrude(height = 30, shell_thickness = 2) 
+    text("XD", size = 40, font = "Cooper Black");
+
+![box_extrude](images/lib-box_extrude-2.JPG)
+

src/box_extrude.scad

@@ -0,0 +1,27 @@
+/**
+* box_extrude.scad
+*
+* Create a box (container) from a 2D object.
+* 
+* @copyright Justin Lin, 2017
+* @license https://opensource.org/licenses/lgpl-3.0.html
+*
+* @see https://openhome.cc/eGossip/OpenSCAD/lib-box_extrude.html
+*
+**/
+
+module box_extrude(height, shell_thickness) {
+    linear_extrude(shell_thickness)
+        children();
+        
+    linear_extrude(height) 
+        difference() {
+            children();
+            offset(delta = -shell_thickness) 
+                children();
+        }    
+}
+
+box_extrude(height = 30, shell_thickness = 2) 
+    text("XD", size = 40, font = "Cooper Black");
+