updated docs

README.md

@@ -52,9 +52,12 @@ Some modules may depend on other modules. For example, the `polyline2d` module d
     - [archimedean_spiral](https://openhome.cc/eGossip/OpenSCAD/lib-archimedean_spiral.html)
     - [sphere_spiral](https://openhome.cc/eGossip/OpenSCAD/lib-sphere_spiral.html)
 
-- Other
+- Extrude
     - [box_extrude](https://openhome.cc/eGossip/OpenSCAD/lib-box_extrude.html)
+	- [ellipse_extrude](https://openhome.cc/eGossip/OpenSCAD/lib-ellipse_extrude.html)
     - [stereographic_extrude](https://openhome.cc/eGossip/OpenSCAD/lib-stereographic_extrude.html)
+
+- Other
     - [turtle2d](https://openhome.cc/eGossip/OpenSCAD/lib-turtle2d.html)
     - [turtle3d](https://openhome.cc/eGossip/OpenSCAD/lib-turtle3d.html)
 	- [log](https://openhome.cc/eGossip/OpenSCAD/lib-log.html)

docs/lib-ellipse_extrude.md

@@ -0,0 +1,49 @@
+# ellipse_extrude
+
+Extrudes a 2D object along the path of an ellipse from 0 to 180 degrees. The semi-major axis is not necessary because it's eliminated while calculating.
+
+## Parameters
+
+- `semi_minor_axis` : The semi-minor axis of the ellipse.
+- `height` : The extruded height. It defaults to `semi_minor_axis` if ignored. The `height` should not greater than `semi_minor_axis`. If it's greater than `semi_minor_axis`, the module will use `semi_minor_axis`.
+- `center`, `convexity`, `twist`, `slices`: The same as respective parameters of `linear_extrude`.
+
+## Examples
+
+	include <ellipse_extrude.scad>;
+	
+	semi_minor_axis = 5;
+	 
+	ellipse_extrude(semi_minor_axis) 
+	    circle(semi_minor_axis * 2);
+
+![ellipse_extrude](images/lib-ellipse_extrude-1.JPG)
+
+	include <ellipse_extrude.scad>;
+	
+	semi_minor_axis = 5;
+	 
+	ellipse_extrude(semi_minor_axis, height = 4.5) 
+	    text("A", valign = "center", halign = "center");
+
+![ellipse_extrude](images/lib-ellipse_extrude-2.JPG)
+
+    include <ellipse_extrude.scad>;
+
+	semi_minor_axis = 5;
+	 
+	ellipse_extrude(semi_minor_axis) 
+	    text("♥", size = 40, valign = "center", halign = "center");
+	mirror([0, 0, 1]) ellipse_extrude(semi_minor_axis) 
+	    text("♥", size = 40, valign = "center", halign = "center");
+
+![ellipse_extrude](images/lib-ellipse_extrude-3.JPG)
+
+	include <ellipse_extrude.scad>;
+	
+	semi_minor_axis = 10;
+	 
+	ellipse_extrude(semi_minor_axis, twist = 30, slices = 10) 
+	    text("♥", size = 40, valign = "center", halign = "center");
+
+![ellipse_extrude](images/lib-ellipse_extrude-4.JPG)