update docs

docs/lib3x-bezier_surface.md

@@ -1,34 +0,0 @@
-# bezier_surface
-
-Given a set of control points, the `bezier_surface` function returns points of the Bézier surface. Combined with the `function_grapher` module defined in my library, you can create a Bézier surface.
-
-## Parameters
-
-- `t_step` : The distance between two points of the Bézier path.
-- `points` : A set of control points. See examples below.
-
-## Examples
-
-If you have 16 control points and combine with the `function_grapher` module:
-
-	use <bezier_surface.scad>; 
-	use <function_grapher.scad>;
-
-	t_step = 0.05;
-	thickness = 0.5;
-
-	ctrl_pts = [
-		[[0, 0, 20],  [60, 0, -35],   [90, 0, 60],    [200, 0, 5]],
-		[[0, 50, 30], [100, 60, -25], [120, 50, 120], [200, 50, 5]],
-		[[0, 100, 0], [60, 120, 35],  [90, 100, 60],  [200, 100, 45]],
-		[[0, 150, 0], [60, 150, -35], [90, 180, 60],  [200, 150, 45]]
-	];
-
-	g = bezier_surface(t_step, ctrl_pts);
-	function_grapher(g, thickness);    
-
-![bezier_surface](images/lib3x-bezier_surface-1.JPG)
-
-The following figure shows controll points and bazier curves around the surface.
-
-![bezier_surface](images/lib3x-bezier_surface-2.JPG)

docs/lib3x-contours.md

@@ -12,7 +12,7 @@ Computes contour polygons by applying [marching squares](https://en.wikipedia.or
 ## Examples
 
     use <hull_polyline2d.scad>;
-    use <function_grapher.scad>;
+	use <surface/sf_thicken.scad>;
     use <contours.scad>;
 
     min_value =  1;
@@ -29,7 +29,7 @@ Computes contour polygons by applying [marching squares](https://en.wikipedia.or
             ]
     ];
 
-    function_grapher(points, 1);
+    sf_thicken(points, 1);
 
     translate([max_value, 0, 0]) 
     for(z = [-30:5:30]) {

docs/lib3x-function_grapher.md

@@ -1,78 +0,0 @@
-# function_grapher
-
-Given a list of points `[x, y, f(x, y)]` where `f(x, y)` is a mathematics function, the `function_grapher` module can create the graph of `f(x, y)`.
-
-## Parameters
-
-- `points` : A list of points `[x, y, f(x, y)]`. See examples below.
-- `thickness` : The face or line thickness. Default to 1.
-- `style` : The style of the graph. It accepts `"FACES"`, `"LINES"`, `"HULL_FACES"` and `"HULL_LINES"`. The default value is `"FACES"` which simply takes `f(x, y) - thickness` for each point to build a bottom. It may cause thickness problems when slopes is high. The `"HULL_FACES"` value can solve the problem but is slow. When assigning `"LINES"`, it uses lines to connect points. The `"HULL_LINES"` is very very slow; however, the model might look smoother if you have a small `$fn`.
-- `$fa`, `$fs`, `$fn` : Used by the `circle` or `sphere` module internally. It affects the speed of rending. For example, a large `$fn` may be very slow when rending. Check [the circle module](https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Using_the_2D_Subsystem#circle) or [the sphere module](https://en.wikibooks.org/wiki/OpenSCAD_User_Manual/Primitive_Solids#sphere) for more details. 
-
-## Examples
-
-	use <function_grapher.scad>;
-	
-	points = [
-	    [[0, 0, 1], [1, 0, 2], [2, 0, 2], [3, 0, 3]],
-	    [[0, 1, 1], [1, 1, 4], [2, 1, 0], [3, 1, 3]],
-	    [[0, 2, 1], [1, 2, 3], [2, 2, 1], [3, 2, 3]],
-	    [[0, 3, 1], [1, 3, 3], [2, 3, 1], [3, 3, 3]]
-	];
-	
-	thickness = 0.5;
-	
-	function_grapher(points, thickness);
-
-![function_grapher](images/lib3x-function_grapher-1.JPG)
-
-	use <function_grapher.scad>;
-	
-	function f(x, y) = 
-	   30 * (
-	       cos(sqrt(pow(x, 2) + pow(y, 2))) + 
-	       cos(3 * sqrt(pow(x, 2) + pow(y, 2)))
-	   );
-	
-	thickness = 2;
-	min_value =  -200;
-	max_value = 200;
-	resolution = 10;
-	
-	points = [
-	    for(y = [min_value:resolution:max_value])
-	        [
-	            for(x = [min_value:resolution:max_value]) 
-	                [x, y, f(x, y)]
-	        ]
-	];
-	
-	function_grapher(points, thickness);
-
-![function_grapher](images/lib3x-function_grapher-2.JPG)
-
-	use <function_grapher.scad>;
-
-	function f(x, y) = 
-	   30 * (
-	       cos(sqrt(pow(x, 2) + pow(y, 2))) + 
-	       cos(3 * sqrt(pow(x, 2) + pow(y, 2)))
-	   );
-	
-	thickness = 2;
-	min_value =  -200;
-	max_value = 200;
-	resolution = 10;
-	style = "LINES"; 
-	
-	points = [
-	    for(y = [min_value:resolution:max_value])
-	        [
-	            for(x = [min_value:resolution:max_value]) 
-	                [x, y, f(x, y)]
-	        ]
-	];
-	
-	function_grapher(points, thickness, style);
-
-![function_grapher](images/lib3x-function_grapher-3.JPG)

docs/lib3x-nz_perlin2.md

@@ -14,7 +14,7 @@ Returns the 2D [Perlin noise](https://en.wikipedia.org/wiki/Perlin_noise) value
 
     use <util/rand.scad>;
     use <hull_polyline2d.scad>;
-    use <function_grapher.scad>;
+    use <surface/sf_thicken.scad>;
     use <noise/nz_perlin2.scad>;
     use <contours.scad>;
 
@@ -27,11 +27,11 @@ Returns the 2D [Perlin noise](https://en.wikipedia.org/wiki/Perlin_noise) value
         ]
     ];
 
-    function_grapher(points, 1);
+    sf_thicken(points, .1);
 
     translate([11, 0])
     for(isoline = contours(points, 0)) {
         hull_polyline2d(isoline, width = .1);
-    }  
+    }   
 
 ![nz_perlin2](images/lib3x-nz_perlin2-1.JPG)

docs/lib3x-nz_perlin2s.md

@@ -12,10 +12,7 @@ Returns 2D [Perlin noise](https://en.wikipedia.org/wiki/Perlin_noise) values at
 ## Examples
 
     use <util/rand.scad>;
-    use <hull_polyline2d.scad>;
-    use <function_grapher.scad>;
     use <noise/nz_perlin2s.scad>;
-    use <contours.scad>;
 
     seed = rand(0, 255);