add doc

README.md

@@ -200,7 +200,7 @@ See [examples](examples).
 - [noise/nz_worley2s](https://openhome.cc/eGossip/OpenSCAD/lib2x-nz_worley2s.html)
 - [noise/nz_worley3](https://openhome.cc/eGossip/OpenSCAD/lib2x-nz_worley3.html)
 - [noise/nz_worley3s](https://openhome.cc/eGossip/OpenSCAD/lib2x-nz_worley3s.html)
-- noise/nz_cell
+- [noise/nz_cell](https://openhome.cc/eGossip/OpenSCAD/lib2x-nz_cell.html)
 
 ## Bugs and Feedback
 

docs/lib2x-nz_cell.md

@@ -0,0 +1,48 @@
+# nz_cell
+
+It's an implementation of [Worley noise](https://en.wikipedia.org/wiki/Worley_noise). The feature points can be customized. The function returns `[cell_x, cell_y(, cell_z), noise]` value at the (x, y(,z)) coordinate. 
+
+**Since:** 2.3
+
+## Parameters
+points, p, dist
+- `points` : The feature points, can be 2D or 3D. 
+- `p` : The pixel or voxel coordinate.
+- `dist` : The noise value of each point is based on its distance to other cells. Different distance strategies make different noises. The `dist` parameter accepts `"euclidean"`, `"manhattan"`, `"chebyshev"` or `"border"`.
+
+## Examples
+
+    use <noise/nz_cell.scad>;
+    use <golden_spiral.scad>;
+
+    size = [100, 50];
+    half_size = size / 2;
+
+    pts_angles = golden_spiral(
+        from = 3, 
+        to = 10, 
+        point_distance = 3
+    );
+
+    feature_points = [for(pt_angle = pts_angles) pt_angle[0] + half_size];
+    noised = [
+        for(y = [0:size[1] - 1]) 
+            for(x = [0:size[0] - 1]) 
+                [x, y, nz_cell(feature_points, [x, y])]
+    ];
+
+    max_dist = max([for(n = noised) n[2]]);
+
+    for(n = noised) {
+        c = abs(n[2] / max_dist);
+        color([c, c, c])
+        linear_extrude(n[2] + 0.1)
+        translate([n[0], n[1]])
+            square(1);
+    }
+
+![nz_cell](images/lib2x-nz_cell-1.JPG)
+
+You can build a model such as:
+
+![nz_cell](images/lib2x-nz_cell-2.JPG)

src/experimental/demo/nz_cell_demo.scad

@@ -1,28 +0,0 @@
-use <noise/nz_cell.scad>;
-use <golden_spiral.scad>;
-
-size = [100, 50];
-half_size = size / 2;
-
-pts_angles = golden_spiral(
-    from = 3, 
-    to = 10, 
-    point_distance = 3
-);
-
-feature_points = [for(pt_angle = pts_angles) pt_angle[0] + half_size];
-noised = [
-    for(y = [0:size[1] - 1]) 
-        for(x = [0:size[0] - 1]) 
-            [x, y, nz_cell(feature_points, [x, y])]
-];
-
-max_dist = max([for(n = noised) n[2]]);
-
-for(n = noised) {
-    c = abs(n[2] / max_dist);
-    color([c, c, c])
-    linear_extrude(n[2] + 0.1)
-    translate([n[0], n[1]])
-        square(1);
-}

src/noise/nz_cell.scad

@@ -1,3 +1,13 @@
+/**
+* nz_cell.scad
+*
+* @copyright Justin Lin, 2020
+* @license https://opensource.org/licenses/lgpl-3.0.html
+*
+* @see https://openhome.cc/eGossip/OpenSCAD/lib2x-nz_cell.html
+*
+**/
+
 use <noise/_impl/_nz_cell_impl.scad>;
     
 function nz_cell(points, p, dist = "euclidean") =