# sf_thicken

It thickens a surface, described by a m * n list of `[x, y, z]`s.

## Parameters

- `points` : A m * n list of `[x, y, z]`s. See examples below.
- `thickness` : The depth of the thickening.
- `direction` : The direction of thickening. It accepts `"BOTH"` (default), `"FORWARD"` or `"BACKWARD"`. Thickening is applied in both directions from the surface, the direction of the surface normals or the opposite direction to the surface normals. It also accept a direction vector `[x, y, z]`. Thickening is only applied in the direction you give.

## Examples

	use <surface/sf_thicken.scad>;

	points = [
		[[0, 0, 1], [1, 0, 2.5], [2, 0, 2], [3, 0, 2.5]],
		[[0, 1, 1], [1, 1, 2], [2, 1, 1], [3, 1, 2]],
		[[0, 2, 1], [1, 2, 2.3], [2, 2, 2], [3, 2, 2.2]],
		[[0, 3, 1], [1, 3, 2], [2, 3, 1], [3, 3, 2]]
	];

	thickness = 0.25;

	sf_thicken(points, thickness);

![sf_thicken](images/lib3x-sf_thicken-1.JPG)

	use <surface/sf_thicken.scad>;

	function f(x, y) = 
        let(leng = norm([x, y]))
		30 * (cos(leng) + cos(3 * leng));

	thickness = 3;
	min_value =  -200;
	max_value = 200;
	resolution = 10;

	surface1 = [
		for(y = [min_value:resolution:max_value])
		[
			for(x = [min_value:resolution:max_value]) 
				[x, y, f(x, y) + 100]
		]
	];
	sf_thicken(surface1, thickness);

![sf_thicken](images/lib3x-sf_thicken-2.JPG)

	use <surface/sf_thicken.scad>;

	function f(x, y) = x + y;

	thickness = 20;
	min_value = -50;
	max_value = 50;
	resolution = 5;

	surface1 = [
		for(y = [min_value:resolution:max_value])
		[
			for(x = [min_value:resolution:max_value]) 
				[x, y, f(x, y) + 100]
		]
	];
	sf_thicken(surface1, thickness, direction = [1, 1, -1]);

![sf_thicken](images/lib3x-sf_thicken-3.JPG)