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docs/lib3x-sf_solidifyT.md

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+# sf_solidifyT
+
+It solidifies two surfaces with triangular mesh. 
+
+**Since:** 3.1
+
+## Parameters
+
+- `points1` : A list of `[x, y, z]`s.
+- `points2` : A list of `[x, y, z]`s.
+- `triangles` : Determine which points are connected by an edge. All triangles have points in the same direction, counter-clockwise. See examples below.
+
+## Examples
+
+    use <triangle/tri_delaunay.scad>;
+    use <surface/sf_solidifyT.scad>;
+
+    points = [for(i = [0:50]) rands(-300, 300, 2)]; 
+    triangles = tri_delaunay(points);
+
+    pts = [for(p = points) [p[0], p[1], rands(100, 150, 1)[0]]];
+    pts2 = [for(p = pts) [p[0], p[1], p[2] - 100]];
+
+    sf_solidifyT(pts, pts2, triangles = triangles);	
+
+![sf_solidifyT](images/lib3x-sf_solidifyT-1.JPG)
+
+    use <triangle/tri_delaunay.scad>;
+    use <surface/sf_solidifyT.scad>;
+
+    thickness = .2;
+    a_step = 10;
+    r_step = 0.2;
+    scale = 100;
+
+    function f(x, y) = (pow(y,2)/pow(2, 2))-(pow(x,2)/pow(2, 2));
+
+    pts2d = [
+        for(a = [a_step:a_step:360])
+            for(r = [r_step:r_step:2])
+            let(
+                x = round(r * cos(a) * 100) / 100, 
+                y = round(r * sin(a) * 100) / 100
+            )
+            [x, y] 
+    ];
+
+    points1 = [for(p = pts2d) scale * [p[0], p[1], f(p[0], p[1])]];
+    points2 = [for(p = points1) [p[0], p[1], p[2] - scale * thickness]];
+    triangles = tri_delaunay(pts2d);
+
+
+    sf_solidifyT(points1, points2, triangles);
+
+![sf_solidifyT](images/lib3x-sf_solidifyT-2.JPG)

docs/lib3x-sf_thickenT.md

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+# sf_thickenT
+
+It thickens a surface with triangular mesh. 
+
+## Parameters
+
+- `points` : A list of `[x, y, z]`s.
+- `thickness` : The depth of the thickening.
+- `triangles` : Determine which points are connected by an edge. All triangles have points in the same direction, counter-clockwise. If it's ignored, `sf_thickenT` would use `[x, y]` to do Delaunay trianglation.  
+- `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_thickenT.scad>;
+
+	radius = 100;
+	width = 2;
+	thickness = .2;
+
+	a_step = 10;
+	r_step = 0.2;
+
+	function f(x, y) = (pow(y,2)/pow(2, 2))-(pow(x,2)/pow(2, 2));
+
+	points = [
+		for(a = [a_step:a_step:360])
+			for(r = [r_step:r_step:2])
+			let(
+				x = round(r * cos(a) * 100) / 100, 
+				y = round(r * sin(a) * 100) / 100
+			)
+			[x, y, f(x, y)] 
+	];
+
+	sf_thickenT(points, thickness);
+
+![sf_thickenT](images/lib3x-sf_thickenT-1.JPG)
+
+	use <triangle/tri_delaunay.scad>;
+	use <surface/sf_thickenT.scad>;
+
+	u_step = 10;
+	r_step = 0.2;
+	thickness = .2;
+
+	points = [
+		for(u = [0:u_step:360])
+			for(v = [-1:r_step:1])
+			let(
+				x = (1 + v / 2 * cos(u / 2)) * cos(u),
+				y = (1 + v / 2 * cos(u / 2)) * sin(u),
+				z = v / 2 * sin(u / 2)
+			)
+			[x, y, z]
+	];
+
+	triangles = tri_delaunay([
+		for(u = [0:u_step:360])
+			for(v = [-1:r_step:1])
+			[v, u]
+	]);
+
+	sf_thickenT(points, thickness, triangles);
+
+![sf_thickenT](images/lib3x-sf_thickenT-2.JPG)