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docs/lib-path_scaling_sections.md

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+# path_scaling_sections
+
+Given a edge path with the first point [x, 0, 0] or [0, y, 0] at the outline of a shape. This function use the path to calculate scaling factors and returns all scaled sections. Combined with the `polysections` module, you can create a extrusion with the path as an edge.
+
+**Since:** 1.2.
+
+## Parameters
+
+- `shape_pts` : A list of points represent a shape.
+- `edge_path` : A list of points represent the edge path.
+
+## Examples
+
+	include <hull_polyline3d.scad>;
+	include <shape_taiwan.scad>;
+	include <path_scaling_sections.scad>;
+	include <m_scaling.scad>;
+	include <polysections.scad>;
+
+	taiwan = shape_taiwan(100);
+	fst_pt = [13, 0, 0];
+
+	edge_path = [
+		fst_pt,
+		fst_pt + [0, 0, 10],
+		fst_pt + [10, 0, 20],
+		fst_pt + [8, 0, 30],
+		fst_pt + [12, 0, 40],
+		fst_pt + [0, 0, 50],
+		fst_pt + [0, 0, 60]
+	];
+
+	#hull_polyline3d(edge_path);
+	polysections(path_scaling_sections(taiwan, edge_path));
+
+![path_scaling_sections](images/lib-path_scaling_sections-1.JPG)
+
+	include <hull_polyline3d.scad>;
+	include <shape_taiwan.scad>;
+	include <path_scaling_sections.scad>;
+	include <m_scaling.scad>;
+	include <polysections.scad>;
+	include <bezier_curve.scad>;
+
+
+	taiwan = shape_taiwan(100);
+	fst_pt = [13, 0, 0];
+
+	edge_path = bezier_curve(0.05, [
+		fst_pt,
+		fst_pt + [0, 0, 10],
+		fst_pt + [10, 0, 20],
+		fst_pt + [8, 0, 30],
+		fst_pt + [12, 0, 40],
+		fst_pt + [0, 0, 50],
+		fst_pt + [0, 0, 60]
+	]);
+
+	#hull_polyline3d(edge_path);
+	polysections(path_scaling_sections(taiwan, edge_path));
+
+![path_scaling_sections](images/lib-path_scaling_sections-2.JPG)
+
+	include <shape_taiwan.scad>;
+	include <path_scaling_sections.scad>;
+	include <m_scaling.scad>;
+	include <polysections.scad>;
+	include <bezier_curve.scad>;
+	include <rotate_p.scad>;
+
+	taiwan = shape_taiwan(100);
+	fst_pt = [13, 0, 0];
+
+	edge_path = bezier_curve(0.05, [
+		fst_pt,
+		fst_pt + [0, 0, 10],
+		fst_pt + [10, 0, 20],
+		fst_pt + [8, 0, 30],
+		fst_pt + [12, 0, 40],
+		fst_pt + [0, 0, 50],
+		fst_pt + [0, 0, 60]
+	]);
+
+	leng = len(edge_path);
+	twist = 90;
+	twist_step = twist / leng;
+	sections = path_scaling_sections(taiwan, edge_path);
+
+	rotated_sections = [
+		for(i = [0:leng - 1]) 
+		[
+			for(p = sections[i]) 
+				rotate_p(p, twist_step * i)        
+		]
+	];
+
+	polysections(rotated_sections);
+
+![path_scaling_sections](images/lib-path_scaling_sections-3.JPG)