84 lines
2.4 KiB
OpenSCAD
84 lines
2.4 KiB
OpenSCAD
//
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// NopSCADlib Copyright Chris Palmer 2018
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// nop.head@gmail.com
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// hydraraptor.blogspot.com
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//
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// This file is part of NopSCADlib.
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//
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// NopSCADlib is free software: you can redistribute it and/or modify it under the terms of the
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// GNU General Public License as published by the Free Software Foundation, either version 3 of
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// the License, or (at your option) any later version.
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//
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// NopSCADlib is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
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// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
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// See the GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License along with NopSCADlib.
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// If not, see <https://www.gnu.org/licenses/>.
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//
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include <../core.scad>
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use <../utils/bezier.scad>
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use <../utils/sweep.scad>
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use <../utils/annotation.scad>
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function find_min_z(path, i = 1, best_i = 0) =
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i >= len(path) ? best_i
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: find_min_z(path, i + 1, path[i].z < path[best_i].z ? i : best_i);
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module beziers() {
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//
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// Make Bezier control points to give specified length
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//
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control_points = adjust_bezier_length([[0, 0, 100], [0, 0, 0], [200, 0, 20], [100, -100, 50]], 250);
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//
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// Draw control points
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//
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color("green")
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for(p = control_points)
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translate(p)
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sphere(1);
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//
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// Lines joining the control points
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//
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color("red")
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sweep(control_points, circle_points(0.5, $fn = 64));
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//
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// Bezier curve path from control points
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//
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curve = bezier_path(control_points);
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//
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// Draw the curve
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//
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sweep(curve, circle_points(2, $fn = 64));
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//
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// Length computed from control points
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//
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length = bezier_length(control_points);
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//
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// Length computed from curve
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//
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length2 = path_length(curve);
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assert(str(length) == str(length2), str(length, " ", length2));
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//
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// Minimum Z
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//
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min_z = bezier_min_z(control_points);
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i = find_min_z(curve);
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assert(str(min_z) == str(curve[i].z));
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color("blue") {
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translate(curve[i] + [0, 0, 2])
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arrow();
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translate(curve[i] - [0, 0, 2])
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vflip()
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arrow();
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}
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translate(control_points[1] - [0, 0, 2])
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label(str("bezier_length = ", length, ", bezier_min_z = ", bezier_min_z(curve)), valign = "top");
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}
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if($preview)
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beziers();
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