Simon Brooke
113546782f
fragility in the way OpenSCAD handles name collisions. This makes mixing libraries highly problematic. Needs thought.
74 lines
2 KiB
OpenSCAD
74 lines
2 KiB
OpenSCAD
// fourbar.scad
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// (c) Simon Brooke 2025; CC-BY-SA
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include <BentSim/Library/Bike_accessories.scad>
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include <NACAAirfoils/files/Naca4.scad>
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include <library/skew.scad>
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module fourbar_leg(length=1000, chord=100, long_skew=30, lat_skew=30) {
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h = length * cos(lat_skew) * cos( long_skew);
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w = length * sin( lat_skew);
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d = length * sin( long_skew);
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translate([0, 0-w, 0]) {
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// upper pivot needs a complex trig transformation!
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translate([d - (chord/2), w, h + chord])
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rotate([0, 90+long_skew, 0])
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color("black")
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cylinder(h=chord, r=12);
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// lower pivot:
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translate([0 - chord, 0, (chord/2 * sin(long_skew))])
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rotate([0, 90+long_skew, 0])
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color("black")
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cylinder(h=chord, r=12);
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// aerofoil section
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sskew([0, long_skew, 0, 0, 0, 0])
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rotate([lat_skew, 0, 180])
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color("black")
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airfoil(h=length, L=chord);
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}
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}
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module fourbar_axle_half( length, chord) {
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translate([0, 0, -120])
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rotate([82, 0, 180])
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color("black")
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airfoil(h=length, L=chord);
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// lower knuckle
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translate([-chord, length, -60])
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color("black")
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cube([chord, chord/4, chord/2]);
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// wheel
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translate([0, length + 50, -50])
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// Pierre Rouzeau's wheel is beautifully modelled and parameterised, but it doesn't seem to be scaled as I'd expect...
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wheel(rim=451, spoke_nbr=32);
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}
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module fourbar(length=1000, chord=100, long_skew=30, lat_skew=30, shoulder=650) {
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w = (length * sin( lat_skew)) + ( shoulder / 2);
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translate([0, 0-(shoulder/2), 0])
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fourbar_leg( length, chord, long_skew, lat_skew);
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translate([0, (shoulder/2), 0])
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mirror([0, 1, 0])
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fourbar_leg(length, chord, long_skew, lat_skew);
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fourbar_axle_half(w, chord);
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mirror([0, 1, 0])
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fourbar_axle_half(w, chord);
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}
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// fourbar(); |