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improved thread_helix docs

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fixed bugs in spiral_sweep: wrong sampling rate, left_handed broken
This commit is contained in:
Adrian Mariano
2021-08-28 08:57:09 -04:00
parent 352436938f
commit 6ef2f71255
2 changed files with 30 additions and 16 deletions
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@@ -1055,7 +1055,7 @@ module extrude_from_to(pt1, pt2, convexity, twist, scale, slices) {
// spiral_sweep(poly, h=200, r=50, twist=1080, $fn=36);
module spiral_sweep(poly, h, r, twist=360, higbee, center, r1, r2, d, d1, d2, higbee1, higbee2, internal=false, anchor, spin=0, orient=UP) {
higsample = 10; // Oversample factor for higbee tapering
dummy1=assert(twist>0);
// dummy1=assert(twist>0);
bounds = pointlist_bounds(poly);
yctr = (bounds[0].y+bounds[1].y)/2;
xmin = bounds[0].x;
@@ -1065,7 +1065,8 @@ module spiral_sweep(poly, h, r, twist=360, higbee, center, r1, r2, d, d1, d2, hi
r1 = get_radius(r1=r1, r=r, d1=d1, d=d, dflt=50);
r2 = get_radius(r1=r2, r=r, d1=d2, d=d, dflt=50);
sides = segs(max(r1,r2));
ang_step = 360/sides;
dir = sign(twist);
ang_step = 360/sides*dir;
anglist = [for(ang = [0:ang_step:twist-EPSILON]) ang,
twist];
higbee1 = first_defined([higbee1, higbee, 0]);
@@ -1073,23 +1074,24 @@ module spiral_sweep(poly, h, r, twist=360, higbee, center, r1, r2, d, d1, d2, hi
higang1 = 360 * higbee1 / (2 * r1 * PI);
higang2 = 360 * higbee2 / (2 * r2 * PI);
dummy2=assert(higbee1>=0 && higbee2>=0)
assert(higang1 < twist/2)
assert(higang2 < twist/2);
assert(higang1 < dir*twist/2)
assert(higang2 < dir*twist/2);
function polygon_r(N,theta) =
let( alpha = 360/N )
cos(alpha/2)/(cos(posmod(theta,alpha)-alpha/2));
function higsize(a) = lookup(a,[
[-0.001, higang1>0?0:1],
if (higang1>0) for (x=[0.125:0.125:1]) [ x*higang1, pow(x,1/2)],
if (higang2>0) for (x=[0.125:0.125:1]) [twist-x*higang2, pow(x,1/2)],
[twist+0.001, higang2>0?0:1]
[-0.001*dir, higang1>0?0:1],
if (higang1>0) for (x=[0.125:0.125:1]) [ dir*x*higang1, pow(x,1/2)],
if (higang2>0) for (x=[0.125:0.125:1]) [twist-dir*x*higang2, pow(x,1/2)],
[twist+dir*0.001, higang2>0?0:1]
]);
interp_ang = [
for(i=idx(anglist,e=-2))
each lerpn(anglist[i],anglist[i+1],
(higang1<anglist[i+1] || (twist-higang2>anglist[i])) ? ceil((anglist[i+1]-anglist[i])/ang_step*higsample)
: 1,
(higang1>0 && higang1>dir*anglist[i+1]
|| (higang2>0 && higang2>dir*(twist-anglist[i]))) ? ceil((anglist[i+1]-anglist[i])/ang_step*higsample)
: 1,
endpoint=false),
last(anglist)
];
@@ -1110,12 +1112,12 @@ module spiral_sweep(poly, h, r, twist=360, higbee, center, r1, r2, d, d1, d2, hi
];
vnf = vnf_vertex_array(
points, col_wrap=true, caps=true, reverse=true,
points, col_wrap=true, caps=true, reverse=dir>0?true:false,
style=higbee1>0 || higbee2>0 ? "quincunx" : "alt"
);
attachable(anchor,spin,orient, r1=r1, r2=r2, l=h) {
vnf_polyhedron(vnf, convexity=ceil(2*twist/360));
vnf_polyhedron(vnf, convexity=ceil(2*dir*twist/360));
children();
}
}