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Smoother higbee for spiral_sweep (don't linear interpolate square root)

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Adrian Mariano 2021-08-28 10:14:29 -04:00
parent 6ef2f71255
commit 110dc09cb7
1 changed files with 13 additions and 16 deletions
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@ -1074,18 +1074,14 @@ 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 < dir*twist/2)
assert(higang2 < dir*twist/2);
assert(higang1 < dir*twist/2,"Higbee1 is more than half the threads")
assert(higang2 < dir*twist/2,"Higbee2 is more than half the threads");
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*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]
]);
higofs = pow(0.05,2); // Smallest hig scale is the square root of this value
function taperfunc(x) = sqrt((1-higofs)*x+higofs);
interp_ang = [
for(i=idx(anglist,e=-2))
each lerpn(anglist[i],anglist[i+1],
@ -1098,15 +1094,16 @@ module spiral_sweep(poly, h, r, twist=360, higbee, center, r1, r2, d, d1, d2, hi
skewmat = affine3d_skew_xz(xa=atan2(r2-r1,h));
points = [
for (a = interp_ang) let (
hsc = higsize(a),
hsc = dir*a<higang1 ? taperfunc(dir*a/higang1)
: dir*(twist-a)<higang2 ? taperfunc(dir*(twist-a)/higang2)
: 1,
u = a/twist,
r = lerp(r1,r2,u),
mat = affine3d_zrot(a) *
affine3d_translate([polygon_r(sides,a)*r, 0, h * (u-0.5)]) *
affine3d_xrot(90) *
skewmat *
//affine3d_scale([hsc,lerp(hsc,1,0.25),1]),
scale([hsc,lerp(hsc,1,0.25),1], cp=[internal ? xmax : xmin, yctr, 0]),
mat = affine3d_zrot(a)
* affine3d_translate([polygon_r(sides,a)*r, 0, h * (u-0.5)])
* affine3d_xrot(90)
* skewmat
* scale([hsc,lerp(hsc,1,0.25),1], cp=[internal ? xmax : xmin, yctr, 0]),
pts = apply(mat, poly)
) pts
];