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Merge pull request #1507 from adrianVmariano/master

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Will hirth fixes never cease?
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Revar Desmera 2024-11-17 21:41:15 -08:00 committed by GitHub
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2 changed files with 34 additions and 4 deletions
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36
joiners.scad
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@ -1262,7 +1262,14 @@ module rabbit_clip(type, length, width, snap, thickness, depth, compression=0.1
// The joint is constructed with a tooth peak aligned with the X+ axis.
// For two hirth joints to mate they must have the same tooth count, opposite cone angles, and the chamfer/rounding values
// must be equal. (One can be chamfered and one rounded, but with the same value.) The rotation required to mate the parts
// depends on the skew and whether the tooth count is odd or even. To apply this rotation automatically, set `rot=true`.
// depends on the skew and whether the tooth count is odd or even. To apply this rotation automatically, set `rot=true`.
// .
// When you pick extreme parameters such as very large cone angle, or very small tooth count (e.g. 2 or 3), the joint may
// develop a weird shape, and the shape may be unexpectedly sensitive to things like whether chamfering is enabled. It is difficult
// to identify the point where the shapes become odd, or even perhaps invalid. For example, with 2 teeth a skew of 0.95 works fine, but
// a skew of 0.97 produces a truncated shape and 0.99 produces a 2-part shape. A skew of 1 produces a degenerate, invalid shape.
// Since it's hard to determine which parameters, exactly, produce "bad" outcomes, we have chosen not to limit the production
// of the extreme shapes, so take care if using extreme parameter values.
// Named Anchors:
// "teeth_bot" = center of the joint, aligned with the bottom of the (unchamfered/unrounded) teeth, pointing DOWN.
// Arguments:
@ -1351,7 +1358,7 @@ module hirth(n, ir, or, id, od, tooth_angle=60, cone_angle=0, chamfer, rounding,
];
full = deduplicate(concat(basicprof, reverse(xflip(basicprof))));
skewed = back(valley_angle, skew(sxy=skew*angle/(ridge_angle-valley_angle),fwd(valley_angle,full)));
profile = is_undef(rounding) ? skewed
pprofile = is_undef(rounding) ? skewed
:
let(
segs = max(16,segs(or*rounding)),
@ -1360,20 +1367,43 @@ module hirth(n, ir, or, id, od, tooth_angle=60, cone_angle=0, chamfer, rounding,
roundpts = round_corners(skewed, joint=joints, closed=false,$fn=segs)
)
roundpts;
profile = [
for(i=[0:1:len(pprofile)-2]) each [pprofile[i],
if (pprofile[i+1].x-pprofile[i].x > 90) // Interpolate an extra point if angle > 90 deg
let(
edge = cyl_proj(or, select(pprofile,i,i+1)),
cutpt = xyz_to_spherical(lerp(edge[0],edge[1],.48)) // Exactly .5 is too close to or crosses the origin
)
[cutpt.y,90-cutpt.z]
],
last(pprofile)
];
// This code computes the realized tooth angle
// out = cyl_proj(or, pprofile);
// in = cyl_proj(ir,pprofile);
// p1 = plane3pt(out[0], out[1], in[1]);
// p2 = plane3pt(out[2], out[1], in[1]);
// echo(toothang=vector_angle(plane_normal(p1), plane_normal(p2)));
bottom = min([tan(valley_angle)*ir,tan(valley_angle)*or])-base-cone_height*ir;
safebottom = min([tan(valley_angle)*ir/factor,tan(valley_angle)*or*factor])-base-(crop?1:0)-cone_height*ir;
ang_ofs = !rot ? -skew*angle
: n%2==0 ? -(angle-skew*angle) - skew*angle
: -angle*(2-skew)-skew*angle;
topinner = down(cone_height*ir,[for(ang=lerpn(0,360,n,endpoint=false))
each zrot(ang+ang_ofs,cyl_proj(ir/factor,profile))]);
topouter = down(cone_height*ir,[for(ang=lerpn(0,360,n,endpoint=false))
each zrot(ang+ang_ofs,cyl_proj(factor*or,profile))]);
safebottom = min(min(column(topinner,2)), min(column(topouter,2))) - base - (crop?1:0);
botinner = [for(val=topinner) [val.x,val.y,safebottom]];
botouter = [for(val=topouter) [val.x,val.y,safebottom]];
vert = [topouter, topinner, botinner, botouter];
datamin = min(min(column(topinner,2)), min(column(topouter,2)));
anchors = [
named_anchor("teeth_bot", [0,0,bottom], DOWN)
];

2
vectors.scad
View file

@ -47,7 +47,7 @@
// is_vector([],zero=false); // Returns false
function is_vector(v, length, zero, all_nonzero=false, eps=EPSILON) =
is_list(v) && len(v)>0 && []==[for(vi=v) if(!is_finite(vi)) 0]
&& (is_undef(length) || len(v)==length)
&& (is_undef(length) || (assert(is_num(length))len(v)==length))
&& (is_undef(zero) || ((norm(v) >= eps) == !zero))
&& (!all_nonzero || all_nonzero(v)) ;