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Merged
adrianVmariano merged 3 commits into from
Feb 22, 2026
Merged

teardrop bugfix and realign correction #1917

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cd70eef
teardrop bugfix and realign correction for ellipse
adrianVmariano Feb 21, 2026
2daff5c
hex_grid correction
adrianVmariano Feb 22, 2026
2770071
fix realign for cyl() and tube; fix torus bug()
adrianVmariano Feb 22, 2026
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2 changes: 1 addition & 1 deletion linalg.scad
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Original file line number Diff line number Diff line change
Expand Up @@ -128,7 +128,7 @@ function echo_matrix(M,description,sig=4,sep=1,eps=1e-9) =
let(
horiz_line = 8213,
matstr = _format_matrix(M,sig=sig,sep=sep,eps=eps),
separator = chf(repeat(horiz_line,10)),
separator = chr(repeat(horiz_line,10)),
dummy=echo(str(separator,is_def(description) ? str(" ",description) : ""))
[for(row=matstr) echo(row)]
)
Expand Down
56 changes: 34 additions & 22 deletions shapes2d.scad
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Original file line number Diff line number Diff line change
Expand Up @@ -357,14 +357,21 @@ module circle(r, d, points, corner, anchor=CENTER, spin=0) {
// attachments to the ellipse will retain their dimensions, whereas scaling a circle with attachments will also scale the attachments.
// If you set `uniform` to true then you will get a polygon with congruent sides whose vertices lie on the ellipse. The `circum` option
// requests a polygon that circumscribes the requested ellipse (so the specified ellipse will fit into the resulting polygon). Note that
// you cannot gives `circum=true` and `uniform=true`.
// you cannot gives `circum=true` and `uniform=true`.
// .
// When the `realign` parameter is false the shape appears with its first vertex on the X+ axis and points moving counterclockwise from there.
// If `realign` is true then the midpoint of an edge is on the X+ axis and the first point of the polygon is below the X+ axis. By default,
// `realign` is false when `circum` is false and true if `circum` is true. This means that when `$fn` is a multiple of four the ellipse always
// has exactly correct dimensions on the X and Y axes regardless of the setting for circum, and it also means that circles match "octa"
// style spheroids on any of the coordinate planes. For circles, `realign` just rotates the circle. But for noncircular ellipses with `uniform=true`
// setting `realign=true` completely changes the shape compared to `realign=false`.
// Arguments:
// r = Radius of the circle or pair of semiaxes of ellipse
// ---
// d = Diameter of the circle or a pair giving the full X and Y axis lengths.
// realign = If false starts the approximate ellipse with a point on the X+ axis. If true the midpoint of a side is on the X+ axis and the first point of the polygon is below the X+ axis. This can result in a very different polygon when $fn is small. Default: false
// uniform = If true, the polygon that approximates the circle will have segments of equal length. Only works if `circum=false`. Default: false
// circum = If true, the polygon that approximates the circle will be upsized slightly to circumscribe the theoretical circle. If false, it inscribes the theoretical circle. If this is true then `uniform` must be false. Default: false
// d = Diameter of the circle or a pair giving the width and height of the ellipse.
// realign = If false a vertex is on the X+ axis. If true the midpoint of an edge is on the X+ axis. Default: false if `circum=false` and true if `circum=true`
// uniform = If true, the polygon that approximates the ellipse will have segments of equal length. Only supported when `circum=false`. Default: false
// circum = If true, the polygon that approximates the ellipse will circumscribe the ideal ellipse. If false, it inscribes the ideal ellipse. If this is true then `uniform` must be false. Default: false
// anchor = Translate so anchor point is at origin (0,0,0). See [anchor](attachments.scad#subsection-anchor). Default: `CENTER`
// spin = Rotate this many degrees around the Z axis after anchor. See [spin](attachments.scad#subsection-spin). Default: `0`
// Example(2D): By Radius
Expand Down Expand Up @@ -425,10 +432,13 @@ module circle(r, d, points, corner, anchor=CENTER, spin=0) {
// stroke([ellipse(r=r, $fn=5,realign=false,uniform=true)],width=0.2,color="red");
// }
// }
module ellipse(r, d, realign=false, circum=false, uniform=false, anchor=CENTER, spin=0)
module ellipse(r, d, realign, circum=false, uniform=false, anchor=CENTER, spin=0)
{
realign = assert(is_bool(circum))
default(realign,circum);
r = force_list(get_radius(r=r, d=d, dflt=1),2);
dummy = assert(is_vector(r,2) && all_positive(r), "Invalid radius or diameter for ellipse");
dummy = assert(is_bool(realign))
assert(is_vector(r,2) && all_positive(r), "Invalid radius or diameter for ellipse");
sides = segs(max(r));
sc = circum? (1 / cos(180/sides)) : 1;
rx = r.x * sc;
Expand All @@ -440,14 +450,12 @@ module ellipse(r, d, realign=false, circum=false, uniform=false, anchor=CENTER,
}
else if (rx < ry) {
xscale(rx/ry) {
realign = circum? !realign : realign;
zrot(realign? 180/sides : 0) {
circle(r=ry, $fn=sides);
}
}
} else {
yscale(ry/rx) {
realign = circum? !realign : realign;
zrot(realign? 180/sides : 0) {
circle(r=rx, $fn=sides);
}
Expand Down Expand Up @@ -505,14 +513,15 @@ function _ellipse_refine_realign(a,b,N, _theta=[],i=0) =
)
_ellipse_refine_realign(a,b,N,adjusted, i+1);



function ellipse(r, d, realign=false, circum=false, uniform=false, anchor=CENTER, spin=0) =
function ellipse(r, d, realign, circum=false, uniform=false, anchor=CENTER, spin=0) =
assert(is_bool(circum))
let(
r = force_list(get_radius(r=r, d=d, dflt=1),2),
sides = segs(max(r)),
realign = circum? !realign : realign
realign = default(realign,circum)
)
assert(is_bool(realign))
assert(all_positive(r), "All components of the radius must be positive.")
uniform
? assert(!circum, "Circum option not allowed when \"uniform\" is true")
Expand Down Expand Up @@ -1152,9 +1161,9 @@ module trapezoid(h, w1, w2, ang, shift, chamfer=0, rounding=0, flip=false, ancho
// d/od = The diameter to the tips of the star.
// id = The diameter to the inner corners of the star.
// step = Calculates the radius of the inner star corners by virtually drawing a straight line `step` tips around the star. 2 <= step < n/2
// realign = If false, vertex 0 will lie on the X+ axis. If true then the midpoint of the last edge will lie on the X+ axis, and vertex 0 will be below the X axis. Default: false
// align_tip = If given as a 2D vector, rotates the whole shape so that the first star tip points in that direction. This occurs before spin.
// align_pit = If given as a 2D vector, rotates the whole shape so that the first inner corner is pointed towards that direction. This occurs before spin.
// realign = If false, the shape starts with a star point on the X+ axis. If true then a star pit (the last vertex) will be on the X+ axis and the first vertex will be a point below the X+ axis. Default: false
// align_tip = If given as a 2D vector, rotates the whole shape so that the first star tip points in that direction. This occurs before spin. If realign is true this aligns a pit instead.
// align_pit = If given as a 2D vector, rotates the whole shape so that the first inner corner is pointed towards that direction. This occurs before spin. If realign is true this aligns a tip instead.
// anchor = Translate so anchor point is at origin (0,0,0). See [anchor](attachments.scad#subsection-anchor). Default: `CENTER`
// spin = Rotate this many degrees around the Z axis after anchor. See [spin](attachments.scad#subsection-spin). Default: `0`
// atype = Choose "hull" or "intersect" anchor methods. Default: "hull"
Expand Down Expand Up @@ -1348,9 +1357,12 @@ module jittered_poly(path, dist=1/512) {
// the result will be the full, untruncated shape. You can set `cap_h` smaller than the radius to produce a truncated circle. The segments of the round section of the teardrop
// are the same as a circle or cylinder with matching `$fn` when rotated 90 degrees. The number of facets in the teardrop is only approximately
// equal to `$fn`, and may also change if you set `realign=true`, which adjusts the facets so the bottom of the teardrop has a flat base.
// If `$fn` is a multiple of four then the teardrop will reach its extremes on all four axes. The circum option
// produces a teardrop that circumscribes the circle; in this, `realign=true` produces a teardrop that meets its internal extremes
// on the axes. You can add a bottom corner using the `bot_corner` parameter, which specifies the length that the corner protrudes from the ideal circle.
// If `$fn` is a multiple of four then the teardrop will always reach its extremes on all four axes. The `circum` option
// produces a teardrop that circumscribes the circle. Unlike {{cyl()}} and {{ellipse()}}, the default for `realign` is always false for teardrops. This is to
// optimize for 3d printing, where it's best to have a corner at the bottom when `circum=true` to ensure space for the hole. To be certain of sufficient
// space you can add a bottom corner using the `bot_corner` parameter, which specifies the length that the corner protrudes from the ideal circle.
// .
// When `circum` and `realign` have the same values a teardrop and {{cyl()}} or {{ellipse()}} will have edges that match each other.
// Usage: As Module
// teardrop2d(r/d=, [ang], [cap_h], [circum=], [realign=], [bot_corner=]) [ATTACHMENTS];
// Usage: As Function
Expand All @@ -1363,7 +1375,7 @@ module jittered_poly(path, dist=1/512) {
// d = diameter of circular portion of bottom. (Use instead of r)
// circum = if true, create a circumscribing teardrop. Default: false
// bot_corner = create a bottom corner the specified distance below the given radius. Default: 0
// realign = if true, change whether bottom of teardrop is a point or a flat. Default: false
// realign = if true, bottom of teardrop is flat; if false, bottom of teardrop is a point. Default: false
// anchor = Translate so anchor point is at origin (0,0,0). See [anchor](attachments.scad#subsection-anchor). Default: `CENTER`
// spin = Rotate this many degrees around the Z axis after anchor. See [spin](attachments.scad#subsection-spin). Default: `0`
// Example(2D): Typical Shape
Expand Down Expand Up @@ -1426,7 +1438,7 @@ function teardrop2d(r, ang=45, cap_h, d, circum=false, realign=false, anchor=CEN
fullcircle = ellipse(r=r, realign=realign, circum=circum,spin=90),

// Chose the point on the circle that is lower than the cap but also creates a segment bigger than
// seglen/skipfactor so we don't have a teeny tiny segment at the end of the cap, except for the hexagoin
// seglen/skipfactor so we don't have a teeny tiny segment at the end of the cap, except for the hexagon
// case which is treated specially
skipfactor = len(fullcircle)==6 ? 15 : 3,
path = !circum ?
Expand All @@ -1452,7 +1464,7 @@ function teardrop2d(r, ang=45, cap_h, d, circum=false, realign=false, anchor=CEN
[
cap[0],
p,
each select(fullcircle,i+1,-i-1-(realign!=circum?1:0)),
each select(fullcircle,i+1,-i-1-(realign==true && circum==true?1:0)),
xflip(p),
if(_extrapt || !pointycap) xflip(cap[0])
]
Expand Down
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