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fix teardrop for extents to make proper cuboids

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This commit is contained in:
Adrian Mariano
2022-11-05 16:25:37 -04:00
parent 9adcf15104
commit 8cd43a6637
2 changed files with 62 additions and 21 deletions
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64
shapes2d.scad
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@@ -1191,12 +1191,16 @@ module jittered_poly(path, dist=1/512) {
// Description:
// Makes a 2D teardrop shape. Useful for extruding into 3D printable holes. Uses "intersect" style anchoring.
// The cap_h parameter truncates the top of the teardrop. If cap_h is taller than the untruncated form then
// the result will be the full, untruncated shape.
// the result will be the full, untruncated shape. The segments of the bottom section of the teardrop are
// calculated to be the same as a circle or cylinder when rotated 90 degrees. (Note that this agreement is poor when `$fn=6` or `$fn=7`.
// 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 case set `realign=true` to get a teardrop that meets its internal extremes
// on the axes.
//
// Usage: As Module
// teardrop2d(r/d=, [ang], [cap_h]) [ATTACHMENTS];
// Usage: As Function
// path = teardrop2d(r/d=, [ang], [cap_h]);
// path = teardrop2d(r|d=, [ang], [cap_h]);
//
// Topics: Shapes (2D), Paths (2D), Path Generators, Attachable
//
@@ -1208,6 +1212,8 @@ module jittered_poly(path, dist=1/512) {
// cap_h = if given, height above center where the shape will be truncated.
// ---
// d = diameter of circular portion of bottom. (Use instead of r)
// circum = if true, create a circumscribing teardrop. Default: false
// realign = if true, change whether bottom of teardrop is a point or a flat. 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`
//
@@ -1217,9 +1223,9 @@ module jittered_poly(path, dist=1/512) {
// teardrop2d(r=30, ang=30, cap_h=40);
// Example(2D): Close Crop
// teardrop2d(r=30, ang=30, cap_h=20);
module teardrop2d(r, ang=45, cap_h, d, anchor=CENTER, spin=0)
module teardrop2d(r, ang=45, cap_h, d, circum=false, realign=false, anchor=CENTER, spin=0)
{
path = teardrop2d(r=r, d=d, ang=ang, cap_h=cap_h);
path = teardrop2d(r=r, d=d, ang=ang, circum=circum, realign=realign, cap_h=cap_h);
attachable(anchor,spin, two_d=true, path=path, extent=false) {
polygon(path);
children();
@@ -1229,20 +1235,54 @@ module teardrop2d(r, ang=45, cap_h, d, anchor=CENTER, spin=0)
// _extrapt = true causes the point to be duplicated so a teardrop with no cap
// has the same point count as one with a cap.
function teardrop2d(r, ang=45, cap_h, d, anchor=CENTER, spin=0, _extrapt=false) =
function teardrop2d(r, ang=45, cap_h, d, circum=false, realign=false, anchor=CENTER, spin=0, _extrapt=false) =
let(
r = get_radius(r=r, d=d, dflt=1),
ang2=90-ang,
minheight = r*sin(ang),
maxheight = r/cos(ang2)
maxheight = r/sin(ang), //cos(90-ang),
pointycap = is_undef(cap_h) || cap_h>=maxheight
)
assert(is_undef(cap_h) || cap_h>=minheight, str("cap_h cannot be less than ",minheight," but it is ",cap_h))
let(
firstpt = is_undef(cap_h) || cap_h>=maxheight ? [[0,maxheight]]
: [[(maxheight-cap_h)*tan(ang), cap_h]],
lastpt = !_extrapt && (is_undef(cap_h) || cap_h>=maxheight) ? [] : [[-firstpt[0].x,firstpt[0].y]],
path = concat(firstpt, arc(angle=[ang, -180-ang], r=r), lastpt)
) reorient(anchor,spin, two_d=true, path=path, p=path, extent=false);
cap = [
pointycap? [0,maxheight] : [(maxheight-cap_h)*tan(ang), cap_h],
r*[cos(ang),sin(ang)]
],
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/3 so we don't have a teeny tiny segment at the end of the cap
path = !circum ?
let(seglen = norm(fullcircle[0]-fullcircle[1]))
[
each cap,
for (p=fullcircle)
if (
p.y<last(cap).y-EPSILON
&& norm([abs(p.x)-last(cap).x,p.y-last(cap.y)])>seglen/3
) p,
xflip(cap[1]),
if (_extrapt || !pointycap) xflip(cap[0])
]
: let(
isect = [for(i=[0:1:len(fullcircle)/4])
let(p = line_intersection(cap, select(fullcircle,[i,i+1]), bounded1=RAY, bounded2=SEGMENT))
if (p) [i,p]
],
i = last(isect)[0],
p = last(isect)[1],
ff=echo(isect)
)
[
cap[0],
p,
each select(fullcircle,i+1,-i-1-(realign?1:0)),
xflip(p),
if(_extrapt || !pointycap) xflip(cap[0])
]
)
reorient(anchor,spin, two_d=true, path=path, p=path, extent=false);
// Function&Module: egg()