diff --git a/shapes2d.scad b/shapes2d.scad index a948c197..230a63bd 100644 --- a/shapes2d.scad +++ b/shapes2d.scad @@ -1327,20 +1327,21 @@ module jittered_poly(path, dist=1/512) { // Topics: Shapes (2D), Paths (2D), Path Generators, Attachable // See Also: teardrop(), onion(), keyhole() // Description: -// When called as a module, makes a 2D teardrop shape. Useful for extruding into 3D printable holes as it limits overhang to 45 degrees. 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 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`. +// When called as a module, makes a 2D teardrop shape. Useful for extruding into 3D printable holes as it limits overhang to a desired angle. +// Uses "intersect" style anchoring. +// The cap_h parameter truncates the top of the teardrop at the specified distance from the center. If cap_h is taller than the untruncated form then +// the result will be the full, untruncated shape. The segments of the round section of the teardrop +// the same as a circle or cylinder when rotated 90 degrees. (Note that this agreement is poor when `$fn=6` or `$fn=7`.) +// The number of facets is only approximately equal to `$fn`, and may also change if you set `realign=true`, which produces a flat base on the teardrop. // If `$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. -// When called as a function, returns a 2D path to for a teardrop shape. -// +// on the axes. To ensure sufficient room in 3d printing applications a bottom corner may also be desirable. You can add this using +// the `bot_corner` parameter, which specifies the length that the corner protrudes from the ideal circle. +// When called as a function, returns a 2D path for the shape, starting at the top corner or top right corner. // Usage: As Module -// teardrop2d(r/d=, [ang], [cap_h]) [ATTACHMENTS]; +// teardrop2d(r/d=, [ang], [cap_h], [circum=], [realign=], [bot_corner=]) [ATTACHMENTS]; // Usage: As Function -// path = teardrop2d(r|d=, [ang], [cap_h]); -// +// path = teardrop2d(r|d=, [ang], [cap_h], [circum=], [realign=], [bot_corner=]); // Arguments: // r = radius of circular part of teardrop. (Default: 1) // ang = angle of hat walls from the Y axis (half the angle of the peak). (Default: 45 degrees) @@ -1348,19 +1349,22 @@ 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 // 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 // teardrop2d(r=30, ang=30); // Example(2D): Crop Cap // 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, circum=false, realign=false, anchor=CENTER, spin=0) +// Example(2D): Add bottom corner. Here the bottom corner is quite large. Guidance for 3d printing suggests that `bot_corner` should equal the layer thickness. +// teardrop2d(r=30, cap_h=35, bot_corner=5); + +module teardrop2d(r, ang=45, cap_h, d, circum=false, realign=false, bot_corner=0, anchor=CENTER, spin=0) { - path = teardrop2d(r=r, d=d, ang=ang, circum=circum, realign=realign, cap_h=cap_h); + path = teardrop2d(r=r, d=d, ang=ang, circum=circum, realign=realign, cap_h=cap_h, bot_corner=bot_corner); attachable(anchor,spin, two_d=true, path=path, extent=false) { polygon(path); children(); @@ -1370,9 +1374,32 @@ module teardrop2d(r, ang=45, cap_h, d, circum=false, realign=false, anchor=CENTE // _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, circum=false, realign=false, anchor=CENTER, spin=0, _extrapt=false) = +function teardrop2d(r, ang=45, cap_h, d, circum=false, realign=false, anchor=CENTER, spin=0, bot_corner=0, _extrapt=false) = + let( + r = get_radius(r=r, d=d, dflt=1) + ) + bot_corner!=0 ? + assert(all_positive([bot_corner]), "bot_corner must be nonnegative") + let( + path = teardrop2d(r=r,ang=ang, cap_h=cap_h, circum=circum, realign=realign), + corner = -r-bot_corner, + alpha = acos(r/corner), + joint = r*[sin(alpha),cos(alpha)], + table = [[0,corner],joint], + halfpath = [for(pt=path) if (pt.x>=0) + let(proj=lookup(pt.x,table)) + pt.x>joint.x || pt.y>0 || pt.y<=proj ? pt : [pt.x,proj]], + fullpath = deduplicate( + [ + each halfpath, + if (last(halfpath).x>0) [0,corner], + each reverse(xflip(halfpath)) + ], closed=!_extrapt + ) + ) + reorient(anchor,spin,two_d=true, path=fullpath, p=fullpath, extent=false) + : let( - r = get_radius(r=r, d=d, dflt=1), minheight = r*sin(ang), maxheight = r/sin(ang), //cos(90-ang), pointycap = is_undef(cap_h) || cap_h>=maxheight