////////////////////////////////////////////////////////////////////// // LibFile: hooks.scad // Functions and modules for creating hooks and hook like parts. // At the moment only one part is supported, a ring hook. // Includes: // include // include // FileGroup: Parts // FileSummary: Hooks and hook-like parts. ////////////////////////////////////////////////////////////////////// // Module: ring_hook() // Synopsis: A hook with a circular hole or attached cylinder // SynTags: Geom // Topics: Parts // See Also: prismoid(), rounded_prism(), ycyl() // Usage: // ring_hook(base_size, hole_z, or, od=, [ir=], [hole=], [rounding=], [fillet=], [hole_rounding=], [anchor=], [spin=], [orient=]) // Description: // Form a part that attaches a loop hook with a cylindrical hole a specified distance away from its mount point. // You specify a rectangle defining the base a hole diameter or radius, and `hole_z`, a distance from the base to the hole. // You can set the hole diameter to zero to create a solid paddle with no hole. // . // In order to calculate a tangent where the base joins the cylinder, // the lower corners of the base must be outside the cylinder (see Example 3). This scenario occurs when // the base is narrower than the Y-cylinder and hole_z is less than Y-cylinder radius. Also, hole_z must // be large enough to accommodate hole rounding and base rounding. // . // The roundings use `$fn`, `$fa` and `$fs`, but if you want to explicitly control the outer shape of the hook // you can separately specify a facet count for the curved portion using `outside_segments`. // Arguments: // base_size = 2-vector specifying x and y sizes of the base // hole_z = distance in the z direction from the base to the center of the hole // or = radius of the cylindrical portion of the part (or zero to create no hole) // --- // od = diameter of the cylindrical portion of the part // ir / id = optional radius/diameter of the center hole // wall = set thickness of the wall around the central hole // hole = Set to "circle" for a circle hole, "D" for a D-shaped (semicircular) hole or a path to create a custom hole. Default: "circle" // rounding = rounding of the vertical-ish edges of the prismoid and the exposed edges of the cylinder. Default: 0 // fillet = base fillet. If negative produces a rounded edge instead of a fillet. Default: 0 // hole_rounding = rounding of the optional hole. Default: 0 // outside_segments = number of segments to use for the outer curved part of the hook instead of using `$fn`, `$fa` and `$fs`. // 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. See [spin](attachments.scad#subsection-spin). Default: 0 // orient = Vector to rotate top towards. See [orient](attachments.scad#subsection-orient). Default: UP // Named anchors: // hole_front = front, center of the cylindrical portion of the part (same as the part FRONT if hole_z=or) // hole_back = back, center of the cylindrical portion of the part (same as the part BACK if hole_z=or) // tangent_right = right side anchor at the point where the prismoid merges with Y-cylinder, at y=0 // tangent_left = left side anchor at the point where the prismoid merges with Y-cylinder, at y=0 // Attachable Parts: // "inside" = The inner hole (not defined if there is no hole) // Example: Ring connector // ring_hook([50, 10], 25, 25, ir=20); // Example: Widen the base, add base fillet, no hole // $fa=4;$fs=1/2; // ring_hook([70, 10], 25, or=25, ir=0, fillet=3, rounding=1.5); // Example: Narrow base // $fa=4;$fs=1/2; // ring_hook([40, 10], 25, or=25, ir=0, fillet=3, rounding=1.5); // Example: Negative fillet value // $fa=4;$fs=1/2; // ring_hook([40, 10], 25, or=25, ir=0, fillet=-3, rounding=1.5); // Example(3D,VPR=[90,0,0]): If the base is narrower than the cylinder diameter then its corners have to be outside the cylinder for this shape to be defined because it requires a tangent line to the cylinder. This example shows a valid base corner point in blue. An invalid corner point appears in red: no tangent to the circle exists through the red point. // hole_z = 20; // base_size = [40, 10]; // outer_radius = 25; // ring_hook(base_size, hole_z, outer_radius, ir=0); // up(hole_z) color("blue", 0.25) ycyl(r=outer_radius, h=base_size.y + 2); // right(0.5*base_size.x) color("blue") ycyl(r=1, h=base_size.y + 2, $fn=12); // right(0.3*base_size.x) color("red") ycyl(r=1, h=base_size.y + 2, $fn=12); // Example(3D,VPR=[60.60,0.00,62.10]): Through hole can be specified using or/od, ir/id, wall variables. All of these are equivalent. // ydistribute(spacing = 25) { // ring_hook([50, 10], 40, or=25, ir=20); // ring_hook([50, 10], 40, 25, wall=5); // ring_hook([50, 10], 40, wall=5, ir=20); // ring_hook([50, 10], 40, od=50, id=40); // ring_hook([50, 10], 40, od=50, wall=5); // ring_hook([50, 10], 40, wall=5, id=40); // } // Example: Semi-circular through hole (a D-hole): // ring_hook([50, 10], 12, 25, ir=15, hole="D", rounding=3, hole_rounding=3, fillet=2); // Example: hole_z must be greater than 0 with no hole or with hole="D". Here hole_z is 1, close to the minimum value of zero. // xdistribute(spacing=60){ // ring_hook([50, 10], 1, 25, ir=0); // ring_hook([50, 10], 1, 25, ir=15, hole="D"); // } // Example: hole_z must be greater than ir + hole_rounding + fillet when hole="circle". Here hole_z is only 1 larger than the minimum. // $fs=1;$fa=5; // ring_hook([50, 10], hole_z=27, or=25, ir=20, hole_rounding=3, fillet=3); // Example: Rounding all edges // ring_hook([50, 10], 40, 25, ir=15, rounding=5, hole_rounding=5, fillet=5); // Example: Giving an arbitrary path for the hole, in this case an octagon to make the object printable without support. // ring_hook([50, 20],30, 25, hole=octagon(side=10,realign=true), hole_rounding=3, rounding=4) ; // Example: Using `outside_segments` // $fs=.2;$fa=2; // ring_hook(base_size=[40,10],hole_z=14, od=29,hole=rect(12), // rounding=1,hole_rounding=1,fillet=1,outside_segments=3); // Example(3D,Med): The ring_hook includes 4 custom anchors: front & back at the center of the cylinder component and left & right at the tangent points. // ring_hook([55, 10], 12, 25, ir=0) show_anchors(std=false); // Example: Use the custom anchor to place a screw hole // include // diff() // ring_hook([20, 10], 15, 7, ir=0, fillet=3) // attach("hole_front") // screw_hole("M5", length=20, head="socket", atype="head", anchor=TOP, orient=UP); // Example: Use the custom anchor to create a cylindrical extension instead of a hole // $fs=1;$fa=2; // ring_hook([30,10], hole_z=17, or=10, ir=0, rounding=1.5) // attach("hole_front", BOT) // cyl(d=10, h=14, rounding1=-2, rounding2=2); // Example(3D,VPR=[83.70,0.00,29.20]): Use the "inner" part to create a bar across the hole: // diff() // ring_hook([50, 20],30, 25, ir=10, hole_rounding=3, rounding=4) // attach_part("inner") // prism_connector( circle(3, $fn=16), // parent(), LEFT, // parent(), RIGHT, fillet=1); function ring_hook(base_size, hole_z, or, ir, od, id, wall, hole="circle", rounding=0, fillet=0, hole_rounding=0, outside_segments, anchor=BOTTOM, spin=0, orient=UP) = no_function("ring_hook"); module ring_hook(base_size, hole_z, or, ir, od, id, wall, hole="circle", rounding=0, fillet=0, hole_rounding=0, outside_segments, anchor=BOTTOM, spin=0, orient=UP) { or_tmp = get_radius(r=or, d=od); ir_tmp = get_radius(r=ir, d=id); dummy = assert(is_path(hole) || num_defined([ir_tmp, or_tmp, wall])==2, "Must define exactly two of or/od, ir/id and wall (unless you give a custom hole)") assert(!is_path(hole) || num_defined([ir_tmp, wall])==0, "Canot define ir/id or wall with a custom hole"); ir = is_path(hole) ? 0 : is_def(ir_tmp) ? ir_tmp : or_tmp - wall; or = is_def(or_tmp) ? or_tmp : ir + wall; dummy2 = assert(is_path(hole) || ir <= or, "Hole doesn't fit or wall size is negative") assert(sqrt((0.5*base_size.x)^2 + hole_z^2) > or, "Base corners must be outside the cylinder") assert(in_list(hole,["circle","D"]) || is_path(hole,2), "hole must be \"circle\", \"D\" or a 2d path") assert(is_undef(outside_segments) || outside_segments>=2, "outside_segments must be at least 2") assert(all_nonnegative([hole_rounding]), "hole_rounding must be greater than or equal to 0"); if (ir > 0 && hole=="circle") assert(ir + hole_rounding < hole_z-fillet,str("ir + hole_rounding must be less than ",hole_z-fillet)); z_offset = (hole_z - or)/2; tangents = circle_point_tangents( r=or, cp=[0,hole_z], pt=[0.5*base_size.x, 0]); // we want the tangent with the larger y value tangent = tangents[0].y > tangents[1].y ? tangents[0] : tangents[1]; // anchor calcs angle = atan((tangent.x - 0.5*base_size.x)/tangent.y); top_x = 0.5*base_size.x + (hole_z + or)*tan(angle); // when or > 0.5*base_size.x, need to move the anchor // use x^2 + y^2 = r^2, x = sqrt(r^2 - y^2) delta_y = z_offset; mid_x = sqrt(or^2 - delta_y^2); h = hole_z + or; w = base_size.y; size = [base_size.x, w]; size2 = [2*top_x, w]; right_tang_dir = unit([tangent.x, 0, tangent.y-hole_z]); left_tang_dir = unit([-tangent.x,0, tangent.y-hole_z]); prism_steps = segs(max(rounding,abs(fillet)),90); hole_rounding_steps = segs(hole_rounding,90); anchors = [ named_anchor("hole_front", [0, -w/2, z_offset], FRONT, 0), named_anchor("hole_back", [0, w/2, z_offset], BACK, 180), named_anchor("tangent_right", [tangent[0], 0, tangent[1] - hole_z + z_offset], right_tang_dir, _compute_spin(right_tang_dir,UP,BACK)), named_anchor("tangent_left", [-tangent[0], 0, tangent[1] - hole_z + z_offset], left_tang_dir, _compute_spin(left_tang_dir,UP,BACK)), ]; override = [ for (i = [-1, 1], j=[-1:1], k=[0:1]) if (k==0 && j!=0 && or > 0.5*base_size.x) [[i, j, 0], [mid_x*unit([i, 0, 0]) + 0.5*base_size.y*unit([0, j, 0])]] else if (k==0 && or > 0.5*base_size.x) [[i, 0, 0], [mid_x*unit([i, 0, 0])]] else if (k==1 && j==0) [[i, 0, 1], [or*sin(45)*unit([i, 0, 0]) + (z_offset + or*sin(45))*unit([0, 0, k])]] else if (k==1) [[i, j, 1], [or*sin(45)*unit([i, 0, 0]) + 0.5*base_size.y*unit([0, j, 0]) + (z_offset + or*sin(45))*unit([0, 0, k])]] ]; hole = is_path(hole) ? hole : hole=="D" ? arc(angle=180, r=ir, rounding=hole_rounding, wedge=true) : ir > 0 ? circle(ir) : undef; parts = is_undef(hole) ? undef :[ define_part("inner", attach_geom( region=[ymove(z_offset,hole)], l=size.y), T=xrot(90), inside=true) ]; attachable( anchor, spin, orient, size=point3d(size,h), size2=size2, anchors=anchors, override=override, parts=parts ) { down(h/2) difference() { union() { startangle = atan2(tangent.y-hole_z, tangent.x); endangle = posmod(atan2(tangent.y-hole_z, -tangent.x),360); steps = 1+first_defined([outside_segments,segs(or,endangle-startangle)]); delta = (endangle-startangle)/(steps-1); profile = rounding == 0 ? [[or,0,-base_size.y/2],[or,0,base_size.y/2]] : let( // rounded prism roundings are computed on top face, so cos() correction is needed // to get them to align properly bez = _smooth_bez_fill([//[or-rounding*(startangle>0?cos(startangle):1),0,-base_size.y/2], [or-rounding,0,-base_size.y/2], [or,0,-base_size.y/2], [or,0,-base_size.y/2+rounding]],0.92), pts = bezier_curve(bez,splinesteps=prism_steps) ) concat(pts, reverse(zflip(pts))); toplist = [ [for(pt=profile) [0,-or,pt.z]], if (startangle<0) move(-[tangent.x-base_size.x/2,tangent.y] ,zrot(startangle, profile)), for(angle = lerpn(startangle, endangle, steps)) zrot(angle, profile), if (startangle<0) move(-[-tangent.x+base_size.x/2,tangent.y] ,zrot(endangle, profile)), ]; intersection(){ up(hole_z)xrot(90) vnf_vertex_array(transpose(toplist),caps=true,col_wrap=true,reverse=true,triangulate=true); up(abs(fillet))cuboid([max(base_size.x,2*or),w+1, or+hole_z+1],anchor=BOT); } // When base is outside the circle the base needs to be clipped so the roundings don't interfere // This mask does this clipping maskpath2 = [zrot(startangle,[or+1,0,0]), zrot(startangle,[or-rounding, 0, 0]), zrot(startangle+delta, [or-rounding-.1, 0, 0]), ]; maskpath = up(hole_z,xrot(90, [each maskpath2, [maskpath2[0].x, maskpath2[0].x*tan(startangle+delta),0] ])); difference(){ rounded_prism( rect(base_size), rect( [ 2*tangent.x, w ] ), h=tangent.y, joint_bot=-fillet, joint_sides=rounding, k_sides=0.92, k_bot=0.92, anchor=BOT,splinesteps=prism_steps); if (startangle>0) xflip_copy() vnf_vertex_array([fwd(w/2+1, maskpath), back(w/2+1, maskpath)], col_wrap=true,caps=true,reverse=true); } } if (is_def(hole)) { up(hole_z) prism_connector( hole, parent(), FRONT, parent(), BACK, fillet=hole_rounding, n=hole_rounding_steps); } } children(); } }