// hook designed to hook knots on small diameter cord and be as snagless as possible

// closed hole diameter
cdLoop = 3.1;
// hook slot width
cdHook = 2;
// slot section od
bigD = 20;
// closed hole section od
smallD = 9;
// slot angle
degSlot = 40;
// thickness
thick = 5;
// minkowski sphere radius, fillet rad sort of
filletRad = 2;
// sets side bulge. adds strength and beauty. low value will cause failed print. tested at 0.4
bulbousness = 0.4;
// 40+ faces for print but it makes minkowski very slow in editing
$fn = 45;

// diff for slicing off top bottom and loop hole
difference(){
  //trace sphere for chamfering around union of two cylinders with slot
  minkowski(){
    //two cylinders with a slot cut at around ? degrees
    difference(){
        union(){
          cylinder(d = bigD, thick * bulbousness, center = true);
          // center starts origin, so translate up sin30 and right cos30
          translate([cos(degSlot) * bigD/2, sin(degSlot) * bigD/2, 0]){
              cylinder(d = smallD, thick * bulbousness, center = true);
            }
          }
        // slot:
        translate([50, 0, 0]){
            cube([100, cdHook + 2 * filletRad, 2], center = true);
          }
        // rounded slot pocket:
        cylinder(d = cdHook + 2 * filletRad, 2, center = true);
      } // diff

    sphere(r = filletRad);

    }

  // minus:
  translate([cos(degSlot) *  bigD/2, sin(degSlot) * bigD/2, 0]){
      cylinder(d = cdLoop, 55, center = true);
    }
  for (dir = [-1, 1]) translate([0, 0, dir * (thick / 2 + 1)]){
      cube([99, 99, 2], center = true);
    }
  }