frac function? Edit: Solved! Use mod 1! about libfive HOT 4 CLOSED

You can use %, the modulo operator!
Though note that it can produce some pretty glitchy SDFs, due to the completely abrupt discontinuities; you really might prefer using a twirl after all. (I get use out of %, but only in contexts where there's either plenty of empty space bordering the edges, or the edges always happen to line up smoothly; if you're trying to create an abrupt edge, modulo can't actually do that right, because it can't actually describe the 'open' faces that those edges leave behind!)

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This is kind of what I figured (for why something like frac is not included). I'll give twirl a whirl!

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At first I was like, how with modulus? Then I realized .mod(1). It works damn perfect! I've got bolts again!

For anyone that needs it:

const mag = (x, y) => sqrt(x.square().add(y.square()));
const thread = (radius_, screw_) => {
  const [x,y,z] = [X(),Y(),Z()];
  const radius = Value(radius_);
  const screw = Value(screw_);
  const rad = mag(x,y).sub(radius);
  const th = (
    rad.sub(
      abs(
       z.mul(screw).sub(atan2(y)(x)).div(Math.PI / 2)
         .mod(1)
         .sub(0.5)
      ).div(screw)
    )
  );
  return th;
};

const bolt = (diameter, height, pitch) =>
  thread(diameter / 2, pitch)
  .intersection(cylinder(diameter + pitch, height));

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P.S. The twirl series of functions, while do twirl, do not twirl uniformly across the surface. Just a warning to anyone who uses them. They won't look like the twirling shown in my screenshot using my SDF.

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