PCF piping files from and to pipe runs

The bore written for a pipe section.

bore = nominal diameter for the pipe size, else outside diameter to 1 decimal

A size in the table gives its whole-number nominal diameter in millimeters. Any other section gives its outside diameter rounded with toFixed(1).

const bore = (sec) => (sec ? dnOfNps(sec.nps) ?? +(sec.od ?? sec.w ?? 0).toFixed(1) : 0);

The corner point and turn angle written for an elbow or bend.

corner = p₀ + d₁ × R tan(θ ÷ 2); angle = θ × 180 ÷ π to 2 decimals

The corner is one 64-bit expression from the bend's start point, incoming direction, radius and angle. The angle is rounded to 0.01 degree with toFixed(2) before it is written; the choice between elbow and bend uses the unrounded angle.

const T = part.R * Math.tan(part.th / 2), corner = add(part.p0, mul(part.d1, T)), deg = (part.th * 180) / Math.PI;
comps.push({ type: Math.abs(deg - 90) < 1 ? 'ELBOW' : 'BEND', ends: [end(part.p0, b), end(part.p1, b)], centre: corner, branch: null, at: null, skey: 'ELBW', angle: +deg.toFixed(2), attrs: [], line: 0 });

The corner of an imported elbow from the legs before and after it.

s = (b e − c d) ÷ (a c − b²), t = (a e − b d) ÷ (a c − b²); corner = midpoint of the two closest points

For unit directions the denominator is the squared sine of the angle between the legs; under 1e-9 the legs count as parallel and the file's own center point is used. The two closest points must lie within 2 mm of each other, an absolute limit.

function lineMeet(p, d, q, e) {
  // the point where line (p, d) passes nearest to line (q, e) — their meeting point for legs that lie in one plane
  const w = sub(p, q), a = dot(d, d), b = dot(d, e), c = dot(e, e), dd = dot(d, w), ee = dot(e, w), den = a * c - b * b;
  if (Math.abs(den) < 1e-9) return null;
  const s = (b * ee - c * dd) / den, t = (a * ee - b * dd) / den;
  const P1 = add(p, mul(d, s)), P2 = add(q, mul(e, t));
  return len(sub(P1, P2)) < 2 ? mul(add(P1, P2), 0.5) : null;
}

The distance along an imported run to the point nearest a valve.

s = Σ earlier leg lengths + clamp((p − a) · d, 0, L), rounded to 1 decimal

Leg lengths are Math.hypot values added in order. The result is rounded to 0.1 mm with toFixed(1), and that rounded value is the valve's position in the new run.

function along(pts, p) {
  let best = { off: Infinity, s: 0 }, run = 0;
  for (let i = 1; i < pts.length; i++) {
    const a = pts[i - 1], b = pts[i], L = len(sub(b, a)), d = unit(sub(b, a));
    const t = Math.max(0, Math.min(L, dot(sub(p, a), d))), q = add(a, mul(d, t)), off = len(sub(p, q));
    if (off < best.off) best = { off, s: run + t };
    run += L;
  }
  return +best.s.toFixed(1);
}

The standard nominal diameter nearest to a bore that is not a standard size.

nearest = table value with the least |value − bore|

A search over the table's whole-number diameters that starts from 50; on a tie the value found first is kept. The differences are of whole or near-whole millimeters, so no digits are at stake.

const nearestDn = (dn) => Object.values(NPS_DN).reduce((b, v) => (Math.abs(v - dn) < Math.abs(b - dn) ? v : b), 50);