Manufacturing cost estimate

const c = rates.cnc, allow = c.allowance;
const stock = size.map((s) => s + 2 * allow), stockVol = stock[0] * stock[1] * stock[2];
const stockKg = stockVol * density * 1e-9, removal = stockVol - vol, mrr = c.mrr[matId];
if (!(mrr > 0)) throw Object.assign(new Error('There is no removal rate for "' + matId + '".'), { code: 'invalid_argument', next: ['Give rates.cnc.mrr for it.'] });
const holes = holeCount(part);
const cutMin = removal / mrr * c.finishing, holeMin = holes * c.holeMin, minutes = cutMin + holeMin + c.handling;
rows.push({ id: 'stock', what: 'Stock', amount: stockKg * price, basis: { box: stock.map(r2), volume_mm3: r2(stockVol), kg: r2(stockKg * 1000) / 1000, perKg: price } });
rows.push({ id: 'cutting', what: 'Cutting', amount: cutMin / 60 * c.perHour, basis: { removal_mm3: r2(removal), mrr_mm3_min: mrr, finishing: c.finishing, minutes: r2(cutMin) } });
if (holes) rows.push({ id: 'holes', what: 'Holes', amount: holeMin / 60 * c.perHour, basis: { holes, minutesEach: c.holeMin, minutes: r2(holeMin) } });
rows.push({ id: 'handling', what: 'Handling', amount: c.handling / 60 * c.perHour, basis: { minutes: c.handling } });
unit = rows.reduce((a, r) => a + r.amount, 0);

const printed = vol * p.fill, kg = printed * density * 1e-9, hours = printed / p.mm3PerHour;
rows.push({ id: 'material', what: 'Filament', amount: kg * price, basis: { printed_mm3: r2(printed), fill: p.fill, kg: r2(kg * 1000) / 1000, perKg: price } });
rows.push({ id: 'machine', what: 'Machine time', amount: hours * p.perHour, basis: { hours: r2(hours), mm3PerHour: p.mm3PerHour, perHour: p.perHour } });

const total = unit + job / qty;
const shares = {};
for (const r of rows) shares[r.id] = total > 0 ? r.amount / total : 0;
shares.setup = total > 0 ? (job / qty) / total : 0;
rows.push({ id: 'setup', what: 'Setup, shared', amount: job / qty, basis: { job, qty } });
for (const r of rows) r.amount = r2(r.amount);
notes.push('The rates are placeholders for a typical small shop, not a quote: set your own (they are saved with the part).');
return { process, qty, currency: rates.currency, material: matId, partKg: Math.round(partKg * 1e5) / 1e5, volume_mm3: r2(vol), rows, unit: r2(unit), job: r2(job), total: r2(total), perPartAtQty: r2(total), shares, drivers, notes, rates };

const r2 = (v) => Math.round(v * 100) / 100;

/** Holes the part has: hole features (a pattern of them counts each copy) and circles in the sketches of cut extrusions. */
export function holeCount(part) {
  const byId = new Map(part.features.map((f) => [f.id, f]));
  let n = 0;
  const holes = new Map();
  for (const f of part.features) {
    if (f.suppressed) continue;
    if (f.type === 'hole') holes.set(f.id, 1);
    else if (f.type === 'extrude' && f.op === 'cut') {
      const sk = byId.get(f.sketch)?.sketch;
      if (sk) holes.set(f.id, sk.entities.filter((e) => e.type === 'circle' && !e.construction).length);
    }
  }
  const patterned = new Set();
  for (const f of part.features) {
    if (f.suppressed || (f.type !== 'lpattern' && f.type !== 'cpattern')) continue;
    for (const id of f.seeds || []) if (holes.has(id)) { n += holes.get(id) * (Math.max(1, f.count) - 1); }
  }
  for (const v of holes.values()) n += v;
  return n;
}