Resources Numerical accuracy

Equality comparisons

Where the code asks whether two decimal numbers are exactly equal. A floating-point result can differ from another in the last digit after a few transformations, so a mesh run through several of them can change the length of an edge, or miss a match. Compare with < or > where a range is meant, and with a documented epsilon where equality is.

316 comparisons to look at
149 files
175 likely to matter (against a decimal, or two computed values)
Scanned November 6, 2026

These are places worth checking, not confirmed bugs. The scan reads how the code is written, not what it is meant to do, so some entries are fine as they are: a test against exactly 0 is often a deliberate guard against dividing by zero. It skips text, counts and indexes, and any comparison it cannot be sure involves decimal numbers, so there are likely more in the code than are listed here.

Against 0 nurbs/construct.js:86 in revolve ModelCraft, PartCraft
```
if (V.len(Z) === 0) fail('nurbs.err.axis');
```
=== in V.len(Z) === 0. Usually fine as a guard against dividing by zero; check it is not meant to catch a near-zero value too. Reviewed: Surfaces from curves: extrude, ruled, revolve and loft, Fitted curves and surfaces: sweeps, networks, Coons patches, offsets, rebuilds and extensions.
Against 0 tools.js:727 in value ModelCraft
```
if (!Number.isFinite(deg) || deg === 0) return false;
```
=== in deg === 0. Usually fine as a guard against dividing by zero; check it is not meant to catch a near-zero value too. Not in the register.
Against 0 tools.js:1138 in pickPoint ModelCraft
```
this.k = 1 / Math.max(len(this.T.localDir(this.n)), 1e-9) === 0 ? 1 : len(this.T.localDir(this.n));
```
=== in 1 / Math.max(len(this.T.localDir(this.n)), 1e-9) === 0. Usually fine as a guard against dividing by zero; check it is not meant to catch a near-zero value too. Not in the register.
Against 0 3dm/earcut.js:52 in filterPoints PartCraft
```
if (!p.steiner && (equals(p, p.next) || area(p.prev, p, p.next) === 0)) {
```
=== in area(p.prev, p, p.next) === 0. Usually fine as a guard against dividing by zero; check it is not meant to catch a near-zero value too. Not in the register.
Against 0 3dm/geom.js:155 in rec PartCraft
```
if (chordDev(pm, pa, pb) > tol || chordDev(q1, pa, pb) > tol || chordDev(q3, pa, pb) > tol || (depth < 2 && dist(pa, pb) === 0 && dist(pm, pa) > tol)) {
```
=== in dist(pa, pb) === 0. Usually fine as a guard against dividing by zero; check it is not meant to catch a near-zero value too. Not in the register.
Against 0 3dm/tess.js:245 in emit PartCraft
```
if (ar === 0) { const n = cross(sub(pos(c), pos(a)), sub(pos(d), pos(a))); if (len(n) === 0) return; }
```
=== in len(n) === 0. Usually fine as a guard against dividing by zero; check it is not meant to catch a near-zero value too. Not in the register.
Against 0 cs-lib-linalg.js:536 in symEigen PartCraft
```
if (scale === 0) {
```
=== in scale === 0. Usually fine as a guard against dividing by zero; check it is not meant to catch a near-zero value too. Reviewed: CraftScript dense linear algebra, CraftScript sparse matrices and direct factorization, CraftScript iterative solvers and sparse eigenvalues.
Against 0 cs-tensor.js:181 in unop PartCraft
```
if (!A.d) return op === 'neg' ? -A.x : op === 'not' ? A.x === 0 : A.x;
```
=== in A.x === 0. Usually fine as a guard against dividing by zero; check it is not meant to catch a near-zero value too. Reviewed: CraftScript array arithmetic.
Against 0 hydrostatics.js:136 in rightingArms PartCraft
```
const M = ang === 0 ? mesh : heeled(mesh, ang);
```
=== in ang === 0. Usually fine as a guard against dividing by zero; check it is not meant to catch a near-zero value too. Reviewed: Hull hydrostatics and righting arms.
Against 0 magnet-study.js:172 in buildJob PartCraft
```
const sources = sp.filter((s, i) => (s.role === 'magnet' && clamp(s.br, 0, 99, 0) > 0) || (s.role === 'coil' && Number(s.current) !== 0));
```
!== in Number(s.current) !== 0. Usually fine as a guard against dividing by zero; check it is not meant to catch a near-zero value too. Reviewed: Magnet study: 2D field, force and torque.
Against 0 tetmesh.js:574 in stuffOnce PartCraft
```
if (c.t === 0) continue;
```
=== in c.t === 0. Usually fine as a guard against dividing by zero; check it is not meant to catch a near-zero value too. Reviewed: Tetrahedral mesh of a part.
Against 0 assets/js/app-devices.js:214 in classifyWheel Shared shell, every app
```
const step = dx === 0 && (legacy || (Number.isInteger(dy) && Math.abs(dy) >= 50));
```
=== in dx === 0. Usually fine as a guard against dividing by zero; check it is not meant to catch a near-zero value too. Not in the register.
Against 0 assets/js/app-devices.js:216 in classifyWheel Shared shell, every app
```
if (dy === 0 && Number.isInteger(dx) && Math.abs(dx) >= 50 && !(mem.until > t)) return 'tilt';
```
=== in dy === 0. Usually fine as a guard against dividing by zero; check it is not meant to catch a near-zero value too. Not in the register.
Against 0 assets/js/app-panels.js:1336 in features Shared shell, every app
```
if (q.x != null && q.y != null && q.x !== 0) f += ',left=' + q.x + ',top=' + q.y;
```
!== in q.x !== 0. Usually fine as a guard against dividing by zero; check it is not meant to catch a near-zero value too. Not in the register.
Against 0 assets/js/calc.js:347 in evalTree Shared shell, every app
```
case '/': if (b.v === 0) fail('domain', 'Division by zero.', 'Check the divisor.'); return { v: a.v / b.v, d: ddiv(a.d, b.d) };
```
=== in b.v === 0. Usually fine as a guard against dividing by zero; check it is not meant to catch a near-zero value too. Reviewed: Calc sheets, Calc sheet units, functions and driven parameters.
Against 0 match.js:170 in nccPeaks TakeoffCraft
```
if (u > v || (u === v && (dy < 0 || (dy === 0 && dx < 0)))) { best = false; break; }
```
=== in dy === 0. Usually fine as a guard against dividing by zero; check it is not meant to catch a near-zero value too. Reviewed: Automatic count by symbol matching.