BabylonJS/Babylon.js · critical · Error

Missing arrays in SOG scales data.

Error message

Missing arrays in SOG scales data.

What it means

In SOG version 1 (non-codebook) files, scales are dequantized per-component via linear interpolation between per-axis mins and maxs arrays stored in meta.json. This error means data.scales.mins or data.scales.maxs is missing or is not an array (SOGDataFile types them as number | number[]; a scalar is only valid for shN), so scale values cannot be reconstructed from the 8-bit image data.

Source

Thrown at packages/dev/loaders/src/SPLAT/sog.pure.ts:199

    }

    // --- Scales
    const scales = imageDataArrays[2].bits;
    if (data.version === 2) {
        if (!data.scales.codebook) {
            throw new Error("Missing codebook in SOG version 2 scales data.");
        }
        for (let i = 0; i < splatCount; i++) {
            const index = i * 4;
            for (let j = 0; j < 3; j++) {
                const sc = data.scales.codebook[scales[index + j]];
                const sce = Math.exp(sc);
                scale[i * 8 + 3 + j] = sce;
            }
        }
    } else {
        if (!Array.isArray(data.scales.mins) || !Array.isArray(data.scales.maxs)) {
            throw new Error("Missing arrays in SOG scales data.");
        }

        for (let i = 0; i < splatCount; i++) {
            const index = i * 4;
            for (let j = 0; j < 3; j++) {
                const sc = scales[index + j];
                const lsc = Scalar.Lerp(data.scales.mins[j], data.scales.maxs[j], sc / 255);
                const lsce = Math.exp(lsc);
                scale[i * 8 + 3 + j] = lsce;
            }
        }
    }

    // --- Colors/SH0
    const colors = imageDataArrays[4].bits;
    if (data.version === 2) {
        if (!data.sh0.codebook) {
            throw new Error("Missing codebook in SOG version 2 sh0 data.");

View on GitHub (pinned to 0592b347b8)

Solutions

  1. Add the correct 3-element mins/maxs arrays to the scales entry of meta.json (matching what the encoder used for quantization).
  2. If the asset is v2, restore version: 2 in meta.json so the codebook path is used and mins/maxs are not required.
  3. Pre-validate meta.json: Array.isArray(meta.scales.mins) && Array.isArray(meta.scales.maxs) when version !== 2.

Example fix

// before
"scales": { "shape": [100000, 3], "dtype": "uint8", "files": ["scales.webp"] }
// after
"scales": { "shape": [100000, 3], "dtype": "uint8", "files": ["scales.webp"], "mins": [-4.2, -4.2, -4.2], "maxs": [4.2, 4.2, 4.2] }
Defensive patterns

Strategy: validation

Validate before calling

function validateV1Scales(meta) {
  if (meta.version !== 2 &&
      !(Array.isArray(meta.scales?.mins) && meta.scales.mins.length === 3 &&
        Array.isArray(meta.scales?.maxs) && meta.scales.maxs.length === 3)) {
    throw new Error('v1 SOG asset: meta.scales.mins/maxs (3-element arrays) are required');
  }
}

Type guard

function hasScalesRanges(meta) {
  return Array.isArray(meta.scales?.mins) && Array.isArray(meta.scales?.maxs) &&
         meta.scales.mins.length === 3 && meta.scales.maxs.length === 3;
}

Try / catch

try {
  return await ParseSogMeta(metaOrFiles, rootUrl, scene);
} catch (e) {
  if (e.message === 'Missing arrays in SOG scales data.') {
    // meta.scales lacks mins/maxs: asset is malformed for its declared version
  }
  throw e;
}

Prevention

When it happens

Trigger: Parsing a SOG bundle (ParseSogMeta) whose meta.json omits mins/maxs on the scales entry, or supplies them as a scalar instead of a 3-element array; also fires when a v2-encoded file has its version field missing/reset so the code falls into the v1 branch.

Common situations: Hand-written or trimmed meta.json from an external SOG tool; an encoder bug that emits scalar mins/maxs for scales; version field stripped by a minifier/JSON transform causing v2 data to take the v1 code path.

Related errors

AI-assisted analysis of BabylonJS/Babylon.js@0592b347b8 (2026-08-30). Data as JSON: /api/errors/4dd4d731e57bd816. Report an issue: GitHub.