BabylonJS/Babylon.js · error · Error

Draco: Decoder module is not available

Error message

Draco: Decoder module is not available

What it means

DracoDecoder.decodeMeshToMeshDataAsync throws when `dracoCompression.Configuration.decoder` is not marked available (no decoder module configured/loaded), so there is no DracoDecoderModule instance to decode with. It guards the decode entry point on the main thread before dispatching to workers.

Source

Thrown at packages/dev/core/src/Meshes/Compression/dracoDecoder.ts:220

                        resultIndices = indices;
                    },
                    (kind, data, size, byteOffset, byteStride, normalized) => {
                        resultAttributes.push({
                            kind,
                            data,
                            size,
                            byteOffset,
                            byteStride,
                            normalized,
                        });
                    }
                );

                return { indices: resultIndices!, attributes: resultAttributes, totalVertices: numPoints };
            });
        }

        throw new Error("Draco: Decoder module is not available");
    }

    /**
     * Decode Draco compressed mesh data to Babylon geometry.
     * @param name The name to use when creating the geometry
     * @param scene The scene to use when creating the geometry
     * @param data The ArrayBuffer or ArrayBufferView of the Draco compressed data
     * @param attributes A map of attributes from vertex buffer kinds to Draco unique ids
     * @returns A promise that resolves with the decoded geometry
     */
    public async decodeMeshToGeometryAsync(name: string, scene: Scene, data: ArrayBuffer | ArrayBufferView, attributes?: { [kind: string]: number }): Promise<Geometry> {
        const meshData = await this.decodeMeshToMeshDataAsync(data, attributes);
        const geometry = new Geometry(name, scene);
        if (meshData.indices) {
            geometry.setIndices(meshData.indices);
        }
        for (const attribute of meshData.attributes) {
            geometry.setVerticesBuffer(

View on GitHub (pinned to 0592b347b8)

Solutions

1. Configure the decoder before use: `DracoCompression.Configuration.decoder = { url: "<path>/draco_decoder.js", wasmUrl: ... }` and ensure the URL loads.
2. Preload/await the decoder module (e.g. trigger an init or `whenReadyAsync`) before decoding any Draco data.
3. Check `DracoCompression.Configuration.decoder?.available` before calling decode and load on demand if false.
4. Fallback: skip Draco decode path if the module can't load (decode uncompressed geometry instead).

Example fix

// before
const data = await DracoCompression.DecodeMeshToMeshDataAsync(drcData);

// after
if (!DracoCompression.Configuration.decoder) {
    DracoCompression.Configuration.decoder = { url: "https://cdn.babylonjs.com/draco/draco_decoder.js" };
}
await firstObservedPromise; // ensure decoder module finished loading
const data = await DracoCompression.DecodeMeshToMeshDataAsync(drcData);

if (!DracoCompression.Configuration.decoder || !DracoCompression.Configuration.decoder.available) {
    DracoCompression.Configuration.decoder = { url: "https://cdn.babylonjs.com/draco/draco_decoder.js" };
    await ensureDecoderLoaded();
}

function canDecodeDraco(): boolean {
    return !!DracoCompression.Configuration.decoder?.available;
}

try {
    return await DracoCompression.DecodeMeshToMeshDataAsync(data);
} catch (e) {
    if (e instanceof Error && e.message.includes("Decoder module is not available")) {
        await loadDracoDecoder();
        return await DracoCompression.DecodeMeshToMeshDataAsync(data);
    }
    throw e;
}

When it happens

Trigger: Calling `DracoCompression.DecodeMeshToMeshDataAsync` (or `.decodeMeshToMeshDataAsync`) while `DracoCompression.Configuration.decoder` is undefined/null or its `.available` flag is false.

Common situations: Forgetting to load the Draco decoder script (default CDN unreachable/offline PWA), stripping the decoder config in bundled builds, or an awaited decode running before the configuration object finished loading the WASM.

Related errors

• Draco codec module is not available
• Draco: Decoder module is not available
• Draco: Encoder module is not available
• ${context}: ${error.message}
• Atmosphere is not supported on WebGL ${engine.version}.

AI-assisted analysis of BabylonJS/Babylon.js@0592b347b8 (2026-08-30). Data as JSON: /api/errors/0667f7ca2bf59d60. Report an issue: GitHub.