BabylonJS/Babylon.js · error

Path ${path} is invalid

Error message

Path ${path} is invalid

What it means

Same resolution loop in GLTFPathToObjectConverter.convert(): when a `.length` segment is encountered and the current info level has neither a `length` accessor nor an `__array__` marker, the level is not an array at all, so the loader throws this generic invalid-path error.

Source

Thrown at packages/dev/loaders/src/glTF/2.0/Extensions/gltfPathToObjectConverter.ts:102

            const lastPart = parts[parts.length - 1];
            const split = lastPart.split(".");
            parts.pop();
            parts.push(...split);
        }

        let ignoreObjectTree = false;

        for (const part of parts) {
            const isLength = part === "length";
            if (isLength) {
                // For .length, check if the current level has a 'length' accessor
                if (infoTree.length) {
                    infoTree = infoTree.length;
                } else if (infoTree.__array__) {
                    // Fallback: length of an array that doesn't have explicit length accessor
                    throw new Error(`Path ${path} is invalid - no length accessor`);
                } else {
                    throw new Error(`Path ${path} is invalid`);
                }
                // Set target to the current object tree (the array itself)
                // Only update target if objectTree is defined, otherwise keep the last valid target
                if (objectTree !== undefined) {
                    target = objectTree;
                }
                continue;
            }
            if (infoTree.__ignoreObjectTree__) {
                ignoreObjectTree = true;
            }
            if (infoTree.__array__) {
                infoTree = infoTree.__array__;
            } else {
                infoTree = infoTree[part];
                if (!infoTree) {
                    throw new Error(`Path ${path} is invalid`);
                }

View on GitHub (pinned to 0592b347b8)

Solutions

1. Verify the property before `.length` is actually a glTF array in the object model
2. Remove the `.length` suffix or target a real array root (`/nodes.length`, `/meshes.length`, etc.)
3. Inspect this._infoTree to confirm the segment exists; a missing segment usually indicates a typo
4. Upgrade Babylon.js if the property was added in a newer object model

Example fix

// before
converter.convert("/nodes/0/translation.length"); // translation is a value, not an array root
// after
converter.convert("/nodes.length");

const m = /^(\/[a-zA-Z]+)\.length$/.exec(path);
if (m) {
    const root = m[1].slice(1);
    if (!Array.isArray((gltf as any)[root])) throw new Error(`.length pointer requires an array root: ${path}`);
}

function isLengthPointerOnArray(path: string, gltf: any): boolean {
    if (!path.endsWith(".length")) return false;
    const root = path.slice(1, -".length".length);
    return Array.isArray((gltf as any)[root]);
}

try {
    return converter.convert(path);
} catch (e) {
    if (String(e.message).includes("is invalid")) {
        console.warn(`glTF pointer rejected: ${path}`);
        return null;
    }
    throw e;
}

When it happens

Trigger: Requesting a `.length` pointer (e.g. `/materials.length`) where the segment before `.length` resolves to a scalar/object property in the info tree (not an array and not carrying a length accessor).

Common situations: Typo in a property pointer inside an animation or interactivity graph; applying `.length` to a non-array property like `/materials/0/pbrMetallicRoughness/baseColorFactor.length`; asset authored against an object-model version that lacks the property.

Related errors

• Path ${path} is invalid - no length accessor
• BabylonScenePathToObjectConverter: path "${path}" does not s
• BabylonScenePathToObjectConverter: path "${path}" is missing
• BabylonScenePathToObjectConverter: unknown collection "${col
• BabylonScenePathToObjectConverter: path "${path}" is missing

AI-assisted analysis of BabylonJS/Babylon.js@0592b347b8 (2026-08-30). Data as JSON: /api/errors/8c837701f9c9dacc. Report an issue: GitHub.