GaussianSplattingPartProxyMesh: compound mesh not found with

Error message

GaussianSplattingPartProxyMesh: compound mesh not found with ID ${parsedMesh.compoundSplatMeshId}

What it means

When deserializing a GaussianSplattingPartProxyMesh from a serialized scene, Parse resolves its parent compound splat mesh either from an in-memory reference or by ID via scene.getLastMeshById. It throws when neither resolves, meaning the compound mesh is missing from the scene at parse time.

Source

Thrown at packages/dev/core/src/Meshes/GaussianSplatting/gaussianSplattingPartProxyMesh.pure.ts:297

        serializationObject.boundingInfo = {
            minimum: boundingInfo.minimum.asArray(),
            maximum: boundingInfo.maximum.asArray(),
        };
        return serializationObject;
    }

    /**
     * Parses a serialized GaussianSplattingPartProxyMesh
     * @param parsedMesh the serialized mesh
     * @param scene the scene to create the GaussianSplattingPartProxyMesh in
     * @returns the created GaussianSplattingPartProxyMesh
     */
    public static override Parse(parsedMesh: any, scene: Scene): GaussianSplattingPartProxyMesh {
        const partIndex = parsedMesh.partIndex;
        const compoundSplatMesh =
            (parsedMesh.compoundSplatMesh as GaussianSplattingMesh | undefined) ?? (scene.getLastMeshById(parsedMesh.compoundSplatMeshId) as GaussianSplattingMesh | null);
        if (!compoundSplatMesh) {
            throw new Error(`GaussianSplattingPartProxyMesh: compound mesh not found with ID ${parsedMesh.compoundSplatMeshId}`);
        }
        const minimum = Vector3.FromArray(parsedMesh.boundingInfo.minimum);
        const maximum = Vector3.FromArray(parsedMesh.boundingInfo.maximum);
        const boundingInfo = new BoundingInfo(minimum, maximum);
        const vertexCount = parsedMesh.vertexCount ?? 0;
        const splatsDataOffset = parsedMesh.splatsDataOffset ?? 0;
        const shDataOffset = parsedMesh.shDataOffset ?? splatsDataOffset;
        return new GaussianSplattingPartProxyMesh(parsedMesh.name, scene, compoundSplatMesh, partIndex, boundingInfo, vertexCount, splatsDataOffset, shDataOffset);
    }
}

let _Registered = false;
/**
 * Register side effects for gaussianSplattingPartProxyMesh.
 * Safe to call multiple times; only the first call has an effect.
 */
export function RegisterGaussianSplattingPartProxyMesh(): void {
    if (_Registered) {

View on GitHub (pinned to 0592b347b8)

Solutions

Ensure the compound GaussianSplattingMesh is created/registered (added to the scene) before the proxy parts are parsed
Check that parsedMesh.compoundSplatMeshId matches a mesh present in the serialized scene data
Serialize the compound mesh alongside its proxies (or embed the direct compoundSplatMesh reference)

Example fix

// before
// compound mesh never re-created after load
GaussianSplattingPartProxyMesh.Parse(parsedPart, scene);
// after
const compound = GaussianSplattingMesh.Parse(parsedCompound, scene);
GaussianSplattingPartProxyMesh.Parse(parsedPart, scene); // now resolvable

Defensive patterns

Strategy: validation

Validate before calling

const compound = parsedMesh.compoundSplatMesh ?? scene.getLastMeshById(parsedMesh.compoundSplatMeshId);
if (!compound) {
  throw new ReferenceError(`compound mesh ${parsedMesh.compoundSplatMeshId} missing before parsing parts`);
}

Type guard

const compoundExists = (scene: Scene, id?: string, direct?: unknown): direct is GaussianSplattingMesh =>
  !!direct || !!(id && scene.getLastMeshById(id));

Try / catch

try {
  GaussianSplattingPartProxyMesh.Parse(parsedPart, scene);
} catch (e) {
  if (String(e).includes('compound mesh not found')) { await ensureCompoundLoaded(parsedPart.compoundSplatMeshId); retry(); }
  else throw e;
}

Prevention

Serialize compound meshes together with their proxy parts
Recreate the compound mesh before parsing parts on scene load
Validate serialized IDs against scene contents before parsing

When it happens

Trigger: Loading a saved scene where the compound GaussianSplattingMesh was removed, renamed, or not yet (re)created; serializing only the proxy parts without the compound mesh.

Common situations: Partial scene snapshots, manually pruning meshes before .serialize, or loading scenes across versions where compoundSplatMeshId changed.

Related errors

AI-assisted analysis of BabylonJS/Babylon.js@0592b347b8 (2026-08-30). Data as JSON: /api/errors/99224c0bb7261bc6. Report an issue: GitHub.