🎯 One chat generated MetaSound.

"Use llm-metasound to generate a [laser / explosion / footstep / ambient] sound for [your SFX]."

📚 Tutorial: LLM MetaSound - DSL Schema Guide · 🛠 Skill Repo: github.com/ituiyuio/Yomin-Fab-LLM-Unreal-Pluagin-Skill

Features:

✅ One JSON, Complete Audio Graph - Inputs, outputs, nodes, and edges generated from a single .llmmetasound file

✅ LLM-First Design - AI outputs JSON directly, no MetaSound editor knowledge required

✅ Bidirectional Conversion - JSON ↔ UMetaSoundSource / UMetaSoundPatch, perfect roundtrip

✅ Robust Edge Handling - UE5 Builder Subsystem + auto-connect OnPlay + vertex type validation on every wire

✅ Full Node Coverage - MetasoundFrontend registry with autocomplete + graph-level Inputs / Outputs

✅ Two Asset Types - UMetaSoundSource (transport + audio playback) and UMetaSoundPatch (pure DSP)

✅ Editor Panel - Slate-based panel for one-click generation and re-export

✅ Type-Safe Pin Wiring - Edges that mismatch vertex types are rejected before the asset is saved

📦 File Formats:

.llmmetasound (JSON), .llmmetasoundschema (Schema), UMetaSoundSource / UMetaSoundPatch (UAsset)

Technical Information

Version: Unreal Engine 5.7+

Dependencies: Metasound (engine plugin, enabled by default in UE5)

Modules: LLMMetaSoundEditor (Editor)

Number of Blueprints: 0

Number of C++ Classes: ~12

Network Replicated: No

Documentation Link: LLM MetaSound DSL Schema Guide

Example Project: Config/Examples/ folder contains .llmmetasound example files

Supported Platforms: Windows, Mac, Linux

Overview

The Problem

Traditional UE MetaSound development is tedious:

• Navigate the node browser manually for every operator

• Set properties one by one in the details panel

• Connect pins by hand with no type validation

• No AI integration for generative or batch-authored audio

• Hard to version control audio graphs

The Solution

LLMMetaSound changes everything. One JSON file defines:

• Asset type (Source or Patch)

• Graph interface members (Inputs and Outputs)

• All nodes with their class names and locations

• All edges connecting node pins (type-safe)

LLM outputs the JSON. Plugin generates the MetaSound asset. Done.

Example

{ "Metadata": { "NodeName": "SimpleSynth", "NodeType": "MetasoundSource", "MetasoundDescription": "Sine oscillator with gain and frequency inputs" }, "Inputs": [ { "Name": "Frequency", "TypeName": "Primitive:Float", "LiteralValue": { "LiteralType": "Float", "AsFloat": 440.0 } }, { "Name": "Gain", "TypeName": "Primitive:Float", "LiteralValue": { "LiteralType": "Float", "AsFloat": 1.0 } } ], "Nodes": [ { "NodeID": 1, "ClassName": "Input", "Name": "Frequency", "TypeName": "Primitive:Float" }, { "NodeID": 2, "ClassName": "Input", "Name": "Gain", "TypeName": "Primitive:Float" }, { "NodeID": 3, "ClassName": "Sine", "Name": "Osc" }, { "NodeID": 4, "ClassName": "Multiply", "ClassPath": "UE.Multiply.AudiobyFloat", "Name": "GainMul" }, { "NodeID": 5, "ClassName": "Envelope Follower", "Name": "AmpEnv", "InputDefaults": { "Enable": { "LiteralType": "Boolean", "AsBool": true } } } ], "Edges": [ { "FromNodeID": 1, "FromPinName": "Frequency","ToNodeID": 3, "ToPinName": "Frequency" }, { "FromNodeID": 3, "FromPinName": "Audio","ToNodeID": 4, "ToPinName": "PrimaryOperand" }, { "FromNodeID": 2, "FromPinName": "Gain","ToNodeID": 4, "ToPinName": "AdditionalOperands" }, { "FromNodeID": 4, "FromPinName": "Out","ToNodeID": 5, "ToPinName": "In" } ] }

Import this JSON → Get a fully functional MetaSound asset with auto-connected nodes. The OnPlay trigger and final audio output are wired automatically — you only describe the graph nodes and edges (no manual ClassName: "Output" node needed; the plugin auto-routes audio to the engine's audio output pin).

Workflow

1. LLM generates .llmmetasound - AI outputs JSON with your audio graph definition

2. Open Panel - Window → LLMMetaSound

3. Generate - One click creates the MetaSound asset

4. Iterate - Modify JSON, regenerate, or export existing MetaSound back to JSON

Supported MetaSound Types

TypeDescriptionUMetaSoundSourceAudio playback graph with transport (auto-connected OnPlay trigger)UMetaSoundPatchPure DSP patch without transport

Supported Node Classes

Oscillator · Output · Delay · Gain · Envelope · Filter · LFO · Mixer · Split · Merge · MonoToStereo · StereoToMono · and all MetasoundStandardNodes discovered from the engine registry.

Schema Quick Reference

FieldDescriptionAssetType"Source" or "Patch"Metadata.NodeNameAsset display nameInputs[]Graph-level input interface membersOutputs[]Graph-level output interface membersNodes[]Graph nodes (external nodes, not Input/Output nodes)Edges[]Connections between node pins (type-validated)Node.NodeIDInteger ID referenced by edgesNode.ClassNameMetaSound node class (e.g., "Oscillator")

Successful development to you!

LLMMetaSound v1.0.0 | YominUnreal