One chat generated UMG. ""Use llm-material to generate a [xxxxxxx] material based on standard material/substrate.""

Prompt, skill ➡️ https://github.com/ituiyuio/Yomin-Fab-LLM-Unreal-Pluagin-Skill.git

GitPage：LLM Dynamic UI - DSL Schema Guide | YominUnreal Plugins

# LLMMaterial - JSON-driven Material Generation Engine

LLMMaterial is a DSL-driven material generation system for Unreal Engine 5. Create and modify Material Blueprint assets via JSON definitions with full Substrate support.

## Features

- JSON-to-Material: Define materials using `.llmmat` JSON format

- Bidirectional Conversion: Export existing materials back to JSON

- Expression Nodes: Full support for Material Expression nodes (Add, Multiply, TextureSample, etc.)

- Substrate Support: UE5 Substrate BSDF materials (Slab, VerticalLayering, HorizontalMixing)

- HLSL Shader Functions: Define custom `.ush` shader functions inline

- Auto-Layout: Automatic node graph layout with Sugiyama algorithm

- Editor Panel: Three-panel UI (File List, Node Tree, Property Editor)

- Live Preview: Real-time property editing and visual feedback

## Installation

1. Copy `LLMMaterial` plugin to your project's `Plugins/` directory

2. Enable the plugin in Unreal Engine Editor (Edit → Plugins → AI → LLMMaterial)

3. Restart the Editor

## Quick Start

### Create a Material from JSON

```json

{

  "version": "1.0",

  "name": "MyRedMaterial",

  "domain": "Surface",

  "blendMode": "Opaque",

  "shadingModel": "DefaultLit",

  "nodes": [

    {

      "id": "color",

      "type": "Constant3Vector",

      "properties": { "Constant": [1.0, 0.0, 0.0] }

    }

  ],

  "output": {

    "baseColor": { "node": "color", "pin": "Result" }

  }

}

```

Save as `MyMaterial.llmmat` and generate:

```bash

material generate /Game/Materials/MyRedMaterial --from MyMaterial.llmmat

```

### Export Existing Material

```bash

material export /Game/Materials/ExistingMaterial --output export.llmmat

```

## File Format (.llmmat)

```json

{

  "version": "1.0",

  "name": "MaterialName",

  "domain": "Surface",

  "blendMode": "Opaque",

  "shadingModel": "DefaultLit",

  "nodes": [...],

  "connections": [...],

  "output": {...}

}

```

### Material Domains

- `Surface` - Surface material (default)

- `PostProcess` - Post-process material

- `UserInterface` - UI material

- `VirtualTexture` - Virtual texture

### Blend Modes

- `Opaque` - Opaque (default)

- `Masked` - Masked (uses OpacityMask)

- `Translucent` - Translucent

- `Additive` - Additive blending

- `Modulate` - Modulate blending

### Shading Models

- `DefaultLit` - Default lit (default)

- `Unlit` - Unlit

- `Subsurface` - Subsurface scattering

- `SubsurfaceProfile` - Subsurface with profile

- `ClearCoat` - Clear coat

- `Hair` - Hair

- `Cloth` - Cloth

- `Strata` - Strata (for Substrate)

## Node Types

### Math Operations

| Type | Description | Inputs | Outputs |

|------|-------------|--------|---------|

| `Add` | Addition | A, B | Result |

| `Multiply` | Multiplication | A, B | Result |

| `Subtract` | Subtraction | A, B | Result |

| `Divide` | Division | A, B | Result |

| `Power` | Power | Base, Exp | Result |

| `Sine` / `Cosine` | Trigonometry | Input | Result |

| `Clamp` | Clamp range | Input, Min, Max | Result |

| `Lerp` | Linear interpolation | A, B, Alpha | Result |

### Constants

| Type | Description | Properties |

|------|-------------|------------|

| `Constant` | Scalar constant | Value |

| `Constant2Vector` | 2D vector | Constant [X, Y] |

| `Constant3Vector` | 3D vector/color | Constant [R, G, B] |

| `Constant4Vector` | 4D vector/color+Alpha | Constant [R, G, B, A] |

### Textures

| Type | Description | Properties |

|------|-------------|------------|

| `TextureSample` | Texture sample | Texture (path) |

| `TextureCoordinate` | UV coordinates | CoordinateIndex |

### Parameters

| Type | Description | Properties |

|------|-------------|------------|

| `ScalarParameter` | Scalar parameter | ParameterName, DefaultValue |

| `VectorParameter` | Vector parameter | ParameterName, DefaultValue |

| `TextureSampleParameter` | Texture parameter | ParameterName, Texture |

## Substrate Materials

UE5 Substrate provides physically-based layered materials:

```json

{

  "version": "1.0",

  "name": "MySubstrateMaterial",

  "domain": "Surface",

  "substrate": {

    "slabs": [

      {

        "id": "main_slab",

        "type": "SubstrateSlabBSDF",

        "inputs": {

          "DiffuseAlbedo": [0.8, 0.8, 0.8],

          "Roughness": 0.3,

          "F0": [0.04, 0.04, 0.04],

          "Metallic": 0.0

        }

      }

    ],

    "root": { "type": "VerticalLayering", "top": "main_slab" }

  }

}

```

### Slab Types

- `SubstrateSlabBSDF` - Surface BSDF (default)

- `SubstrateHairBSDF` - Hair BSDF

- `SubstrateUnlitBSDF` - Unlit BSDF

- `SubstrateEyeBSDF` - Eye BSDF

- `SubstrateSingleLayerWaterBSDF` - Single layer water

## Editor Panel

The LLMMaterial editor provides a three-panel interface:

1. File List (left): Manage `.llmmat` files

2. Node Tree (center): View material structure

3. Property Panel (right): Edit node properties

### Toolbar Actions

- Generate: Create materials from selected files

- Export Material: Export existing material to JSON

- Export Schema: Export expression schema reference