---
license: apache-2.0
tags:
  - defect-generation
  - anomaly-detection
  - industrial-inspection
  - lora
  - flux
  - diffusion
  - rlhf
language: en
pipeline_tag: image-to-image
---

# UniDG-RFT-LoRA

LoRA weights for **UniDG** (Universal Defect Generation), trained via **Consistency-RFT** with Flow-GRPO and dual reward models on the UDG dataset (300K quadruplets).

[[Paper]](https://arxiv.org/abs/2604.08915) [[Code]](https://github.com/RetoFan233/UniDG) [[UniDG-SFT-LoRA]](https://huggingface.co/retofan23333/UniDG-SFT-LoRA-Release)

## Overview

UniDG is a universal defect generation foundation model that transfers defects from a reference image to a target region via **Defect-Context Editing** and **MM-DiT multimodal attention**, without per-category fine-tuning. This checkpoint is the **Consistency-RFT** variant, further refined from UniDG-SFT using Flow-GRPO with dual reward models (Defect-Und-Reward & Defect-Recog-Reward) for improved defect fidelity and consistency.

| Variant | Training | Focus |
|---------|----------|-------|
| UniDG-SFT | Diversity-SFT with complementary sampling | Diverse defect patterns |
| **UniDG-RFT** (this) | Consistency-RFT with Flow-GRPO + dual rewards | Consistent & faithful defects |

## Important: Usage Difference from UniDG-SFT-LoRA

**The UniDG-RFT-LoRA weights are stored in PEFT format** (`adapter_model.safetensors` + `adapter_config.json`), which is different from UniDG-SFT-LoRA (which uses `pytorch_lora_weights.safetensors`). This means:

- **UniDG-SFT-LoRA** can be directly loaded via the `lora_weights_path` parameter in `ImageUniDG`.
- **UniDG-RFT-LoRA** must first be **merged into the base SFT model** using the provided `combine_peft_weights.py` script. After merging, the resulting model can be loaded directly without any additional LoRA loading step.

## Repository Contents

| File | Description |
|------|-------------|
| `adapter_model.safetensors` | PEFT LoRA weights (Consistency-RFT) |
| `adapter_config.json` | LoRA configuration (rank=64, alpha=128) |
| `combine_peft_weights.py` | Script to merge RFT LoRA into the base SFT model |

## Step-by-Step Usage

### Prerequisites

- [FLUX.1-Fill-dev](https://huggingface.co/black-forest-labs/FLUX.1-Fill-dev) (inpainting backbone)
- [FLUX.1-Redux-dev](https://huggingface.co/black-forest-labs/FLUX.1-Redux-dev) (reference conditioning)
- [UniDG-SFT-LoRA](https://huggingface.co/retofan23333/UniDG-SFT-LoRA-Release) (base SFT model — the RFT LoRA is fine-tuned on top of this)
- [UniDG code](https://github.com/RetoFan233/UniDG) (inference framework)
- Python dependencies: `diffusers`, `peft`, `torch`

### Step 1: Prepare the Base SFT Model

First, you need a base FLUX.1-Fill-dev model with UniDG-SFT-LoRA weights already merged in. If you haven't done this, you can prepare it by loading the SFT model and saving the merged weights:

```python
from diffusers import FluxFillPipeline
import torch

# Load base FLUX.1-Fill-dev
pipe = FluxFillPipeline.from_pretrained(
    "path/to/FLUX.1-Fill-dev",
    torch_dtype=torch.bfloat16,
)

# Load SFT LoRA weights
pipe.load_lora_weights("path/to/UniDG-SFT-LoRA-Release/pytorch_lora_weights.safetensors")

# Save the merged SFT model as the base for RFT merging
pipe.save_pretrained("path/to/FLUX.1-Fill-dev-UDG-SFT", safe_serialization=True, max_shard_size="5GB")
```

### Step 2: Merge RFT LoRA into the Base SFT Model

Use the provided `combine_peft_weights.py` to merge the RFT LoRA weights into the base SFT model:

```bash
python combine_peft_weights.py \
    --base_model_path path/to/FLUX.1-Fill-dev-UDG-SFT \
    --lora_weights_path path/to/UniDG-RFT-LoRA-Release \
    --output_path path/to/FLUX.1-Fill-dev-UDG-RFT \
    --save_full_pipeline
```

Parameters:
- `--base_model_path`: Path to the base SFT model (from Step 1)
- `--lora_weights_path`: Path to this RFT LoRA repository (containing `adapter_model.safetensors` and `adapter_config.json`)
- `--output_path`: Output path for the merged model
- `--save_full_pipeline`: Save the full pipeline (including VAE, text encoder, etc.) so you can load it directly later
- `--dtype`: Data type, default `bfloat16`
- `--device`: Device for loading, default `cpu` (recommended to avoid OOM)

> **Tip**: Use `--device cpu` (default) to save GPU memory during the merge process. The merge only needs to run once.

### Step 3: Use the Merged Model with UniDG

After merging, the model can be used directly with the UniDG inference code — **no additional LoRA loading is needed**:

```python
from unidg import ImageUniDG
from PIL import Image
import torch

# Load the merged RFT model — set lora_weights_path="" since LoRA is already merged
model = ImageUniDG(
    flux_model_path="path/to/FLUX.1-Fill-dev-UDG-RFT",
    redux_model_path="path/to/FLUX.1-Redux-dev",
    lora_weights_path="",  # No additional LoRA needed!
    device="cuda:0",
    dtype=torch.bfloat16,
)

result, mask = model.process_images(
    target_image=Image.open("target.jpg"),
    reference_image=Image.open("reference.jpg"),
    reference_mask=Image.open("reference_mask.png"),
    target_mask=Image.open("target_mask.png"),
    num_inference_steps=28,
    guidance_scale=3.5,
    seed=42,
)
result.save("result.png")
```

### Quick Reference: SFT vs RFT Usage

| | UniDG-SFT | UniDG-RFT |
|---|-----------|-----------|
| Weight format | `pytorch_lora_weights.safetensors` | `adapter_model.safetensors` + `adapter_config.json` |
| Merge required? | No | Yes (with SFT base model) |
| `lora_weights_path` | Path to SFT weights | `""` (empty, after merge) |
| `flux_model_path` | `path/to/FLUX.1-Fill-dev` | `path/to/merged-RFT-model` |
| Load time | LoRA loaded on-the-fly | Pre-merged, no LoRA overhead |

## LoRA Configuration

| Parameter | Value |
|-----------|-------|
| PEFT type | LORA |
| Rank (r) | 64 |
| Alpha | 128 |
| Dropout | 0.0 |
| Target modules | `ff.net.0.proj`, `ff.net.2`, `ff_context.net.0.proj`, `proj_mlp`, `attn.to_q`, `attn.to_v`, `attn.to_add_out`, `attn.add_k_proj`, `attn.add_v_proj`, `ff_context.net.2`, `attn.add_q_proj`, `attn.to_out.0`, `attn.to_k` |
| Base model | FLUX.1-Fill-dev + UniDG-SFT-LoRA |

## Citation

```bibtex
@article{fan2026unidg,
  title={Large-Scale Universal Defect Generation: Foundation Models and Datasets},
  author={Fan, Yuanting and Liu, Jun and Gao, Bin-Bin and Chen, Xiaochen and Lin, Yuhuan and Dai, Zhewei and Zhan, Jiawei and Wang, Chengjie},
  journal={arXiv preprint arXiv:2604.08915},
  year={2026}
}
```