nvidia / difix

Difix3D+: Improving 3D Reconstructions with Single-Step Diffusion Models

CVPR 2025 (Oral)
Code | Project Page | Paper

Description:

Difix is a single-step image diffusion model trained to enhance and remove artifacts in rendered novel views caused by underconstrained regions of 3D representation. The technology behind Difix is based on the concepts outlined in the paper titled DIFIX3D+: Improving 3D Reconstructions with Single-Step Diffusion Models .

Difix has two operation modes:

• Offline mode: Used during the reconstruction phase to clean up pseudo-training views that are rendered from the reconstruction and then distill them back into 3D. This greatly enhances underconstrained regions and improves the overall 3D representation quality.
• Online mode: Acts as a neural enhancer during inference, effectively removing residual artifacts arising from imperfect 3D supervision and the limited capacity of current reconstruction models.

Difix is an all-encompassing solution, a single model compatible for both NeRF and 3DGS representations.

This model is ready for research and development/non-commercial use only.

Model Developer: NVIDIA

Model Versions: difix

Deployment Geography: Global

License/Terms of Use:

The use of the model and code is governed by the NVIDIA License. Additional Information: LICENSE.md · stabilityai/sd-turbo at main

Use Case:

Difix is intended for Physical AI developers looking to enhance and improve their Neural Reconstruction pipelines. The model takes an image as an input and outputs a fixed image

Release Date: Github: June 2025

Model Architecture

Architecture Type : UNet

Network Architecture : A latent diffusion-based UNet coupled with a variational autoencoder (VAE).

Input

Input Type(s) : Image

Input Format(s) : Red, Green, Blue (RGB)

Input Parameters : Two-Dimensional (2D)

Other Properties Related to Input :

• Specific Resolution: [576px x 1024px]

Output

Output Type(s) : Image

Output Format(s) : Red, Green, Blue (RGB)

Output Parameters : Two-Dimensional (2D)

Other Properties Related to Output :

• Specific Resolution: [576px x 1024px]

Software Integration

Runtime Engine(s) : PyTorch

Supported Hardware Microarchitecture Compatibility :

• NVIDIA Ampere
• NVIDIA Hopper

Note : We are testing with FP32 Precision.

Inference

Acceleration Engine : PyTorch

Test Hardware :

• A100
• H100

Operating System(s): Linux (We have not tested on other operating systems.)

System Requirements and Performance: This model requires X GB of GPU VRAM. The following table shows inference time for a single generation across different NVIDIA GPU hardware:

Use the Difix Model

Please visit the Difix3D repository to access all relevant files and code needed to use Difix

Difix Dataset

• Data Collection Method: Human
• Labeling Method by Dataset: Human
• Properties: Difix was trained, tested, and evaluated using the DL3DV-10k dataset , where 80% of the data was used for training, 10% for evaluation, and 10% for testing. DL3DV-10K is a large-scale dataset consisting of 10,510 high-resolution (4K) real-world video sequences, totaling approximately 51.2 million frames. The scenes span 65 diverse categories across indoor and outdoor environments. Each video is accompanied by metadata describing environmental conditions such as lighting (natural, artificial, mixed), surface materials (e.g., reflective or transparent), and texture complexity. The dataset is designed to support the development and evaluation of learning-based 3D vision methods.

Ethical Considerations:

NVIDIA believes Trustworthy AI is a shared responsibility and we have established policies and practices to enable development for a wide array of AI applications. When downloaded or used in accordance with our terms of service, developers should work with their internal model team to ensure this model meets requirements for the relevant industry and use case and addresses unforeseen product misuse.

Please report security vulnerabilities or NVIDIA AI Concerns here

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