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NeuPhysics: Editable Neural Geometry and Physics from Monocular Videos

Yi-Ling Qiao*, Alexander Gao*, Ming C. Lin

Paper | Project Page | Video

We present a method for learning 3D geometry and physics parameters of a dynamic scene from only a monocular RGB video input.

Setup

This code has been tested on Ubuntu 20.04 with CUDA 11.3

Clone this repository and install dependencies. (Recommended to create a new conda env or pipenv.)

git clone https://github.com/gaoalexander/neuphysics.git
cd neuphysics
pip install -r requirements.txt

Data

Download data and pretrained model weights on Google Drive.

Extract public_data and exp directories into the top-level neuphysics directory.

Data Convention

The data is organized as follows:

<case_name>
|-- cameras_xxx.npz    # camera parameters
|-- sparse_points_interest.ply    # contains scene ROI
|-- image
    |-- 000.png        # target image for each view
    |-- 001.png
    ...
|-- mask
    |-- 000.png        # target mask each view (For unmasked setting, set all pixels as 255)
    |-- 001.png
    ...

Here the cameras_xxx.npz follows the data format in IDR, where world_mat_xx denotes the world to image projection matrix, and scale_mat_xx denotes the normalization matrix.

Running

• Training without mask

python run.py --mode train --conf ./confs/neuphysics_default.conf --case <case_name>

• Extract surface from trained model for single frame/timestep

python run.py --mode validate_mesh --val_frame_idx <frame_index> --conf <config_file> --case <case_name> --is_continue # use latest checkpoint

• Extract surface from trained model for entire motion sequence

python run.py --mode validate_mesh_sequence --conf <config_file> --case <case_name> --is_continue # use latest checkpoint

The corresponding mesh can be found in exp/<case_name>/<exp_name>/meshes/<iter_steps>.ply.

• View interpolation

python run.py --mode interpolate_<img_idx_0>_<img_idx_1> --conf <config_file> --case <case_name> --is_continue # use latest checkpoint

The corresponding image set of view interpolation can be found in exp/<case_name>/<exp_name>/render/.

• Train physics parameters Download the pretrained model weights on this Google Drive.

Install warp for differentiable simulation.

Run

python run.py --conf ./confs/womask.conf --case NeuS/custom/ball-motion3/preprocessed --mode train_physics_gravity_warp --is_continue

We are using warp because it runs on GPU and is much faster. We are also trying to provide the interface to taichi.

Train NeuPhysics with your own data

More information can be found in preprocess_custom_data.

Citation

If you find this repository helpful, please consider citing our paper as well as others that our work built upon:

@inproceedings{qiao2022neuphysics,
    author  = {Qiao, Yi-Ling and Gao, Alexander and Lin, Ming C.},
    title  = {NeuPhysics: Editable Neural Geometry and Physics from Monocular Videos},
    booktitle = {Conference on Neural Information Processing Systems (NeurIPS)},
    year  = {2022},
}

@article{wang2021neus,
      title={NeuS: Learning Neural Implicit Surfaces by Volume Rendering for Multi-view Reconstruction}, 
      author={Peng Wang and Lingjie Liu and Yuan Liu and Christian Theobalt and Taku Komura and Wenping Wang},
    journal={NeurIPS},
      year={2021}
}

@inproceedings{tretschk2021nonrigid,
    title = {Non-Rigid Neural Radiance Fields: Reconstruction and Novel View Synthesis of a Dynamic Scene From Monocular Video},
    author = {Tretschk, Edgar and Tewari, Ayush and Golyanik, Vladislav and Zollh\"{o}fer, Michael and Lassner, Christoph and Theobalt, Christian},
    booktitle = {{IEEE} International Conference on Computer Vision ({ICCV})},
    year = {2021},
}

@article{du2021_diffpd,
    author = {Du, Tao and Wu, Kui and Ma, Pingchuan and Wah, Sebastien and Spielberg, Andrew and Rus, Daniela and Matusik, Wojciech},
    title = {DiffPD: Differentiable Projective Dynamics},
    year = {2021},
    journal = {ACM Trans. Graph.},
}
         

Acknowledgement

Our code borrows from NeuS and NonRigid NeRF. Additionally, some code snippets are borrowed from IDR and NeRF-pytorch.

Thank you to the authors of these projects for their great work.