Code for Neural Reflectance Surfaces (NeRS)

[arXiv] [Project Page] [Colab Demo] [MVMC Data] [Bibtex]

This repo contains the code for NeRS: Neural Reflectance Surfaces.

The code was tested with the following dependencies:

• Python 3.8.6
• Pytorch 1.7.0
• Pytorch3d 0.5.0
• CUDA 11.0

Installation

Setup

We recommend using conda to manage dependencies. Make sure to install a cudatoolkit compatible with your GPU.

git clone git@github.com:jasonyzhang/ners.git
conda create -n ners python=3.8
conda activate ners
conda install -c pytorch pytorch=1.7.1 torchvision cudatoolkit=10.2
pip install -r requirements.txt

Installing Pytorch3d

Here, we list the recommended steps for installing Pytorch3d. Refer to the official installation directions for troubleshooting and additional details.

mkdir -p external
git clone --depth 1 --branch v0.5.0 https://github.com/facebookresearch/pytorch3d.git external/pytorch3d
cd external/pytorch3d
conda activate ners
conda install -c conda-forge -c fvcore -c iopath -c bottler fvcore iopath nvidiacub
python setup.py install

If you need to compile for multiple architectures (e.g. Turing for 2080TI and Maxwell for 1080TI), you can pass the architectures as an environment variable, i.e. TORCH_CUDA_ARCH_LIST="Maxwell;Pascal;Turing;Volta" python setup.py install.

If you get a warning about the default C/C++ compiler on your machine, you should compile Pytorch3D using the same compiler that your pytorch installation uses, likely gcc/g++. Try: CC=gcc CXX=g++ python setup.py install.

Acquiring Object Masks

To get object masks, we recommend using PointRend for COCO classes or GrabCut for other categories.

If using GrabCut, you can try this interactive segmentation tool.

Running the Code

Running on MVMC

Use the --mvmc flag to use the MVMC dataloader. A sample car is included in the repo.

python main.py --instance-dir data/mvmc/7246694387 --mvmc --export-mesh --symmetrize

To download the MVMC dataset (576 instances), run the following command:

gdown https://drive.google.com/uc?id=1P7BhDyUPhf4IF2FOWwddztYvjtIxR3II
unzip -n mvmc.zip -d data

To run on the entire MVMC dataset, run the following (note that this will take a long time, roughly 10 days to run on a single 4-GPU machine. It is recommended to parallelize using --index and --start):

python scripts/mvmc_driver.py

Running on Your Own Objects

We recommend beginning with the demo notebook so that you can visualize the intermediate outputs. The demo notebook generates the 3D reconstruction and illumination prediction for the espresso machine (data included). You can also run the demo script:

python main.py --instance-dir data/espresso --symmetrize --export-mesh --predict-illumination

We also provide a Colab notebook that runs on a single GPU. Note that the Colab demo does not include the view-dependent illumination prediction. At the end of the demo, you can view the turntable NeRS rendering and download the generated mesh as an obj.

To run on your own objects, you will need to acquire images and masks. See data/espresso for an example of the expected directory structure.

We also provide the images and masks for all objects in the paper. All objects except hydrant and robot should have a --symmetrize flag.

gdown https://drive.google.com/uc?id=1JWuofTIlcLJmmzYtZYM2SvZVizJCcOU_
unzip -n misc_objects.zip -d data

Initializing with Non-cuboid Mesh

If your object cannot be initialized from a cuboid shape, or if you wish to use a specific mesh as the initial template, you can also initialize f_template with a specific mesh model.

First, you will need a mapping from the mesh vertices to spherical coordinates. We recommend using this repo to learn this mapping. The initial mesh should be water-tight and genus-0. It may be helpful to decimate the mesh to make it simpler.

Once you have an object mesh and the corresponding sphere mesh, use the pre-processing script to initialize the f_template network:

python -m scripts.pretrain_shape_template \
    --object-mesh models/meshes/car.obj \
    --sphere-mesh models/meshes/car_sphere.obj \
    --output-path models/templates/car.pth

Evaluation

Please see eval.md for evaluation instructions.

Citing NeRS

If you use find this code helpful, please consider citing:

@inproceedings{zhang2021ners,
  title={{NeRS}: Neural Reflectance Surfaces for Sparse-view 3D Reconstruction in the Wild},
  author={Zhang, Jason Y. and Yang, Gengshan and Tulsiani, Shubham and Ramanan, Deva},
  booktitle={Conference on Neural Information Processing Systems},
  year={2021}
}