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ShapeFlow

[NeurIPS 20'] ShapeFlow: Learnable Deformations Among 3D Shapes.

By: Chiyu "Max" Jiang*, Jingwei Huang*, Andrea Tagliasacchi, Leonidas Guibas

[Project Website] [Paper]

1. Introduction

We present ShapeFlow, a flow-based model for learning a deformation space for entire classes of 3D shapes with large intra-class variations. ShapeFlow allows learning a multi-template deformation space that is agnostic to shape topology, yet preserves fine geometric details. Different from a generative space where a latent vector is directly decoded into a shape, a deformation space decodes a vector into a continuous flow that can advect a source shape towards a target. Such a space naturally allows the disentanglement of geometric style (coming from the source) and structural pose (conforming to the target). We parametrize the deformation between geometries as a learned continuous flow field via a neural network and show that such deformations can be guaranteed to have desirable properties, such as bijectivity, freedom from self-intersections, or volume preservation. We illustrate the effectiveness of this learned deformation space for various downstream applications, including shape generation via deformation, geometric style transfer, unsupervised learning of a consistent parameterization for entire classes of shapes, and shape interpolation.

2. Getting Started

Installing dependencies

We recommend using pip to install all required dependencies with ease.

pip install -r requirements.txt

Optional dependency (rendering)

We strongly suggest installing the optional dependencies for rendering meshes, so that you can visualize the results using interactive notebooks. pyrender can be installed via pip:

pip install pyrender

Additionally to run the notebook renderings on a headless server, follow the instructions for installing OSMesa.

Download and unpack data

To download and unpack the data used in the experiment, please use the utility script privided.

bash download_data.sh

3. Reproduce results

Run experiments

Please use our provided launch script to start training the shape deformation model.

bash shapenet_train.sh

The training will launch on all available GPUs. Mask GPUs accordingly if you want to use only a subset of all GPUs. The initial tests are done on NVIDIA Volta V100 GPUs, therefore the batch_size_per_gpu=16 might need to be adjusted accordingly for GPUs with smaller or larger memory limits if the out of memory error is triggered.

Load and visualize pretrained checkpoint

First download the pretrained checkpoint.

wget island.me.berkeley.edu/files/pretrained_ckpt.zip
mkdir -p runs
mv pretrained_ckpt.zip runs
cd runs; unzip pretrained_ckpt.zip; rm pretrained_ckpt.zip; cd ..

Next, run through the cells in visualize_deformer.ipynb.

Monitor training

After launching the training script, a runs directory will be created, with different runs each as a separate subfolder within. To monitor the training process based on text logs, use

tail -f runs/<job_name>/log.txt

To monitor the training process using tensorboard, do:

# if you are running this on a remote server via ssh
ssh my_favorite_machine -L 6006:localhost:6006

# go to the directory containing the tensorboard log
cd path/to/ShapeFlow/runs/<job_name>/tensorboard

# launch tensorboard
tensorboard --logdir . --port 6006

Tensorboard allows tracking of deformation losses, as well as visualizing the source / target / deformed meshes. The deformed meshes are colored by the distance per vertex with respect to target shape.

Citation

If you find our code useful for your work, please consider citing our paper:

@inproceedings{jiang2020shapeflow,
  title={ShapeFlow: Learnable Deformations Among 3D Shapes},
  author={Jiang, Chiyu and Huang, Jingwei and Tagliasacchi, Andrea and Guibas, Leonidas},
  booktitle={Advances in Neural Information Processing Systems},
  year={2020}
}

Contact

Please contact Max Jiang if you have further questions!