SMPL layer for PyTorch

SMPL human body [1] layer for PyTorch (tested with v0.4 and v1.x) is a differentiable PyTorch layer that deterministically maps from pose and shape parameters to human body joints and vertices. It can be integrated into any architecture as a differentiable layer to predict body meshes. The code is adapted from the manopth repository by Yana Hasson.

Setup

1. The smplpytorch package

• Run without installing: You will need to install the dependencies listed in environment.yml:
  • conda env update -f environment.yml in an existing environment, or
  • conda env create -f environment.yml, for a new smplpytorch environment
• Install: To import SMPL_Layer in another project with from smplpytorch.pytorch.smpl_layer import SMPL_Layer do one of the following.
  • Option 1: This should automatically install the dependencies.

    git clone https://github.com/gulvarol/smplpytorch.git
    cd smplpytorch
    pip install .
    

  • Option 2: You can install smplpytorch from PyPI. Additionally, you might need to install chumpy.

    pip install smplpytorch
    

2. Download SMPL pickle files

• Download the models from the SMPL website by choosing "SMPL for Python users". Note that you need to comply with the SMPL model license.
• Extract and copy the models folder into the smplpytorch/native/ folder (or set the model_root parameter accordingly).

Demo

Forward pass the randomly created pose and shape parameters from the SMPL layer and display the human body mesh and joints:

python demo.py

Acknowledgements

The code largely builds on the manopth repository from Yana Hasson, which implements the MANO hand model [2] layer.

The code is a PyTorch port of the original SMPL model from chumpy. It builds on the work of Loper et al. [1].

The code reuses part of the code by Zhang Xiong to compute the rotation utilities.

If you find this code useful for your research, please cite the original SMPL publication:

@article{SMPL:2015,
    author = {Loper, Matthew and Mahmood, Naureen and Romero, Javier and Pons-Moll, Gerard and Black, Michael J.},
    title = {{SMPL}: A Skinned Multi-Person Linear Model},
    journal = {ACM Trans. Graphics (Proc. SIGGRAPH Asia)},
    number = {6},
    pages = {248:1--248:16},
    volume = {34},
    year = {2015}
}

References

[1] Matthew Loper, Naureen Mahmood, Javier Romero, Gerard Pons-Moll, and Michael J. Black, "SMPL: A Skinned Multi-Person Linear Model," SIGGRAPH Asia, 2015.

[2] Javier Romero, Dimitrios Tzionas, and Michael J. Black, "Embodied Hands: Modeling and Capturing Hands and Bodies Together," SIGGRAPH Asia, 2017.