Physically Compatible 3D Object Modeling from a Single Image

This repository contains the implementation code for the paper Physically Compatible 3D Object Modeling from a Single Image in Neurips 2024 (Spotlight).

We present a computational framework that transforms single images into 3D physical objects. The visual geometry of a physical object in an image is determined by three orthogonal attributes: mechanical properties, external forces, and rest-shape geometry. Existing single-view 3D reconstruction methods often overlook this underlying composition, presuming rigidity or neglecting external forces. Consequently, the reconstructed objects fail to withstand real-world physical forces, resulting in instability or undesirable deformation -- diverging from their intended designs as depicted in the image. Our optimization framework addresses this by embedding physical compatibility into the reconstruction process. We explicitly decompose the three physical attributes and link them through static equilibrium, which serves as a hard constraint, ensuring that the optimized physical shapes exhibit desired physical behaviors.

(Left) The visual geometry of a physical object in an image is determined by three orthogonal attributes: mechanical properties, external forces, and rest-shape geometry. (Right) Given predefined mechanical properties and external forces, our pipeline optimizes the rest-shape geometry to ensure that the shape, when in a state of static equilibrium, aligns with the target image and meets stability criteria.

Installation

Prerequisites

• libpgo: We developed the code using libpgo as the infrastructure. follow the following link to create conda environment and install libpgo.

git clone [email protected]:bohanwang/libpgo.git
cd libpgo
mkdir -p projects
cd projects
git clone [email protected]:gmh14/PhysComp.git
sudo apt install libgmp-dev libmpfr-dev
conda create --name physcomp python=3.10
conda activate physcomp
conda install tbb tbb-devel mkl mkl-devel
export CMAKE_BUILD_PARALLEL_LEVEL=8
cd ..
pip install -v -e .
pip install trimesh tetgen

Usage

Our framework provides two examples to demonstrate its functionality:

1. Soft Object Optimization for Image Matching (matching())
2. Stiff Object Optimization for Stability (stabilize())

The required files for these examples are located in the examples/ directory.

To obtain the results, use the following commands:

cd projects/PhysComp
python scripts/test.py

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Input Files

For both matching() and stabilize():

• reconstruct_res.veg The initial reconstructed 3D model in .veg format.

  • Detailed information on the .veg format can be found here.
  • If you have tetrahedral mesh vertices and elements in NumPy array format, you can convert and save them as .veg using this script.

• fixed.txt A list of vertex indices that are fixed during optimization.

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Output Files

Generated by matching():

• opt_init.veg / opt_init.obj The optimized rest shape geometry of the 3D tetrahedral mesh in .veg format and its surface mesh in .obj format.

• opt.veg / opt.obj The geometry of the optimized rest shape under gravity of the 3D tetrahedral mesh in .veg format and its surface mesh in .obj format.

• static_eq_debug.veg / static_eq_debug.obj The geometry of the unoptimized rest shape under gravity of the 3D tetrahedral mesh in .veg format and its surface mesh in .obj format.

Generated by stabilize():

• stand_opt_rest.veg / stand_opt_rest.obj The optimized rest shape geometry of the 3D tetrahedral mesh in .veg format and its surface mesh in .obj format.

• stand_opt.veg / stand_opt.obj The geometry of the optimized rest shape under gravity of the 3D tetrahedral mesh in .veg format and its surface mesh in .obj format.

Feel free to explore the examples/ directory for additional resources and scripts.

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For stability evaluation, we use rigid-ipc. The configuration JSON file for rigid-ipc is examples/unicorn_rigid_ipc.json. Change the input mesh path to stand_opt_rest_scaled.obj which is scaled to a proper size for visualization.

WIP Features

• Release the data

• More instructions for the usage

Citation

If you find the idea or code useful for your research, please cite our paper:

@article{guo2024physically,
  title={Physically Compatible 3D Object Modeling from a Single Image},
  author={Guo, Minghao and Wang, Bohan and Ma, Pingchuan and Zhang, Tianyuan and Owens, Crystal Elaine and Gan, Chuang and Tenenbaum, Joshua B and He, Kaiming and Matusik, Wojciech},
  journal={Advances in Neural Information Processing Systems},
  year={2024}
}

Contact

Don't hesitate to contact [email protected] if you have any questions. Enjoy!