Predicting the Physical Dynamics of Unseen 3D Objects

WACV 2020

Davis Rempe, Srinath Sridhar, He Wang, Leonidas J. Guibas

This repository contains the code and dataset used in the paper "Predicting the Physical Dynamics of Unseen 3D Objects" presented at WACV 2020. See the project page for more details.

Setup

This code has been tested on Ubuntu 16.04 using Python 2.7 and Tensorflow 1.13.1 with CUDA 10.0. After installing CUDA, all dependencies can be installed from the root of this repo with:

pip install -r requirements.txt

Downloads

In order to run the code, you must download and place a few things in the repo:

• All simulated data can be downloaded by running wget http://download.cs.stanford.edu/orion/predicting_physical_dynamics/SimData.zip (1 GB). After unzipping, all data directories should be placed in data/sim/. For more information on data see the readme.
• Pre-trained PointNet weights that we use to initialize training can be downloaded by running wget http://download.cs.stanford.edu/orion/predicting_physical_dynamics/pretrained_pointnet.zip (43 MB) and should be placed in the pretrained directory.
• If you want to visualize results, you will need to download the shape meshes by running wget http://download.cs.stanford.edu/orion/predicting_physical_dynamics/VizShapes.zip (20 MB). They should be placed in viz_unity/DataIn.

Structure

The important parts of this repository are as follows:

• data is where simulated data for training/testing should be placed. Additionally, it already contains all configuration files needed to properly load and use the dataset. Please see the data readme for more information.
• scripts contains all code pertaining to our method including training and testing scripts and models. See below for instructions to run these scripts.
• viz_unity contains a Unity3D project that can be used to visualize results. See below for instructions to use this project.

Running

Below are directions to train, test, and visualize results from our method.

Training and Testing

To train our model, use a command similar to:

python scripts/train/topple_aa_train_classify.py @./data/configs/Cube5k.train.cfg

where all flags for training are passed in via the given configuration file after @. To see the possible options for training and understand the configuration file please see the data readme. The command for training our model on any datset is more or less the same, the only differences being the --data_list and --norm_info flags which are configured differently for each dataset.

To test the trained model, use the command:

python scripts/test/topple_aa_test_classify.py @./data/configs/Cube5k.test.cfg

Similar to the train command, all flags are contained in the configuration file. Different evaluations are performed based on the given flags; see the data readme for full details.

If running into issues with pickle, you may need to regenerate some preprocessing done on the data (used to normalize for training/evaluation). For example for the cube data run:

python scripts/data/calc_normalization_info.py --data_list ./data/sim/dataset_lists/Cube5k/all.txt --info_out ./data/sim/normalization_info/cube_5k.pkl

Visualization

For visualizing predicted trajectories, we use the Unity game engine. We have tested our Unity project on version 2017.3.1f1 on Windows 10, but it is a small project and should work in other versions. The visualization is meant to be run on output predictions from the test script using the --output_pred flag. To visualize results, place the required meshes mentioned earlier in viz_unity/DataIn.

After installing Unity, open the project (with base directory at viz_unity/VizPredictions) and in the editor double-click to open Scenes/TumbleVizPred. To run the visualization script:

• Click the PredictionVisualizer object in the Hierarchy panel to view all options for visualization in the Inspector panel.
• Make sure that Pred Data Dirs has at least one element which points to the output directory of the test script (i.e., pred_out). Increase the size and add more paths if visualizing outputs from multiple directories.
• Make sure Mesh Sources has at least one element and points to the directory containing the meshes to use for visualization (i.e., Cubes/CubeAll. If visualizing results for the combined dataset, every object category should be added as a mesh source.
• Set Data Out Dir path which is where the rendered frames of each prediction will be saved.
• Change any other desired options; the tooltips explain what each option does.
• Make sure BUILD_MODE is not checked if running within the Unity Editor.
• Click the play button.

The program will load in each predicted and ground truth trajectory, visualize them, and save the rendered frames.

Citation

If you use this code, please cite our work:

@inproceedings{RempeDynamics2020,
	author={Rempe, Davis and Sridhar, Srinath and Wang, He and Guibas, Leonidas J.},
	title={Predicting the Physical Dynamics of Unseen 3D Objects},
	journal={Proceedings of the Winter Conference on Applications of Computer Vision (WACV)},
	year={2020}
}