Fine Wrinkling on Coarsely-Meshed Thin Shells

This code implements the paper Fine Wrinkling on Coarsely-Meshed Thin Shells.

Elastic Material Model (benchmarks)

The elastic material model is wrappered from libshell, where we implement a parallel version using TBB. See the files in "ElasticShell" for details

Wrinkled Tension Field (TFW) Model

As mentioned in the paper, we seperate the solver into two parts: base mesh extraction using tension field thoery (TFT), and wrinkle variable computation. The former one is implemented inside "ElasticShell". The later is inside "TFWShell".

Dependencies

• Libigl
• Polyscope
• TBB
• NASOQ
• Json (We include the json.hpp file in the external/json)
• Suite Sparse

All the dependencies are solved by Fetcontent, except Suite Sparse (See below for instruction) and NASOQ (included as a submodule).

Build with Suite-Sparse

For linux, you should use

sudo apt-get update -y
sudo apt-get install -y libsuitesparse-dev

For macOS, this can be done with Homebrew:

brew install suite-sparse

For windows, please follow the guidence provided in suitesparse-metis-for-windows. If you have anaconda installed, this part can be solved by:

conda install -c conda-forge suitesparse

To download and build

To build this project, you can use the following commands

    git clone --recursive https://github.com/zhenchen-jay/WrinkledTensionFields.git
    cd WrinkledTensionField
    mkdir build
    cd build
    cmake ..
    make -j4

important: Make sure you have --recursive when you clone the repository.

To run

You can use the following commands to run the program:

./bin/TFWShellCli_bin -i ../data/TFW/dress/dress2_TFW.json -o ../data/TFW/dress/results -r -u 3

The detailed parameters are listed below:

• -i/--input: path for input json file (.json), which contains the problem setup (see below for details).
• -o/--output: the folder for output results (ampliude, frequency and wrinkled mesh).
• -r/--reinitialization: reinitialize the amplitude and frequency based on the current strain.
• -u/--upsampleTimes: the upsampling (subdivision) times to recover the final wrinkled mesh.
• -n/--numIter: Number of iterations, default is 1000.
• -g/--gradTol: The tolerance for gradient norm termination, default is 1e-6.
• -x/--xTol: The tolerance of variable update termination, default is 0.
• -f/--fTol: The tolerance of function update termination, default is 0.
• -q/--quiet: The flag to turn off printing the optimization log, default is false.

JSON file

The setup json file has the following format:

• rest_mesh: The .obj file for the rest (coarse) mesh.
• base_mesh: The .obj file for the base (coarse) mesh.
• poisson_ratio: The Poisson's ratio
• thickness: Thickness (m)
• youngs_modulus: Young's modulus (Pa)
• amp_path: The .txt file to store the current/final amplitude file (per vertex value)
• phi_path: The .txt file to store the current/final phase file (per vertex value)
• dphi_path: The .txt file to store the current/final frequency file (per edge value)
• clamp: The flag to indicate whether we keep the clamped vertices clamped (force the ampltidue to be zero), default is true
• clamped_DOFs: The .dat file stores all the clamped vertices. (vid, x, y, z).
• nasoq_eps: The tolerance for NASOQ solver, default is 1e-6
• obs_mesh: The .obj file for the obstacle file.
• quadpoints: The number of quadrature point used to evaluate the integration, default is 3
• sff_type: The discrete second fundamental form type, default is midedgeTan (see libsell for details)
• rest_flat: The flag for flat (zero second fundamental form) rest mesh.

Compiling Issues

• It may take a while to compile on Windows, see libsell for possible solutions. Beside, you may encounter the miss of libopenblas.dll issue. In this case, please copy the libopenblas.dll inside the build/_deps/comiso-src/ext/OpenBLAS-v0.2.14-Win64-int64/bin and paste it into build/bin/Release. We also include pre-compiled executable files under the folder WindowsExe/Release.

• When compiling in MacOS with C++17, you may encounter this issue:

build/_deps/comiso-src/ext/gmm-4.2/include/gmm/gmm_domain_decomp.h:84:2: error: ISO C++17 does not allow 'register' storage class specifier [-Wregister]

To solve this, please remove the replace register double by double.

Input coase mesh

Although our TFWShellCli_bin can take any coarse mesh as input, as stated in our paper, the tension field results give the best final wrinkled mesh. To turn the any coarse shape into tension field result, you can try with libsell. We also provide an executable (ElasticShellCli_bin). Please refer the README.md file under apps/ElasticShellCli for details.

GUI

We also offer GUI versions of these two executable programs: ElaticShellGui_bin and TFWShellGui_bin. The inputs for these GUI versions are identical to those required for the command line counterparts.

More data

You can find more complicate data https://www.dropbox.com/sh/b33crodfwjbf982/AABhaIjJHhiIK4HeFMedpcgoa?dl=0