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Run built-in examples

There are some built-in examples defined in the examples/ directory. Once the software is installed, it will create an excutable file in the build/bin directory.

Run an example using the following command in the root directory. The results will be stored in tmp/out/ directory after the running of the example, and can be visualized in paraview.

./build/bin/netdem_example_random_packing

python3 example/00_random_packing/pynetdem_1_gjk_solver.py

Reconstruct mesh of particles and walls

For irregular-shaped particles, use the following command to generate the results with particles represented by triangle meshes.

./build/bin/netdem_tool_point2mesh [in.vtk] [out.vtk] [shape_dir]

In case one need to do the generation in batch, the following command can be used

./scripts/batch_data_point2mesh.sh [in_dir] [out_dir] [shape_dir] [0, 1]

Option [0, 1] is for importing shape informaiton, such that 0 indicates using the json shape info (i.e., shape_000_000000000000000.json), 1 indicates using stl shape files. For json shape info, please specify the exact file name for [shape_dir], whereas the directory shape/ for stl shape info.

or easier

./scripts/auto_mesh_particle.sh [out_dir] [0, 1, or 2]
./scripts/auto_mesh_wall.sh [out_dir] [0, 1, or 2]

Option [0, 1, or 2] is for importing shape informaiton, such that 0 indicates using the 0-time-step shape info (i.e., shape_000_000000000000000.json) in the shape/ sub-directory of the result root, 1 indicates using STL shape files, whereas 2 indicates using time specific shape info (e.g., shape_000_0000000xxxxxxxxx.json).

Customized simulation

Please follow the built-in examples to write the c++ or python scripts.

Visualize in paraview

Results can be dumped as VTK files, which can be visualized in paraview.

Spherical particles

  • Import particle info into paraview;
  • Set Representation to Point Gaussian, and adjust the radius;
  • In case particles are of various sizes, enable Toggle advanced properties, enable Use Scale Array, select the proper Scale Array Component, and adjust the Range.

General particles and walls

Contact force chain

  • Enable dump contact force by set: data_dump.dump_contact_info = true;
  • Import contact info into paraview;
  • Add a tube filter to the contact force data in paraview, and adjust the radius of the contact tubes.

Ray tracing

  • Enable Ray Tracing at the end of Properties section;
  • Change the Back end to OsPRay pathtracer;
  • Increase the Samples Per Pixel, which gives fair results with a value 5 in reasonble rendering time;
  • Set the Background mode to Backplase, which is while as suggested.
  • One can play with the Material options in the middle-while of the Properties section.

Create animation

  • In paraview, go File → Save Animation;
  • Select the avi option and specify the name;
  • Suggest to set the image resolution with 1920 x 1080, i.e., 1080p, and Set the Frame Rate to 24 (a minimal value to give fluent animation);
  • Compress the avi animation with third-party tools, such as ffmpeg or Tencent Cloud;
    • For Tencent Cloud, suggested procedures (in Chinese):
    • 选择云产品云点播，在媒资管理 → 音视频管理中，上传视频;
    • 上传视频后，选择待处理的视频，进行视频处理，建议选择TESHD-H264-MP4-720P转码模板;
    • 点击右侧的管理，可查看视频封面和视频播放地址等链接，可用于网页制作.

Post-process

We have a side-repository that provides some matlab or python scripts for post-process (e.g., VTK io, stress-strain, spherical histograms of contact anisotropy).

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