【三维视觉】TetWild / fTetWild学习：将任意mesh处理成流形水密的mesh

本文主要是介绍【三维视觉】TetWild / fTetWild学习：将任意mesh处理成流形水密的mesh，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！

项目地址

TetWild - Tetrahedral Meshing in the Wild
快速版本：Fast Tetrahedral Meshing in the Wild

2D版本：
TriWild: Robust Triangulation With Curve Constraints

快速版本的fTetWild

输入与输出

输入：任意网格：.off/.obj/.stl/.ply format
输出：保证是水密的
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其中.msh文件可以用gmesh打开
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这里的面片颜色代表的是每个面片与原始网格的误差，通过设置stop-energy来调节，默认的是8，当所有面片的最大误差都小于stop-energy时停止优化

参数含义

float-tetwild
Usage: ./FloatTetwild_bin [OPTIONS]Options:-h,--help                   Print this help message and exit-i,--input TEXT:FILE        Input surface mesh INPUT in .off/.obj/.stl/.ply format. (string, required)-o,--output TEXT            Output tetmesh OUTPUT in .msh format. (string, optional, default: input_file+postfix+'.msh')--tag TEXT:FILE             Tag input faces for Boolean operation.--op INT                    Boolean operation: 0: union, 1: intersection, 2: difference.-l,--lr FLOAT               ideal_edge_length = diag_of_bbox * L. (double, optional, default: 0.05)-e,--epsr FLOAT             epsilon = diag_of_bbox * EPS. (double, optional, default: 1e-3)--max-its INT               (for debugging usage only)--stop-energy FLOAT         Stop optimization when max energy is lower than this.--stage INT                 (for debugging usage only)--stop-p INT                (for debugging usage only)--postfix TEXT              (for debugging usage only)--log TEXT                  Log info to given file.--level INT                 Log level (0 = most verbose, 6 = off).-q,--is-quiet               Mute console output. (optional)--skip-simplify             skip preprocessing.--no-binary                 export meshes as ascii--no-color                  don't export color--not-sort-input            (for debugging usage only)--correct-surface-orientation(for debugging usage only)--envelope-log TEXT         (for debugging usage only)--smooth-open-boundary      Smooth the open boundary.--export-raw                Export raw output.--manifold-surface          Force the output to be manifold.--coarsen                   Coarsen the output as much as possible.--csg TEXT:FILE             json file containg a csg tree--use-old-energy            (for debugging usage only)--disable-filtering         Disable filtering out outside elements.--use-floodfill             Use flood-fill to extract interior volume.--use-general-wn            Use general winding number.--use-input-for-wn          Use input surface for winding number.--bg-mesh TEXT:FILE         Background mesh for sizing field (.msh file).--max-threads UINT          Maximum number of threads used

Smoothing open regions
Our method can fill gaps and holes but the tetmesh faces on those parts could be bumpy. We provide users an option to do Lapacian smoothing on those faces to get a smoother surface.
Envelope of size epsilon
Using smaller envelope preserves features better but also takes longer time. The default value of epsilon is b/1000, where b is the length of the diagonal of the bounding box.
Ideal edge length
Using smaller ideal edge length gives a denser mesh but also takes longer time. The default ideal edge length is b/20
Filtering energy
Our mesher stops optimizing the mesh when maximum energy is smaller than filtering energy. Thus, larger filtering energy means less optimization and sooner stopping. If you do not care about quality, then give a larger filtering energy would let you get the result earlier. The energy we used here is conformal AMIPS whose range is from 3 to +inf. The default filtering energy is 10.
💡 We suggest not to set filtering energy smaller than 8 for complex input.
Maximum number of optimization passes
Our mesher stops optimizing the mesh when the maximum number of passes is reached. The default number is 80.
bg-mesh
Sizing field Users can provide a background tetmesh in .msh format with vertex scalar field values stored. The scalar field values is used for controlling edge length. The scalars inside an element of the background mesh are linearly interpolated.
💡 Here is an example including input surface mesh, background mesh and output tetmeshes with/without sizing control.
Smoothing open regions
Our method can fill gaps and holes but the tetmesh faces on those parts could be bumpy. We provide users an option to do Lapacian smoothing on those faces to get a smoother surface.

我的私人总结

–no-color don’t export color，这里的颜色指的是给每个面片记录浮点的filtering energy

处理得到neural subdivision surfaces的输入网格的参数设置

./FloatTetwild_bin -i input_mesh_path -o  output_mesh_path_no_postfix -l 0.05 --e 0.0002 --manifold-surface --smooth-open-boundary

–l 0.05：更小的边长更精细，实测（0.05不到1min, 0.01需要2-3min, 0.005需要10+min)
Ideal edge length
Using smaller ideal edge length gives a denser mesh but also takes longer time. The default ideal edge length is b/20

–e 0.0002: 更小的值更好地保留特征
Envelope of size epsilon
Using smaller envelope preserves features better but also takes longer time. The default value of epsilon is b/1000, where b is the length of the diagonal of the bounding box.
–manifold-surface：保证流形，否则会出现非流形的顶点
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–smooth-open-boundary：使用拉普拉斯平滑来平滑孔洞填充后的面
原始网格

没有平滑

有平滑