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前言

本文分享CGAL的Polygon_mesh_processing_Examples样例中的isotropic_remeshing_example，该样例主要介绍了如何生成各向同性的三角网格，希望对各位小伙伴有所帮助！

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可以收获到以下知识：

1. 读取/打开本地三维模型，支持的模型包括*.off *.obj、*.stl、*.ply 、*.ts 、*.vtp。

2. 保存三维模型。

3. 对三维模型进行Remesh

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目录

前言

1. isotropic_remeshing_example

2. 重要方法

2.1 读取数据

2.2 各向同性Remesh

 2.3 保存数据

结论：

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1. isotropic_remeshing_example

#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Surface_mesh.h>
#include <CGAL/Polygon_mesh_processing/remesh.h>
#include <CGAL/Polygon_mesh_processing/border.h>
#include <CGAL/Polygon_mesh_processing/IO/polygon_mesh_io.h>

#include <boost/iterator/function_output_iterator.hpp>

#include <iostream>
#include <string>
#include <vector>

typedef CGAL::Exact_predicates_inexact_constructions_kernel   K;
typedef CGAL::Surface_mesh<K::Point_3>                        Mesh;

typedef boost::graph_traits<Mesh>::halfedge_descriptor        halfedge_descriptor;
typedef boost::graph_traits<Mesh>::edge_descriptor            edge_descriptor;

namespace PMP = CGAL::Polygon_mesh_processing;

struct halfedge2edge
{
  halfedge2edge(const Mesh& m, std::vector<edge_descriptor>& edges)
    : m_mesh(m), m_edges(edges)
  {}
  void operator()(const halfedge_descriptor& h) const
  {
    m_edges.push_back(edge(h, m_mesh));
  }
  const Mesh& m_mesh;
  std::vector<edge_descriptor>& m_edges;
};

int main(int argc, char* argv[])
{
  //const std::string filename = (argc > 1) ? argv[1] : CGAL::data_file_path("meshes/pig.off");
    const std::string filename = "cup.stl";

  Mesh mesh;
  if(!PMP::IO::read_polygon_mesh(filename, mesh) || !CGAL::is_triangle_mesh(mesh))
  {
    std::cerr << "Invalid input." << std::endl;
    return 1;
  }

  double target_edge_length = (argc > 2) ? std::stod(std::string(argv[2])) : 0.04;
  target_edge_length = 1.;
  unsigned int nb_iter = 3;

  std::cout << "Split border...";

  std::vector<edge_descriptor> border;
  PMP::border_halfedges(faces(mesh), mesh, boost::make_function_output_iterator(halfedge2edge(mesh, border)));
  PMP::split_long_edges(border, target_edge_length, mesh);

  std::cout << "done." << std::endl;
  std::cout << "Start remeshing of " << filename
    << " (" << num_faces(mesh) << " faces)..." << std::endl;

  PMP::isotropic_remeshing(faces(mesh), target_edge_length, mesh,
                           CGAL::parameters::number_of_iterations(nb_iter)
                                            .protect_constraints(true)); //i.e. protect border, here

  std::cout << "Remeshing done." << std::endl;

  CGAL::IO::write_polygon_mesh("cupcgal_mesh.stl", mesh, CGAL::parameters::stream_precision(17));

  return 0;
}

2. 重要方法

2.1 读取数据

PMP::IO::read_polygon_mesh(filename, mesh)

2.2 各向同性Remesh

  PMP::isotropic_remeshing(faces(mesh), target_edge_length, mesh,
                           CGAL::parameters::number_of_iterations(nb_iter)
                                            .protect_constraints(true)); //i.e. protect border, here

 2.3 保存数据

CGAL::IO::write_polygon_mesh("cupcgal_mesh.stl", mesh, CGAL::parameters::stream_precision(17));

结论：

感谢各位小伙伴的点赞+关注，小易会继续努力分享，一起进步！

你的赞赏是我的最最最最大的动力(＾Ｕ＾)ノ~ＹＯ