使用PLYWriter进行保存，代码如下：

#include <pcl/io/pcd_io.h>
#include <pcl/io/ply_io.h>
#include <pcl/console/print.h>
#include <pcl/console/parse.h>
#include <pcl/console/time.h>

using namespace pcl;
using namespace pcl::io;
using namespace pcl::console;

void
printHelp (int, char **argv)
{
  print_error ("Syntax is: %s [-format 0|1] [-use_camera 0|1] input.pcd output.ply\n", argv[0]);
}

bool
loadCloud (const std::string &filename, pcl::PCLPointCloud2 &cloud)
{
  TicToc tt;
  print_highlight ("Loading "); print_value ("%s ", filename.c_str ());

  tt.tic ();
  if (loadPCDFile (filename, cloud) < 0)
    return (false);
  print_info ("[done, "); print_value ("%g", tt.toc ()); print_info (" ms : "); print_value ("%d", cloud.width * cloud.height); print_info (" points]\n");
  print_info ("Available dimensions: "); print_value ("%s\n", pcl::getFieldsList (cloud).c_str ());

  return (true);
}

void
saveCloud (const std::string &filename, const pcl::PCLPointCloud2 &cloud, bool binary, bool use_camera)
{
  TicToc tt;
  tt.tic ();

  print_highlight ("Saving "); print_value ("%s ", filename.c_str ());
  
  pcl::PLYWriter writer;
  writer.write (filename, cloud, Eigen::Vector4f::Zero (), Eigen::Quaternionf::Identity (), binary, use_camera);
  
  print_info ("[done, "); print_value ("%g", tt.toc ()); print_info (" ms : "); print_value ("%d", cloud.width * cloud.height); print_info (" points]\n");
}

/* ---[ */
int
main (int argc, char** argv)
{
  print_info ("Convert a PCD file to PLY format. For more information, use: %s -h\n", argv[0]);

  if (argc < 3)
  {
    printHelp (argc, argv);
    return (-1);
  }

  // Parse the command line arguments for .pcd and .ply files
  std::vector<int> pcd_file_indices = parse_file_extension_argument (argc, argv, ".pcd");
  std::vector<int> ply_file_indices = parse_file_extension_argument (argc, argv, ".ply");
  if (pcd_file_indices.size () != 1 || ply_file_indices.size () != 1)
  {
    print_error ("Need one input PCD file and one output PLY file.\n");
    return (-1);
  }

  // Command line parsing
  bool format = true;
  bool use_camera = true;
  parse_argument (argc, argv, "-format", format);
  parse_argument (argc, argv, "-use_camera", use_camera);
  print_info ("PLY output format: "); print_value ("%s, ", (format ? "binary" : "ascii"));
  print_value ("%s\n", (use_camera ? "using camera" : "no camera"));

  // Load the first file
  pcl::PCLPointCloud2 cloud;
  if (!loadCloud (argv[pcd_file_indices[0]], cloud)) 
    return (-1);

  // Convert to PLY and save
  saveCloud (argv[ply_file_indices[0]], cloud, format, use_camera);

  return (0);
}

来源：PCL官方示例