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I'd like to know if there is a way to export the Point Cloud acquired with RGBD-6D-SLAM to a format usable in meshlab. That way I can triangulate it into a mesh and export it to whatever tool I want, eg Blender.

This is what I've already tried: Saving aqcuired data as .bag file rosbag record /rgbdslam/batch_clouds /tf

Extracting pointcloud data as .pcd file rosrun pcl_ros bag_to_pcd <bag_file_name> /rgbdslam/batch_clouds <destination_directory>

Here is where I'm stuck. If there is currently no way of doing this, I think I might try creating my own .pcd to .ply converter. I might be able to use the information at http://www.ros.org/wiki/pcl/Tutorials/Read%20Point%20Cloud%20data%20from%20PCD%20files for doing that.

Originally posted by duststorm on ROS Answers with karma: 91 on 2011-03-16

Post score: 2


4 Answers 4


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Hey Dust,

you could try editing the pcd file manually. In the end, it is just a text file with a header. Then, I assume there must be a way to import raw point clouds as text file with Meshlab.

For example, this is the beginning of sac_pane_test.pcd in pcl tests:

# .PCD v.5 - Point Cloud Data file format
FIELDS x y z w
SIZE 4 4 4 4
WIDTH 3283
DATA ascii
1.068 0.094721 -0.016231 0
1.061 -0.028772 0.060295 1
1.0623 -0.040527 0.061047 2
1.0662 -0.062634 0.068123 3


Originally posted by raphael favier with karma: 1382 on 2011-03-16

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#####PCD creation I don't really know the details of pcd export but can't you decide the format you want to use (binary or acsii)?

Did you create your pcd file by in the same way as in this tutorial? That way, you could save the pcd file directly inside RGBD-SLAM and not use a bag file. This should give you a better control on the pcd file you create.

Also have a look inside pcl/io, you will find the functions used to write pcd files from point clouds, maybe you can find how to force ascii mode.

#####Importing in Meshlab

I asked my colleague who actually used some point clouds I had generated with Kinect in Meshlab. All he did was:

  • Edit the pcd file (remove header and extra columns)
  • Change extension of the file to .asc

But as you said, you need a ascii format.

good luck :)


Originally posted by raphael favier with karma: 1382 on 2011-03-17

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As to answering my own question:

I made a small .ply recorder that listens to a topic and writes out any received PointClouds to a .ply file.

Usage: pcl_plyrecord <topic name>

common usage for rgbdslam would be: ./pcl_plyrecord /rgbdslam/batch_clouds

Now you will typically start rgbdslam and record something with it (CTRL+P). Now, to get it to record a usable .ply file, "send" the data with the rgbdslam tool (CTRL+S). This will send the acquired point cloud to the previously mentioned topic and will make it record to a .ply file.

It will output to output.ply

CTRL+C to stop the program (try to stop it when no new data is coming in, or your output file might miss some)

WARNING: It will overwrite output.ply every time you start the program!

The program records xyzrgb type pointclouds, like the ones rgbdslam outputs. If you import the .ply in meshlab you will have a pointmap with color. Just what we need! :)

You can find the source package here. It contains the source and a buildscript and readme for quick compiling. (read the readme!!)

Or for those who just want to have a look at the source:


#include <ros/ros.h>
#include <pcl_ros/point_cloud.h>
#include <pcl/point_types.h>
#include <boost/foreach.hpp>
#include <stdio.h> 
#include "pcl_plyrecord.h"
#include <math.h>
//#include "rply.h"

typedef pcl::PointCloud<pcl::PointXYZRGB> PointCloud;

int count = 0;
FILE *file;
long int HEADER_COUNT_POS = 0;

 * Add one point to output .ply file
 * Point will be omitted if it contains NaN coordinates
void addPoint(const float x, const float y, const float z, const float rgb)
    // Filter out points with NaN coordinates
    if(isnan(x) || isnan(y) || isnan(z) || isnan(rgb))
        return; // one of the values is NaN

    RGBValue color = RGBValue();
    color.float_value = rgb;
    unsigned char red = color.Red;
    unsigned char green = color.Green;
    unsigned char blue = color.Blue;

    fprintf(file, "%f %f %f %u %u %u\n", x, y, z, red, green, blue);

 * Write initial header of .ply file
 * Vertices count will be set to 0
void writeheader(void)
    fprintf (file, "ply\n");
    fprintf (file, "format ascii 1.0\n");
    fprintf (file, "comment Created with pcl_plyrecord\n");
    HEADER_COUNT_POS = ftell(file); // store location of vertices count
    fprintf (file, "element vertex %-10i\n", 0); // with extra padding for easy overwrite later on
    fprintf (file, "property float x\n");
    fprintf (file, "property float y\n");
    fprintf (file, "property float z\n");
    fprintf (file, "property uchar red\n");
    fprintf (file, "property uchar green\n");
    fprintf (file, "property uchar blue\n");
    fprintf (file, "end_header\n");

 * Overwrite the vertices count in the header at the top of the .ply file
 * Because of extra padding to the number, larger numbers can always be written in-place
 * File pointer is set to the end of the file again afterwards
void correctHeader(void)
    fseek(file, HEADER_COUNT_POS, SEEK_SET);
    fprintf (file, "element vertex %-10i\n", count);
    fseek(file, 0, SEEK_END);

 * Process a new incoming pointcloud
 * After adding all points of the cloud the vertices count in the header is altered
 * Interrupting the program before the header is altered will only make available
 * the vertices up to the previous fully processed pointcloud.
void callback(const PointCloud::ConstPtr& msg)
//  printf ("Cloud: width = %d, height = %d\n", msg->width, msg->height);
    BOOST_FOREACH (const pcl::PointXYZRGB& pt, msg->points)
    addPoint(pt.x, pt.y, pt.z, pt.rgb);


int main(int argc, char** argv)
    if(argc < 2) {
        printf ("Specify topic to record as parameter.\n");
    ros::init(argc, argv, "pcl_plyrecord");

    file = fopen("output.ply", "w");

    ros::NodeHandle nh;
    ros::Subscriber sub = nh.subscribe<PointCloud>(argv[1], 1, callback);


typedef union
    struct /*anonymous*/
        unsigned char Blue;
        unsigned char Green;
        unsigned char Red;
        unsigned char Alpha;
    float float_value;
    long long_value;
} RGBValue;

The most 'twiddly' part was to update the header of the .ply file, since the number of vertices has to be known at the start of the file. The header is updated after every full pointcloud that is processed. This means that if you CTRL + C before a pointcloud is fully processed, the header won't be updated and meshlab will only import vertices till the last full pointcloud that got processed.

Originally posted by duststorm with karma: 91 on 2011-03-22

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Post score: 2

Original comments

Comment by Shark on 2011-05-05:
What you proposed above about also recording the transform is correct. However, this discussion is kind of moot now with the new version of rgbdslam, which let's to directly save the accumulated point cloud to .pcd or .ply

Comment by duststorm on 2011-04-21:
If someone knows the correct workings of the transform and could explain, I could fix the code to account for transformations.

Comment by duststorm on 2011-04-21:
Maybe the fix would be to also record the /transform topic, extract the proper transformation information for an incoming pointcloud and multiply that pointcloud (or each point in the pointcloud) with the proper transformation matrix. I don't know ROS that well to be able to answer for sure.

Comment by duststorm on 2011-04-21:
Do you think so? I didn't notice that yet in my resulting files, but I must admit I haven't really been experimenting with it a lot. I do know however that when trying bag to pcd conversion there might be compaints about missing /transform data or such.

Comment by Shark on 2011-04-14:
I've implemented your code, but I think there is a slight problem. You do not account for the transform anywhere, so the pointclouds are not mapped correctly in your combined ply file.

Comment by duststorm on 2011-03-24:
As a sidenote: the output file could be made more compact if the program would output a binary instead of an ascii .ply file. Of course that makes it a little harder to read and parse afterwards. Meshlab supports both.


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It is not exclusive to ROS, but Nicolas Burrus has a nice stand alone ogram you can use to easily convert captured Kinect 3D room scans into .ply files that can be imported into Meshlab. You could then potentially use that saved into to come back to ros for various applications.

Here is the link to his site:


Originally posted by Scott with karma: 693 on 2011-04-15

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Post score: 1

Original comments

Comment by raphael favier on 2011-04-15:
Thanks for the hint


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