Using 3D map as a model in Gazebo

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To load the octomap in Gazebo, you have to get a COLLADA file first. To get it, you can can follow these steps:

1. First, save the octomap using the node provided by the octomap_server package itself:

   rosrun octomap_server octomap_saver octomap_model_test.bt

2. Then, run provided by the octomap library, inside octomap/bin, to obtain the corresponding .pcd file:

   ./octree2pointcloud ~/octomap_model_test.bt octomap_model_test.pcd

3. To get the COLLADA (.dae) file that can be loaded into Gazebo, the way I know is converting the .pcd to a .ply file first. The PCL library offers an Ubuntu command for this task:

   pcl_pcd2ply octomap_model_test.pcd octomap_model_test.ply

4. Once you have the .ply file, it can be converted to a .dae file with, for example, MeshLab:

   1. Install meshlab.

      sudo apt update sudo apt install meshlab

   2. Open meshlab.

   3. 'File' > 'Import Mesh (Ctrl+I)'.

   4. 'Export Mesh As...'.
      Select 'Collada File Format (*.dae)'.

Once you have the model with a .dae format, you can load it in Gazebo as usual. I posted an example here of how to do it, where I also suggest how to keep the texture of the PLY file with COLLADA. However, I don't know how to save the octomap keeping the colour of the voxels. I'd appreciate it if someone has any information on this.

Hope it helps!

@leodomitrovic Yes it is possible but you need some processing to be able to include it in a Gazebo world. To include it you will need to have a 3D mesh of your map as a COLLADA or .obj file in order to be able to export the mesh in the visual/collision tag.

I am not really into those packages you mentioned but it seems that with those nodes you usually obtain OccupancyGrids, that is 2D maps. If you manage to obtain from these nodes a .ply or .pcd file accumulating the pointclouds you can process them in meshlab and generate a 3D model from the pointcloud points (vertices). Then export it as .dae/.obj in a SDF model.

There is a good gist page that show how to do that once you have the pointcloud data stored in a file.

Hope that helps.

Regards.