Octomap building in ROS

Pre-requisites

sudo apt-get install ros-melodic-octomap ros-melodic-octomap-msgs ros-melodic-octomap-ros ros-melodic-octomap-rviz-plugins ros-melodic-octomap-server ros-melodic-octomap-mapping ros-melodic-freenect-launch libfreenect-dev

Instructions for cloning and building (Optional)

Octomap_server is used to generate and save octomaps as .bt (binary) or .ot (oct-tree) files.

• cd catkin_ws/src
• git clone https://github.com/OctoMap/octomap_mapping
• git clone https://github.com/code-iai/iai_kinect2
• catkin_make

create a catkin package

• cd src/
• catkin_create_pkg cameras roscpp rospy std_msgs
• cd ..
• catkin_make

and add the following launch file, start_cameras.launch inside a launch folder

<launch>
  
     <include file="$(find kinect2_bridge)/launch/kinect2_bridge.launch">
       <arg name="base_name" value="ceiling_camera"/>
       <arg name="sensor" value="002608570547" />  <!-- Replace this line with your camera serial number -->
       <arg name="fps_limit" value="15" />
       <arg name="publish_tf" value="true" />
       <arg name="base_name_tf" value="ceiling_camera" />
     <!--  <arg name="output_frame" value="ceil" />   -->
     </include>

<node pkg="tf" type="static_transform_publisher" name="ceiling_cam_transform" args="
-0.12019394, -0.04154276,  1.53544738  0.64843474, -0.64567785,  0.28140082, -0.28887035 /world /ceiling_camera_link 100"/>  

</launch>

The procedures for building an octmap for visualization in Rviz are follows:

1. roslaunch camera_setup start_cameras.launch # to launch the kinect 3D sensor
2. roslaunch octomap_server octomap_mapping.launch # 2 things need to be changed 1) frame_id 2) remap cloud_in. check the forked octomap_mapping.launch here
3. rosrun rviz rviz
4. Add MarkerArray in Rviz and select the topic as /occupied_cells_vis_array. Set the same frame_id above (in 2) in the Global option –> Fixed frame in Rviz
5. rosrun octomap_server octomap_saver -f map_name.bt (or .ot) # to save the octomap

Visualize octomap in Rviz

1. Close all the above
2. roscore
3. rosrun rviz rviz
4. rosrun octomap_server octomap_server_node map_name.bt
5. Add MarkerArray in Rviz and select the topic as /occupied_cells_vis_array. Set the same frame_id as it was recorded in the Global option –> Fixed frame in Rviz. There might be a chance that the octomap wont show up. Then write frame id as map which should solve the problem