Motion Capture Tutorial

Prerequisite

1. Setting markers for the object you want to track

2. Connect to the Magicc network

   Turn Between the lab conference room and the flight room (146A and 146C), there's a Netgear box used for the mocap system. To turn it on, press the power button marked "MoCap" that is under the desk. Pressing the wrong button might cause serious problems! And don't forget to turn it off when you're finished.

3. Open Motive (can be found on the Windows desktop). Make sure Motive is not blocked by the firewall!

Tracking the vehicle/object

1. In the menu, select "View -> Assets Pane".

2. On the left sidebar check the boxes, and you should see the markers on the perspective view. Choose the markers you want to track.

   In this case, "DemonstrationCopter" is being tracked (containing four markers).

Data Collecting with ROS

1. Download the vrpn_client_ros package.

In the src of your workspace, run:

 git clone https://gitlab.magiccvs.byu.edu/lab/vrpn_client_ros2.git

And in your workspace, build the package:

 colcon build

1. Run the vrpn_client_ros node.

    ros2 run vrpn_client_ros vrpn_client_node 
   

[INFO] [1726270601.321879825] [vrpn_client_node]: Connecting to VRPN server at localhost:3883
[INFO] [1726270602.324711875] [vrpn_client_node]: Connection established

1. The tracked object's pose information is publishing to your device through ROS topics.

    ros2 topic list
   

   /DemonstrationCopter/pose
   /DemonstrationCopter/pose_enu
   /DemonstrationCopter/pose_ned
   /parameter_events
   /rosout
   

   The topic DemonstrationCopter_enu publishes the pose in the ENU frame (East, North, Up), and the topic DemonstrationCopter_ned publishes the pose in the NED frame (North, East, Down).

 ros2 topic echo /DemonstrationCopter_ned

header:
  seq: 1810
  stamp:
    secs: 1720634981
    nsecs: 653036405
  frame_id: "optitrack_ned"
pose:
  position:
    x: 0.557237863541
    y: 3.70402407646
    z: -1.14867293835
  orientation: 
    x: -0.0940773898464
    y: -0.711429558216
    z: 0.676397042416
    w: 0.165845259493
---

Data Collecting with the Motive Record Function

1. Make sure you're under the LIVE mode. Click on the red recording button. Click on it again to end the recording.

2. Click on "EDIT" to switch to the EDIT mode. Select "File -> Export Tracking Data", and save the file in the CSV format.

   Your file should look like this:

When you are finished, be sure to unplug the mocap system box from power.