Frames in rviz

1. Install the ROS package agni-tf-tools

sudo apt install ros-<distro>-agni-tf-tools

2. Source your ROS environment, and start roscore as well as rviz

source /opt/ros/<distro>/setup.bash
roscore &
rosrun rviz rviz

3. Add new displays, namely TF and Static Transform Publisher

Using several transform publishers, build up a transformation tree like this:

world
 ↳ T1 → R1
 ↳ R2 → T2

where translations (T) are 0.5m along the y-axis, and rotations (R) are -90° about the z-axis (see image).

4. Using the TF display, read out the following relative transforms

• world → R1
• R1 → world
• R1 → T2

To this end, define rviz's fixed frame (in Global Options) to the parent frame and read out the corresponding transformation of the child frame in TF display's frames list.

Background: rviz displays all data with respect to a given fixed frame. If this reference frame is changed, all coordinate representations change correspondingly.