Getting Started with RViz in ROS 2 Humble

Introduction to RViz

For those beginning their robotics journey using ROS 2 Humble, RViz will soon become one of your most frequently used tools. This guide will help you understand:

• What RViz is and its role in ROS development

• Why it's a critical component for robot visualization

• How to leverage it to monitor sensor data and robot movements in real-time

What Is RViz?

RViz (ROS Visualization) is a powerful 3D visualization tool that lets you peer into your robot’s "mind." Whether you’re working with:

• Sensor data (LiDAR, IMU, etc.),

• Camera feeds,

• Robot motion planning,

RViz brings your robot’s world to life, making debugging, development, and learning far more intuitive.

RViz Setup Process for ROS2 Humble

Prerequisites

Before starting this tutorial, ensure you have:

• A working installation of ROS 2 Humble (Desktop version) Beginners guide to ROS2 Humble Installation

• Ubuntu 22.04 LTS (recommended for ROS 2 Humble)

• Basic knowledge of how to use the Linux terminal

• Your ROS 2 workspace created and sourced (e.g., source install/setup.bash) Creating Workspace and package

NOTE: RViz2 (ROS Visualization Tool) is typically installed automatically when you install the ROS2 Humble desktop version. Here's how to verify and set it up:

Checking RViz2 Installation

To verify if RViz2 is already installed on your system, run the following command in your terminal:

ros2 pkg list | grep rviz2

If the output shows rviz2, then RViz is properly installed on your system.

Installing RViz2

If RViz2 isn't installed, you can install it using one of these methods:

Install only RViz2

sudo apt install ros-humble-rviz2

Install full ROS2 Desktop (includes RViz2)

sudo apt install ros-humble-desktop

Launching RViz2

Once installed, you can launch RViz2 by running:

rviz2

You will see the following window:

Possible Errors and Solutions During Installation and Launching

Error: Command ‘rviz2’ Not Found

Cause: This typically occurs because the ROS 2 environment hasn’t been sourced in your terminal.

Solution:
Temporary Fix: Source the ROS 2 environment manually in your current terminal:

source /opt/ros/humble/setup.bash

(Note: You’ll need to repeat this every time you open a new terminal.)

• Permanent Fix: Add the sourcing command to your .bashrc file to automate this process:

echo "source /opt/ros/humble/setup.bash" >> ~/.bashrc

• After running this, either restart your terminal or run source ~/.bashrc to apply changes immediately.

Understanding the RViz Interface

When you first launch RViz, you’ll see this layout:

1. 3D View (Center)

   • The large black window is your 3D visualization area.

   • Currently empty since no displays are active.

2. Displays Panel (Left Sidebar)

   • Lists all loaded displays (e.g., sensors, robot models).

   • Default contents:

     • Global Options (configuration settings)

     • Grid (reference plane; we’ll cover this later).

3. Tools & Properties (Right Sidebar)

   • Additional panels for:

     • View controls

     • Tool properties

     • Visualization settings.

Adding a New Display

Click the Add button at the bottom of the Displays panel.

This will pop up the new display dialog:

• The list at the top contains the display type

• The type details what kind of data this display will visualize

• The text box in the middle gives a description of the selected display type

• Finally, you must give the display a unique name

• If you have, for example, two laser scanners on your robot, you might create two Laser Scan displays named "Laser Base" and "Laser Head"

Example: Using RViz’s "Add" Feature to Visualize a Robot

One of RViz’s most powerful features is the ability to dynamically add visualizations. Let’s walk through a practical example—loading your URDF-based robot model:

1. Open the Displays Panel

   • All visualization management happens in the left-side Displays panel.

2. Click "Add"

   • Find this button at the panel’s bottom—it’s your gateway to every visualization type.

3. Select "RobotModel"

   • From the list, choose this option to load your robot’s URDF representation.

4. Verify the Configuration

   • RViz auto-populates:

     • Joint hierarchies

     • Link geometries

     • TF frames

   • Critical Check: Ensure the Fixed Frame (under Global Options) matches your robot’s base frame (e.g., base_link).

5. Finalize with "OK"

   • Your robot should now appear in the 3D view, ready for inspection!

This simple "Add" workflow unlocks:

• Instant Validation

  • Confirm your URDF’s accuracy before hardware testing.

• TF Debugging

  • Visually verify frame relationships and detect misalignments.

• Sensor Integration

  • Later, add displays like LaserScan or PointCloud2 to see sensor data in context.

Troubleshooting Tip: If the robot is invisible, check:

• URDF file permissions/paths

• robot_state_publisher is active (ros2 topic echo /robot_description)

• TF tree integrity (ros2 run tf2_tools view_frames.py)

Configuring Display Properties

Every display in RViz includes customizable properties that control its visualization. These appear as adjustable parameters when a display is selected.

Examples of display properties include:

• Color schemes for point clouds or markers

• Topic selection for sensor data streams

• Alpha values (transparency) for rendered objects

• Frame settings for coordinate system alignment

Display Status in RViz

Each display in RViz includes a status indicator to show its operational state. The possible status values are:

• OK (Functioning normally)

• Warning (Potential issues detected)

• Error (Serious problem preventing display)

• Disabled (Display currently turned off)

You can identify the status through:

1. The background color in the display's title bar

2. The explicit status message visible when expanding the display (under the Status category)

Views Panel in RViz

RViz offers multiple camera view types to visualize your robot's environment:

1. Projection Types

   • Perspective: Standard 3D view with depth perception (objects appear smaller with distance)

   • Orthographic: 2D projection without perspective distortion (useful for top-down views)

2. Control Methods

   • Orbit: Rotate around a fixed point

   • FPS: First-person shooter-style movement

   • Top-down: Fixed overhead perspective

RViz Visualization Tools Overview

RViz provides an interactive toolbar containing several specialized tools for working with your 3D visualization environment. These tools enable you to:

• Navigate and inspect your robot's data from different perspectives

• Interact with and measure elements in the 3D space

• Configure and analyze various aspects of your visualization

The main toolbar tools include:

1. Camera Controls:

   • Focus Camera tool

   • Move Camera tool

   • Orbit View tool

2. Measurement Tools:

   • Measure tool (for distance calculations)

   • Publish Point tool

3. Interaction Tools:

   • Select Tool

   • 2D Goal Press tool

   • 2D Pose Estimate tool

For comprehensive details about each tool's functionality, refer to RViz's built-in documentation by selecting:
Help → Show Help Panel

Ready to Master RViz?

You’ve now taken your first steps with RViz’s core features—but there’s so much more to explore! To dive deeper:

🔹 Explore the Documentation

• Access detailed tool explanations via Help → Show Help Panel in RViz

• Refer to the https://docs.ros.org/en/humble/Tutorials/Configuring-RViz2.html

🔹 Watch Tutorials

• The ROS community offers excellent video guides—search for "ROS 2 Humble RViz tutorial" on platforms like YouTube

🔹 Experiment Hands-On

• Try visualizing different sensor data (LiDAR, cameras, IMU)

• Customize displays for your robot’s specific needs

Remember: Every expert started where you are now. Keep exploring, and soon you’ll be leveraging RViz like a pro!

References.

1. https://docs.ros.org/en/humble/Tutorials/Intermediate/RViz/RViz-User-Guide/RViz-User-Guide.html

2. Ros2 Rviz tutorial for robotics

3. RVizs tutorial

4. Ros2 RVizs tutorial