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| === tf Debugging === The tf debugging tools are in the tf package inside the bin directory or the scripts directory. * '''tf_echo''' - tf echo prints to screen the transform between two coordinate frames specified by the user. E.g. to print the transform between the base_link and the torso_lift_link: . {{{ rosrun tf tf_echo /base_link /torso_lift_link}}}. The expected output looks something like this . {{{ Success at 82.356000000 [0.000000 0.000000 0.000000 1.000000] Euler(0.000000 -0.000000 0.000000) Translation: [-0.050000 0.000000 0.739241] Success at 82.576000000 [0.000000 0.000000 0.000000 1.000000] Euler(0.000000 -0.000000 0.000000) Translation: [-0.050000 0.000000 0.739158] Success at 82.807000000 }}} * '''view_frames''' - This tool creates a pdf file named ''frames.pdf'' in the present working directory that contains the graphical representation of the tf tree. A typical example of this file while running on the robot can be found [[attachment:tf_view_frames_example.pdf|here]]. . {{{ rosrun tf view_frames }}} * '''tf_monitor''' - This tool monitors the link between two frames and prints information about how often the link is being updated inside the tf tree. . {{{ ./tf_monitor base_link torso_lift_link }}} For more information on using the tf tools, follow this link. |
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Package Summary
tf is a package that lets the user keep track of multiple coordinate frames over time. tf maintains the relationship between coordinate frames in a tree structure buffered in time, and lets the user transform points, vectors, etc between any two coordinate frames at any desired point in time.
- Author: Tully Foote, Eitan Marder-Eppstein, Wim Meeussen
- License: BSD
- Repository: ros-pkg
- Source: hg https://kforge.ros.org/geometry/geometry
Package Summary
tf is a package that lets the user keep track of multiple coordinate frames over time. tf maintains the relationship between coordinate frames in a tree structure buffered in time, and lets the user transform points, vectors, etc between any two coordinate frames at any desired point in time.
- Author: Tully Foote, Eitan Marder-Eppstein, Wim Meeussen
- License: BSD
- Source: hg https://kforge.ros.org/geometry/geometry (branch: electric-devel)
Package Summary
tf is a package that lets the user keep track of multiple coordinate frames over time. tf maintains the relationship between coordinate frames in a tree structure buffered in time, and lets the user transform points, vectors, etc between any two coordinate frames at any desired point in time.
- Author: Tully Foote, Eitan Marder-Eppstein, Wim Meeussen
- License: BSD
- Source: hg https://kforge.ros.org/geometry/geometry (branch: fuerte_devel)
Package Summary
tf is a package that lets the user keep track of multiple coordinate frames over time. tf maintains the relationship between coordinate frames in a tree structure buffered in time, and lets the user transform points, vectors, etc between any two coordinate frames at any desired point in time.
- Maintainer status: maintained
- Maintainer: Tully Foote <tfoote AT willowgarage DOT com>
- Author: Tully Foote, Eitan Marder-Eppstein, Wim Meeussen
- License: BSD
- Source: git https://github.com/ros/geometry.git (branch: groovy-devel)
Package Summary
tf is a package that lets the user keep track of multiple coordinate frames over time. tf maintains the relationship between coordinate frames in a tree structure buffered in time, and lets the user transform points, vectors, etc between any two coordinate frames at any desired point in time.
- Maintainer status: maintained
- Maintainer: Tully Foote <tfoote AT osrfoundation DOT org>
- Author: Tully Foote, Eitan Marder-Eppstein, Wim Meeussen
- License: BSD
- Source: git https://github.com/ros/geometry.git (branch: hydro-devel)
Package Summary
tf is a package that lets the user keep track of multiple coordinate frames over time. tf maintains the relationship between coordinate frames in a tree structure buffered in time, and lets the user transform points, vectors, etc between any two coordinate frames at any desired point in time.
Migration: Since ROS Hydro, tf has been "deprecated" in favor of tf2. tf2 is an iteration on tf providing generally the same feature set more efficiently. As well as adding a few new features.
As tf2 is a major change the tf API has been maintained in its current form. Since tf2 has a superset of the tf features with a subset of the dependencies the tf implementation has been removed and replaced with calls to tf2 under the hood. This will mean that all users will be compatible with tf2. It is recommended for new work to use tf2 directly as it has a cleaner interface. However tf will continue to be supported for through at least J Turtle.
- Maintainer status: maintained
- Maintainer: Tully Foote <tfoote AT osrfoundation DOT org>
- Author: Tully Foote, Eitan Marder-Eppstein, Wim Meeussen
- License: BSD
- Source: git https://github.com/ros/geometry.git (branch: indigo-devel)
Package Summary
tf is a package that lets the user keep track of multiple coordinate frames over time. tf maintains the relationship between coordinate frames in a tree structure buffered in time, and lets the user transform points, vectors, etc between any two coordinate frames at any desired point in time.
Migration: Since ROS Hydro, tf has been "deprecated" in favor of tf2. tf2 is an iteration on tf providing generally the same feature set more efficiently. As well as adding a few new features.
As tf2 is a major change the tf API has been maintained in its current form. Since tf2 has a superset of the tf features with a subset of the dependencies the tf implementation has been removed and replaced with calls to tf2 under the hood. This will mean that all users will be compatible with tf2. It is recommended for new work to use tf2 directly as it has a cleaner interface. However tf will continue to be supported for through at least J Turtle.
- Maintainer status: maintained
- Maintainer: Tully Foote <tfoote AT osrfoundation DOT org>
- Author: Tully Foote, Eitan Marder-Eppstein, Wim Meeussen
- License: BSD
- Source: git https://github.com/ros/geometry.git (branch: indigo-devel)
Package Summary
tf is a package that lets the user keep track of multiple coordinate frames over time. tf maintains the relationship between coordinate frames in a tree structure buffered in time, and lets the user transform points, vectors, etc between any two coordinate frames at any desired point in time.
Migration: Since ROS Hydro, tf has been "deprecated" in favor of tf2. tf2 is an iteration on tf providing generally the same feature set more efficiently. As well as adding a few new features.
As tf2 is a major change the tf API has been maintained in its current form. Since tf2 has a superset of the tf features with a subset of the dependencies the tf implementation has been removed and replaced with calls to tf2 under the hood. This will mean that all users will be compatible with tf2. It is recommended for new work to use tf2 directly as it has a cleaner interface. However tf will continue to be supported for through at least J Turtle.
- Maintainer status: maintained
- Maintainer: Tully Foote <tfoote AT osrfoundation DOT org>
- Author: Tully Foote, Eitan Marder-Eppstein, Wim Meeussen
- License: BSD
- Source: git https://github.com/ros/geometry.git (branch: indigo-devel)
Package Summary
tf is a package that lets the user keep track of multiple coordinate frames over time. tf maintains the relationship between coordinate frames in a tree structure buffered in time, and lets the user transform points, vectors, etc between any two coordinate frames at any desired point in time.
Migration: Since ROS Hydro, tf has been "deprecated" in favor of tf2. tf2 is an iteration on tf providing generally the same feature set more efficiently. As well as adding a few new features.
As tf2 is a major change the tf API has been maintained in its current form. Since tf2 has a superset of the tf features with a subset of the dependencies the tf implementation has been removed and replaced with calls to tf2 under the hood. This will mean that all users will be compatible with tf2. It is recommended for new work to use tf2 directly as it has a cleaner interface. However tf will continue to be supported for through at least J Turtle.
- Maintainer status: maintained
- Maintainer: Tully Foote <tfoote AT osrfoundation DOT org>
- Author: Tully Foote, Eitan Marder-Eppstein, Wim Meeussen
- License: BSD
- Source: git https://github.com/ros/geometry.git (branch: indigo-devel)
Package Summary
tf is a package that lets the user keep track of multiple coordinate frames over time. tf maintains the relationship between coordinate frames in a tree structure buffered in time, and lets the user transform points, vectors, etc between any two coordinate frames at any desired point in time.
Migration: Since ROS Hydro, tf has been "deprecated" in favor of tf2. tf2 is an iteration on tf providing generally the same feature set more efficiently. As well as adding a few new features.
As tf2 is a major change the tf API has been maintained in its current form. Since tf2 has a superset of the tf features with a subset of the dependencies the tf implementation has been removed and replaced with calls to tf2 under the hood. This will mean that all users will be compatible with tf2. It is recommended for new work to use tf2 directly as it has a cleaner interface. However tf will continue to be supported for through at least J Turtle.
- Maintainer status: maintained
- Maintainer: Tully Foote <tfoote AT osrfoundation DOT org>
- Author: Tully Foote, Eitan Marder-Eppstein, Wim Meeussen
- License: BSD
- Source: git https://github.com/ros/geometry.git (branch: melodic-devel)
Package Summary
tf is a package that lets the user keep track of multiple coordinate frames over time. tf maintains the relationship between coordinate frames in a tree structure buffered in time, and lets the user transform points, vectors, etc between any two coordinate frames at any desired point in time.
Migration: Since ROS Hydro, tf has been "deprecated" in favor of tf2. tf2 is an iteration on tf providing generally the same feature set more efficiently. As well as adding a few new features.
As tf2 is a major change the tf API has been maintained in its current form. Since tf2 has a superset of the tf features with a subset of the dependencies the tf implementation has been removed and replaced with calls to tf2 under the hood. This will mean that all users will be compatible with tf2. It is recommended for new work to use tf2 directly as it has a cleaner interface. However tf will continue to be supported for through at least J Turtle.
- Maintainer status: maintained
- Maintainer: Tully Foote <tfoote AT osrfoundation DOT org>
- Author: Tully Foote, Eitan Marder-Eppstein, Wim Meeussen
- License: BSD
- Source: git https://github.com/ros/geometry.git (branch: noetic-devel)
Contents
What does tf do? And why should I use tf?
You want to see what tf can do instead of just reading about it? Check out the tf introduction demo.
A robotic system typically has many 3D coordinate frames that change over time, such as a world frame, base frame, gripper frame, head frame, etc. Tf keeps track of all these frames over time, and allows you to ask questions like:
- Where was the head frame relative to the world frame, 5 seconds ago?
- What is the pose of the object in my gripper relative to my base?
- What is the current pose of the base frame in the map frame?
Tf can operate in a distributed system. This means all the information about the coordinate frames of a robot is available to to all ROS components on any computer in the system.
Tf provides a large set of tools to work with coordinate frames:
- the message notifier passes through messages that can be transformed into a specified frame,
- viewframes allows you to visualize the full tree of coordinate transforms
- the tf_monitor allows you to monitor the transform between frames
- tfwtf helps you track down problems with tf
How do I use tf?
We created a set of tutorials that walk you through using tf, step by step. You can get started on the introduction to tf tutorial. For a complete list of all tf and tf-related tutorials check out the tutorials page.
There are essentially two tasks that an average user would use tf for:
Broadcasting transforms - The TransformBroadcaster sends out the relative pose of coordinate frames to the rest of the system. A system can have many broadcasters that each provide information about a different part of the robot. For a beginner level discussion on how to broadcast transforms, check out the writing a tf broadcaster tutorial (Python) (C++).
Listening for transforms - The TransformListener receives and buffers all coordinate frames that are broadcasted in the system, and allows you to query for specific transforms between frames. For a beginner level discussion on how to listen to and work with transforms, check out the check out the writing a tf listener tutorial (Python) (C++).
Once you are finished with the basic tutorials, you can move on to learn about tf and time. The tf and time tutorial (Python) (C++) teaches the basic principles of tf and time. The advanced tutorial about tf and time (Python) (C++) teaches the principles of time traveling with tf.
tf Visualization and Debugging Tools
The tf package provides a variety of tools that will let you monitor and debug what is going on inside tf. There are two sets of tools.
tf message types
Tf can deal with messages describing poses, vectors, points, etc. You can find a complete list of messages here.
tf Visualization
The rviz visualizer provides a way to visualize the tree structure. It is part of the Visualization package. For more information on using rviz, read the User's Manual. Also have a look at a screenshot of the TF tree.
tf and Threading
A tf::TransformListener class is continuously listening to tree update information. Any blocking call can severely disrupt the flow of information to the listener. A transform listener, by default, spins its own thread. This particularly helps with calls to functions like waitForTransform which can block callbacks while it is waiting to hear back from tf.
The API for tf::Transformer tf::TransformListener and tf::TransformSender are all threadsafe
tf::Transformer::waitForTransform requires a dedicated listening thread (provided by default by tf::TransformListener)
Frequently Asked Questions
Can be found on tf/FAQ
