# Behavior Trees for ROS2 **URL:** https://get-help.theconstruct.ai/c/course-support/behavior-trees-for-ros2/120.md [Latest](https://get-help.theconstruct.ai/latest.md) · [Categories](https://get-help.theconstruct.ai/categories.md) · [Tags](https://get-help.theconstruct.ai/tags.md) --- ## [About the Behavior Trees for ROS2 category](https://get-help.theconstruct.ai/t/about-the-behavior-trees-for-ros2-category/21538)
**Author:** [@system](https://get-help.theconstruct.ai/u/system)\ **Replies:** 0
--- ## [\[Bug\] Error in test5](https://get-help.theconstruct.ai/t/bug-error-in-test5/41273)
**Author:** [@eblady](https://get-help.theconstruct.ai/u/eblady)\ **Replies:** 1\ **Last updated:** [June 8, 2026, 9:41am UTC](https://get-help.theconstruct.ai/t/bug-error-in-test5/41273 "2026-06-08T09:41:09Z")
This is an error report. Screenshot of the error Error details Hi, This error appears when testing the test5 program of BTs. In addition, it is not clear in the course how to run the Groot application. --- ## [\[Bug\] Error in Behavior Trees ROS2, Unit1](https://get-help.theconstruct.ai/t/bug-error-in-behavior-trees-ros2-unit1/40841)
**Author:** [@eblady](https://get-help.theconstruct.ai/u/eblady)\ **Replies:** 2\ **Last updated:** [April 29, 2026, 4:28pm UTC](https://get-help.theconstruct.ai/t/bug-error-in-behavior-trees-ros2-unit1/40841 "2026-04-29T16:28:09Z")
This is an error report. Screenshot of the error Error details Hi, In the course Behavior Trees for ROS2, Unit 1 (INtro) There is an error: ./test\_unit1: symbol lookup error: ./test\_unit1: undefined symbol: \_ZN2… --- ## [Behaviortree\_ros2 stuck compiling for 50 minutes](https://get-help.theconstruct.ai/t/behaviortree-ros2-stuck-compiling-for-50-minutes/40013)
**Author:** [@mrah](https://get-help.theconstruct.ai/u/mrah)\ **Replies:** 1\ **Last updated:** [February 23, 2026, 12:46pm UTC](https://get-help.theconstruct.ai/t/behaviortree-ros2-stuck-compiling-for-50-minutes/40013 "2026-02-23T12:46:49Z")
Hi, the file in the title has been stuck at 88% for 50+ minutes and I am unable to continue onto rest of the course. --- ## [Behavior Trees for ROS2](https://get-help.theconstruct.ai/t/behavior-trees-for-ros2/37466)
**Author:** [@engenharia](https://get-help.theconstruct.ai/u/engenharia)\ **Replies:** 1\ **Last updated:** [August 11, 2025, 12:30pm UTC](https://get-help.theconstruct.ai/t/behavior-trees-for-ros2/37466 "2025-08-11T12:30:59Z")
O diretório “scr” está vazio. No notebook diz o seguinte: “You can find the below C++ script in the following path: /home/user/ros2\_ws/src/bt\_course\_files/BehaviorTree.CPP/course\_bt”. --- ## [\[Bug\] Error in unit 2 of Behavior Tree Course](https://get-help.theconstruct.ai/t/bug-error-in-unit-2-of-behavior-tree-course/37048)
**Author:** [@idrg](https://get-help.theconstruct.ai/u/idrg)\ **Replies:** 1\ **Last updated:** [July 9, 2025, 9:09am UTC](https://get-help.theconstruct.ai/t/bug-error-in-unit-2-of-behavior-tree-course/37048 "2025-07-09T09:09:44Z")
This is an error report. Screenshot of the error Error details Following the instructions gives this error. --- ## [Test\_unit4 execution error](https://get-help.theconstruct.ai/t/test-unit4-execution-error/35733)
**Author:** [@kjkaveny](https://get-help.theconstruct.ai/u/kjkaveny)\ **Replies:** 5\ **Last updated:** [April 10, 2025, 4:25pm UTC](https://get-help.theconstruct.ai/t/test-unit4-execution-error/35733 "2025-04-10T16:25:20Z")
I’m getting this error after updating test\_unit4.cpp lines 214-225 match the solution: user:~/ros2\_ws/build/behaviortree\_ros2$ ./test\_unit4 terminate called after throwing an instance of ‘BT::RuntimeError’ what(): E… --- ## [What does "the Factory" mean in this context?](https://get-help.theconstruct.ai/t/what-does-the-factory-mean-in-this-context/35726)
**Author:** [@kjkaveny](https://get-help.theconstruct.ai/u/kjkaveny)\ **Replies:** 1\ **Last updated:** [April 9, 2025, 8:09am UTC](https://get-help.theconstruct.ai/t/what-does-the-factory-mean-in-this-context/35726 "2025-04-09T08:09:04Z")
A single instance of each node type must be registered with the Factory. This can be done either directly in the C++ code, with the help of static linking, or at runtime, when new nodes are loaded from a collection of p… --- ## [\[Bug\] Unit3 Groot monitor does not connect](https://get-help.theconstruct.ai/t/bug-unit3-groot-monitor-does-not-connect/34429)
**Author:** [@fgenestcvdl](https://get-help.theconstruct.ai/u/fgenestcvdl)\ **Replies:** 5\ **Last updated:** [January 20, 2025, 7:38pm UTC](https://get-help.theconstruct.ai/t/bug-unit3-groot-monitor-does-not-connect/34429 "2025-01-20T19:38:46Z")
This is an error report. Screenshot of the error Error details Error was not able to connect to tcp//localhost:1666 --- ## [ReadingLaser code interpretation](https://get-help.theconstruct.ai/t/readinglaser-code-interpretation/34449)
**Author:** [@fgenestcvdl](https://get-help.theconstruct.ai/u/fgenestcvdl)\ **Replies:** 2\ **Last updated:** [January 20, 2025, 2:57pm UTC](https://get-help.theconstruct.ai/t/readinglaser-code-interpretation/34449 "2025-01-20T14:57:03Z")
what is the intent of this loop ? // 200 readings, from right to left, from -57 to 57 degress // calculate new velocity cmd float min = 10; float current; for (int i = 0; i \< 200; i++) { current = data1; if (current… --- ## [\[Bug\] why am i take this error](https://get-help.theconstruct.ai/t/bug-why-am-i-take-this-error/34155)
**Author:** [@mirackurtak7](https://get-help.theconstruct.ai/u/mirackurtak7)\ **Replies:** 1\ **Last updated:** [December 31, 2024, 9:00am UTC](https://get-help.theconstruct.ai/t/bug-why-am-i-take-this-error/34155 "2024-12-31T09:00:54Z")
This is an error report. Screenshot of the error Error details i couldnt solve it please fix it. --- ## [\[Bug\] Simulation not working in Behavior Tree Course](https://get-help.theconstruct.ai/t/bug-simulation-not-working-in-behavior-tree-course/34124)
**Author:** [@rutweek.joshi](https://get-help.theconstruct.ai/u/rutweek.joshi)\ **Replies:** 2\ **Last updated:** [December 30, 2024, 8:54am UTC](https://get-help.theconstruct.ai/t/bug-simulation-not-working-in-behavior-tree-course/34124 "2024-12-30T08:54:27Z")
This is an error report. Screenshot of the error Error details Simulation is not starting for this course. --- ## [\[Bug\] For U4\_ex3 execution error](https://get-help.theconstruct.ai/t/bug-for-u4-ex3-execution-error/33822)
**Author:** [@yuyueqi1993](https://get-help.theconstruct.ai/u/yuyueqi1993)\ **Replies:** 0\ **Last updated:** [December 5, 2024, 7:23pm UTC](https://get-help.theconstruct.ai/t/bug-for-u4-ex3-execution-error/33822 "2024-12-05T19:23:50Z")
This is an error report. Screenshot of the error Error details Just running the given code and shows halt called and a different output showed up --- ## [\[Bug\] notebook error](https://get-help.theconstruct.ai/t/bug-notebook-error/33267)
**Author:** [@alsghd3](https://get-help.theconstruct.ai/u/alsghd3)\ **Replies:** 1\ **Last updated:** [October 29, 2024, 11:20am UTC](https://get-help.theconstruct.ai/t/bug-notebook-error/33267 "2024-10-29T11:20:09Z")
This is an error report. Screenshot of the error Error details i don't know why this error message appear when loading explain description --- ## [\[Bug\] bt\_interfacesConfig.cmake](https://get-help.theconstruct.ai/t/bug-bt-interfacesconfig-cmake/32680)
**Author:** [@Adil-Shahryar](https://get-help.theconstruct.ai/u/Adil-Shahryar)\ **Replies:** 2\ **Last updated:** [October 1, 2024, 1:25pm UTC](https://get-help.theconstruct.ai/t/bug-bt-interfacesconfig-cmake/32680 "2024-10-01T13:25:43Z")
This is an error report. Screenshot of the error Error details I have completed this course and solved problems, but when I go to practice on my PC, there is a problem with the bt\_interfacesConfig.cmake file. pleas… --- ## [Behaviortree\_ros2 package will not compile](https://get-help.theconstruct.ai/t/behaviortree-ros2-package-will-not-compile/31681)
**Author:** [@LenaPanda](https://get-help.theconstruct.ai/u/LenaPanda)\ **Replies:** 5\ **Last updated:** [August 8, 2024, 1:01pm UTC](https://get-help.theconstruct.ai/t/behaviortree-ros2-package-will-not-compile/31681 "2024-08-08T13:01:07Z")
I cannot get the package to compile. It always stops somewhere between 65 and 95 % of compiling, even after 20 minutes. I already made a new account to start all over. When it still did not work I also deleted install, l… --- ## [Bt\_interface not find in CmakeList humble distro](https://get-help.theconstruct.ai/t/bt-interface-not-find-in-cmakelist-humble-distro/31499)
**Author:** [@duygiangtemp](https://get-help.theconstruct.ai/u/duygiangtemp)\ **Replies:** 4\ **Last updated:** [August 1, 2024, 7:34am UTC](https://get-help.theconstruct.ai/t/bt-interface-not-find-in-cmakelist-humble-distro/31499 "2024-08-01T07:34:52Z")
I get error when build project with bt\_behavior CMake Error at CMakeLists.txt:23 (find\_package): By not providing "Findbt\_interfaces.cmake" in CMAKE\_MODULE\_PATH this project has asked CMake to find a package configu… --- ## [\[Bug\] Process Has Died](https://get-help.theconstruct.ai/t/bug-process-has-died/28791)
**Author:** [@oza.param1](https://get-help.theconstruct.ai/u/oza.param1)\ **Replies:** 1\ **Last updated:** [February 8, 2024, 10:51am UTC](https://get-help.theconstruct.ai/t/bug-process-has-died/28791 "2024-02-08T10:51:36Z")
This is an error report. Screenshot of the error Error details the simulation is not launching --- ## [Error with building in Behavior Tree](https://get-help.theconstruct.ai/t/error-with-building-in-behavior-tree/28769)
**Author:** [@oza.param1](https://get-help.theconstruct.ai/u/oza.param1)\ **Replies:** 1\ **Last updated:** [February 7, 2024, 8:52am UTC](https://get-help.theconstruct.ai/t/error-with-building-in-behavior-tree/28769 "2024-02-07T08:52:17Z")
Hi, i am unable to build the package user:~/ros2\_ws$ colcon build \[0.500s\] WARNING:colcon.colcon\_core.package\_selection:Some selected packages are already built in oneor more underlay workspaces: ‘behaviortree\_cpp\_v3’… --- ## [Unit 3 : Behaviour trees Groot](https://get-help.theconstruct.ai/t/unit-3-behaviour-trees-groot/28357)
**Author:** [@muhammadjunaid](https://get-help.theconstruct.ai/u/muhammadjunaid)\ **Replies:** 0\ **Last updated:** [January 12, 2024, 11:40am UTC](https://get-help.theconstruct.ai/t/unit-3-behaviour-trees-groot/28357 "2024-01-12T11:40:09Z")
In unit 3, in heading " 3.7 Remapping Ports Between Trees and SubTrees" , it asks to open groot but does not explain in details the location of .fbl files : Can you please guide me how to locate them ? Best , M… --- ## [Gazebo simulation not working correctly](https://get-help.theconstruct.ai/t/gazebo-simulation-not-working-correctly/28325)
**Author:** [@muhammadjunaid](https://get-help.theconstruct.ai/u/muhammadjunaid)\ **Replies:** 1\ **Last updated:** [January 10, 2024, 12:06pm UTC](https://get-help.theconstruct.ai/t/gazebo-simulation-not-working-correctly/28325 "2024-01-10T12:06:57Z")
Hi ! I hope you are doing well. I am unable to use Gazebo simulation on the workspace. I am getting this error : Can you please help me resolve it. Best regards, Muhammad Junaid --- ## [Hardcoding values on a Behaviour Tree](https://get-help.theconstruct.ai/t/hardcoding-values-on-a-behaviour-tree/25487)
**Author:** [@estebanatwork](https://get-help.theconstruct.ai/u/estebanatwork)\ **Replies:** 1\ **Last updated:** [July 25, 2023, 11:09am UTC](https://get-help.theconstruct.ai/t/hardcoding-values-on-a-behaviour-tree/25487 "2023-07-25T11:09:04Z")
Hi everyone, Do you know if its possible to hardcode values on a Behaviour Tree? I would like to specify a pose directly instead of using {goal} in \ for example. I tried things like: \ **Author:** [@nullbyte91](https://get-help.theconstruct.ai/u/nullbyte91)\ **Replies:** 1\ **Last updated:** [April 18, 2023, 5:29am UTC](https://get-help.theconstruct.ai/t/no-source-code-available-as-per-the-notebook-instruction/23844 "2023-04-18T05:29:01Z") Hi Team, I don’t see any source code file under the /home/user/ros2\_ws/src/ folder. --- ## [Could you reset my course progress](https://get-help.theconstruct.ai/t/could-you-reset-my-course-progress/23108)
**Author:** [@gstoettnerjo](https://get-help.theconstruct.ai/u/gstoettnerjo)\ **Replies:** 7\ **Last updated:** [March 17, 2023, 5:29am UTC](https://get-help.theconstruct.ai/t/could-you-reset-my-course-progress/23108 "2023-03-17T05:29:17Z")
I can not proceed anymore in the behoviour tree course. I already tried to delete and build again the whole wrokspace several times but I still get all kind of weird errors. If you could reset the whole progress I could … --- ## [Nav2 behavior trees nodes' status](https://get-help.theconstruct.ai/t/nav2-behavior-trees-nodes-status/21614)
**Author:** [@lfernandez](https://get-help.theconstruct.ai/u/lfernandez)\ **Replies:** 2\ **Last updated:** [January 16, 2023, 8:17am UTC](https://get-help.theconstruct.ai/t/nav2-behavior-trees-nodes-status/21614 "2023-01-16T08:17:03Z")
Hi everyone In order to check the status of the Nav2 behavior trees used by the bt\_navigator node, is necessary to use the BehaviorTree.CPP library or is there another more straighforward way? Thanks in advance!