zed multi camera launch bug

Gal · December 29, 2025, 2:54pm

i downloaded the zed-ros2-examples and when trying to run the zed_multi_camera launch i get
ros2 launch zed_multi_camera zed_multi_camera.launch.py \

cam_names:=‘[zed_left,zed_right]’
cam_models:=‘[zed2i,zed2i]’
cam_serials:=‘[35014157,39453324]’
[INFO] [launch]: All log files can be found below /root/.ros/log/2025-12-29-14-29-37-784393-ubuntu3-134
[INFO] [launch]: Default logging verbosity is set to INFO
[INFO] [launch.user]: * Starting Composable node container: /zed_multi/zed_multi_container
[ERROR] [launch]: Caught exception in launch (see debug for traceback): ‘NoneType’ object is not iterable

i tried running it with debug and got

ros2 launch zed_multi_camera zed_multi_camera.launch.py \

cam_names:=‘[zed_left,zed_right]’
cam_models:=‘[zed2i,zed2i]’
cam_serials:=‘[35014157,39453324]’
–debug
[DEBUG] [launch.launch_context]: emitting event synchronously: ‘launch.events.IncludeLaunchDescription’
[INFO] [launch]: All log files can be found below /root/.ros/log/2025-12-29-14-36-28-466291-ubuntu3-143
[INFO] [launch]: Default logging verbosity is set to DEBUG
[DEBUG] [launch]: processing event: ‘<launch.events.include_launch_description.IncludeLaunchDescription object at 0xffff96874610>’
[DEBUG] [launch]: processing event: ‘<launch.events.include_launch_description.IncludeLaunchDescription object at 0xffff96874610>’ ✓ ‘<launch.event_handlers.on_include_launch_description.OnIncludeLaunchDescription object at 0xffff968742b0>’
[INFO] [launch.user]: * Starting Composable node container: /zed_multi/zed_multi_container
Executing <Task finished name=‘Task-2’ coro=<LaunchService._process_one_event() done, defined at /opt/ros/humble/install/lib/python3.8/site-packages/launch/launch_service.py:228> exception=TypeError(“‘NoneType’ object is not iterable”) created at /opt/ros/humble/install/lib/python3.8/site-packages/launch/launch_service.py:318> took 0.310 seconds
[DEBUG] [launch]: An exception was raised in an async action/event
[DEBUG] [launch]: Traceback (most recent call last):
File “/opt/ros/humble/install/lib/python3.8/site-packages/launch/launch_service.py”, line 336, in run_async
raise completed_tasks_exceptions[0]
File “/opt/ros/humble/install/lib/python3.8/site-packages/launch/launch_service.py”, line 230, in _process_one_event
await self.__process_event(next_event)
File “/opt/ros/humble/install/lib/python3.8/site-packages/launch/launch_service.py”, line 250, in __process_event
visit_all_entities_and_collect_futures(entity, self.__context))
File “/opt/ros/humble/install/lib/python3.8/site-packages/launch/utilities/visit_all_entities_and_collect_futures_impl.py”, line 45, in visit_all_entities_and_collect_futures
futures_to_return += visit_all_entities_and_collect_futures(sub_entity, context)
File “/opt/ros/humble/install/lib/python3.8/site-packages/launch/utilities/visit_all_entities_and_collect_futures_impl.py”, line 45, in visit_all_entities_and_collect_futures
futures_to_return += visit_all_entities_and_collect_futures(sub_entity, context)
File “/opt/ros/humble/install/lib/python3.8/site-packages/launch/utilities/visit_all_entities_and_collect_futures_impl.py”, line 45, in visit_all_entities_and_collect_futures
futures_to_return += visit_all_entities_and_collect_futures(sub_entity, context)
[Previous line repeated 2 more times]
File “/opt/ros/humble/install/lib/python3.8/site-packages/launch/utilities/visit_all_entities_and_collect_futures_impl.py”, line 38, in visit_all_entities_and_collect_futures
sub_entities = entity.visit(context)
File “/opt/ros/humble/install/lib/python3.8/site-packages/launch/action.py”, line 108, in visit
return self.execute(context)
File “/opt/ros/humble/install/lib/python3.8/site-packages/launch_ros/actions/composable_node_container.py”, line 83, in execute
for node_object in self.__composable_node_descriptions:
TypeError: ‘NoneType’ object is not iterable

[ERROR] [launch]: Caught exception in launch (see debug for traceback): ‘NoneType’ object is not iterable
[DEBUG] [launch.launch_context]: emitting event: ‘launch.events.Shutdown’
[DEBUG] [launch]: processing event: ‘<launch.events.shutdown.Shutdown object at 0xffff96874280>’
[DEBUG] [launch]: processing event: ‘<launch.events.shutdown.Shutdown object at 0xffff96874280>’ ✓ ‘<launch.event_handlers.on_shutdown.OnShutdown object at 0xffff968744c0>’

might there be a bug in the launch?
this one works correctly
ros2 launch zed_wrapper zed_camera.launch.py
camera_model:=zed2i
container_name:=zed_container
serial_number:=$$SERIAL"; \

Myzhar · December 29, 2025, 4:48pm

Hi @Gal
Welcome to the Stereolabs community.

Please remove the ‘’:

cam_names:=[zed_left,zed_right]
cam_models:=[zed2i,zed2i]

Gal · December 29, 2025, 5:01pm

ros2 launch zed_multi_camera zed_multi_camera.launch.py \

cam_names:=[zed_left,zed_right] \
cam_models:=[zed2i,zed2i] \
cam_serials:=[35014157,39453324] \
--debug

[DEBUG] [launch.launch_context]: emitting event synchronously: ‘launch.events.IncludeLaunchDescription’
[INFO] [launch]: All log files can be found below /root/.ros/log/2025-12-29-16-57-40-795119-ubuntu3-84
[INFO] [launch]: Default logging verbosity is set to DEBUG
[DEBUG] [launch]: processing event: ‘<launch.events.include_launch_description.IncludeLaunchDescription object at 0xffffb29e3520>’
[DEBUG] [launch]: processing event: ‘<launch.events.include_launch_description.IncludeLaunchDescription object at 0xffffb29e3520>’ ✓ ‘<launch.event_handlers.on_include_launch_description.OnIncludeLaunchDescription object at 0xffffb29f6af0>’
[INFO] [launch.user]: * Starting Composable node container: /zed_multi/zed_multi_container
Executing <Task finished name=‘Task-2’ coro=<LaunchService._process_one_event() done, defined at /opt/ros/humble/install/lib/python3.8/site-packages/launch/launch_service.py:228> exception=TypeError(“‘NoneType’ object is not iterable”) created at /opt/ros/humble/install/lib/python3.8/site-packages/launch/launch_service.py:318> took 0.320 seconds
[DEBUG] [launch]: An exception was raised in an async action/event
[DEBUG] [launch]: Traceback (most recent call last):
File “/opt/ros/humble/install/lib/python3.8/site-packages/launch/launch_service.py”, line 336, in run_async
raise completed_tasks_exceptions[0]
File “/opt/ros/humble/install/lib/python3.8/site-packages/launch/launch_service.py”, line 230, in _process_one_event
await self.__process_event(next_event)
File “/opt/ros/humble/install/lib/python3.8/site-packages/launch/launch_service.py”, line 250, in __process_event
visit_all_entities_and_collect_futures(entity, self.__context))
File “/opt/ros/humble/install/lib/python3.8/site-packages/launch/utilities/visit_all_entities_and_collect_futures_impl.py”, line 45, in visit_all_entities_and_collect_futures
futures_to_return += visit_all_entities_and_collect_futures(sub_entity, context)
File “/opt/ros/humble/install/lib/python3.8/site-packages/launch/utilities/visit_all_entities_and_collect_futures_impl.py”, line 45, in visit_all_entities_and_collect_futures
futures_to_return += visit_all_entities_and_collect_futures(sub_entity, context)
File “/opt/ros/humble/install/lib/python3.8/site-packages/launch/utilities/visit_all_entities_and_collect_futures_impl.py”, line 45, in visit_all_entities_and_collect_futures
futures_to_return += visit_all_entities_and_collect_futures(sub_entity, context)
[Previous line repeated 2 more times]
File “/opt/ros/humble/install/lib/python3.8/site-packages/launch/utilities/visit_all_entities_and_collect_futures_impl.py”, line 38, in visit_all_entities_and_collect_futures
sub_entities = entity.visit(context)
File “/opt/ros/humble/install/lib/python3.8/site-packages/launch/action.py”, line 108, in visit
return self.execute(context)
File “/opt/ros/humble/install/lib/python3.8/site-packages/launch_ros/actions/composable_node_container.py”, line 83, in execute
for node_object in self.__composable_node_descriptions:
TypeError: ‘NoneType’ object is not iterable

[ERROR] [launch]: Caught exception in launch (see debug for traceback): ‘NoneType’ object is not iterable
[DEBUG] [launch.launch_context]: emitting event: ‘launch.events.Shutdown’
[DEBUG] [launch]: processing event: ‘<launch.events.shutdown.Shutdown object at 0xffffb29e3160>’
[DEBUG] [launch]: processing event: ‘<launch.events.shutdown.Shutdown object at 0xffffb29e3160>’ ✓ ‘<launch.event_handlers.on_shutdown.OnShutdown object at 0xffffb29e33d0>’

im using these branches
zed-ros2-interfaces branch humble
zed-ros2-wrapper branch humble-v.4.2.5
zed-ros2-examples branch master

Myzhar · December 29, 2025, 5:07pm

You are using uncompatible branches. The versions must be compatible.
If you use the wrapper for the ZED SDK v4.2.5 (which is very old), you must use the versions v4.x of all the other repositories: