[ros-users] urdf meshes generate "No root link found" error

[Wim Meeussen]

Grace,

You forgot to close the 'resource' element at line 3 of your xml file:

<resource type ="stl_meshes" location = "home/yglee/ros/ros/HUMAN/stl_files">

This caused the rest of your xml file to be hidden inside the resource
element. I'll make the error message of the parser more informative in
case the tree is empty.

Wim




On Mon, Jul 12, 2010 at 9:08 AM, Yeon Grace Lee <yeongrace.lee at gmail.com> wrote:
> Hi,
>
> I am currently writing an urdf file for a human model. The human model ran
> fine in rviz when I used geometric shapes for links. Recently I have
> uploaded STL files and changed the link geometry to that of a mesh. This has
> generated a "No root link found" error even though nothing has been changed
> in parent-child relationships in joints and names of links and joints have
> stayed constant. I have also opened up my STL files in blender and they all
> have no problem opening and displaying the models (they have been exported
> from Maya). I'm not quite sure what I am missing in my urdf or my
> state_publisher file. It may be something simple that I am not aware of. I
> have attached the two files (model.xml and state_publisher.cpp). The error
> generated is below:
>
> yglee at yglee-laptop:~/ros/ros/HUMAN$ roslaunch HUMAN launch_file.launch
> ... logging to
> /home/yglee/.ros/log/7c565b12-8dce-11df-b146-00236c960005/roslaunch-yglee-laptop-2123.log
>
> started roslaunch server http://yglee-laptop:42319/
>
> SUMMARY
> ========
>
> PARAMETERS
>  * /robot_description
>
> NODES
>   /
>     robot_state_publisher (robot_state_publisher/state_publisher)
>     state_publisher (HUMAN/state_publisher)
>
> WARNING: IP address 127.0.1.1 for local hostname 'yglee-laptop' does not
> appear to match
> any local IP address (127.0.0.1,192.168.2.153). Your ROS nodes may fail to
> communicate.
>
> Please use ROS_IP to set the correct IP address to use.
> starting new master (master configured for auto start)
> process[master]: started with pid [2137]
> ROS_MASTER_URI=http://yglee-laptop:11311/
>
> setting /run_id to 7c565b12-8dce-11df-b146-00236c960005
> process[rosout-1]: started with pid [2148]
> started core service [/rosout]
> process[robot_state_publisher-2]: started with pid [2161]
> process[state_publisher-3]: started with pid [2163]
> [ERROR] 1278950383.696006000: No root link found. The robot xml is not a
> valid tree.
> [ERROR] 1278950383.696138000: failed to find root link
> [ERROR] 1278950383.696279000: Could not generate robot model
> [ERROR] 1278950383.696612000: Failed to extract kdl tree from xml robot
> description
> [robot_state_publisher-2] process has died [pid 2161, exit code 255].
> log files:
> /home/yglee/.ros/log/7c565b12-8dce-11df-b146-00236c960005/robot_state_publisher-2*.log
> ^C[state_publisher-3] killing on exit
> [rosout-1] killing on exit
> [master] killing on exit
> exiting...
> shutting down processing monitor...
> ... shutting down processing monitor complete
> done
>
>
> Thank you in advance for your help.
>
> Grace L.
>
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>



-- 
--
Wim Meeussen
Willow Garage Inc.
<http://www.willowgarage.com)