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Gazebo 9.4.1 won't start via x2go

Hey there!

Short summary of my problem: I have a PC with Ubuntu 18.04. running the LXDE desktop environment. Gazebo 9.4.1. works smoothly. However, I was not able to start it from a remote PC logged in via x2go. In this case, the following error message (nothing else) is printed on the console:.

Error [Param.cc:404] Invalid argument.
Unable to set value [.1 ] for key[near].
Exception [Param.cc:57] SDF ASSERTION                     
Invalid parameter
In function       : Param
Assert expression : this->ValueFromString(_default)
terminate called after throwing an instance of 'sdf::AssertionInternalError'

Background: I am trying to set up a dedicated, powerful development PC for some projects based on ROS/Gazebo with highly complex simulations, to be used by a couple of researchers and students. I installed ros-melodic-desktop-full and was able to run a simple test simulation just fine. To allow concurrent usage of this machine, remote access with x2go is desired. Unfortunately, x2go does not support GNOME, which is the default desktop environment for Ubuntu 18.04. Therefore I installed LXDE (using tasksel), which x2go handles very well. As mentioned i can start Gazebo when logged in directly on this machine (either LXDE or GNOME), but not if logged in remotely.

I would highly appreciate any hint about how to fix this or other ideas on how to set up a remote development machine. Surely I'm not the only one with this kind of problem?

Thank you so much in advance!

Gazebo 9.4.1 won't start via x2go

Hey there!

Short summary of my problem: I have a PC with Ubuntu 18.04. running the LXDE desktop environment. Gazebo 9.4.1. works smoothly. However, I was not able to start it from a remote PC logged in via x2go. In this case, the following error message (nothing else) is printed on the console:.

Error [Param.cc:404] Invalid argument.
Unable to set value [.1 ] for key[near].
Exception [Param.cc:57] SDF ASSERTION                     
Invalid parameter
In function       : Param
Assert expression : this->ValueFromString(_default)
terminate called after throwing an instance of 'sdf::AssertionInternalError'

Background: I am trying to set up a dedicated, powerful development PC for some projects based on ROS/Gazebo with highly complex simulations, to be used by a couple of researchers and students. I installed ros-melodic-desktop-full and was able to run a simple test simulation just fine. To allow concurrent usage of this machine, remote access with x2go is desired. Unfortunately, x2go does not support GNOME, which is the default desktop environment for Ubuntu 18.04. Therefore I installed LXDE (using tasksel), which x2go handles very well. As mentioned i can start Gazebo when logged in directly on this machine (either LXDE or GNOME), but not if logged in remotely.

I would highly appreciate any hint about how to fix this or other ideas on how to set up a remote development machine. Surely I'm not the only one with this kind of problem?

Thank you so much in advance!

UPDATE: I was able to make some progress by editing the file /etc/default/locale and setting everything to en_US.UTF-8. For some reason it didn't like that some were originally set to de_DE.UTF-8 as it seems. Now, I get another error message when lauching gazebo --verbose:

...
[Err] [RenderEngine.cc:740] Unable to create glx visual
[Wrn] [RenderEngine.cc:93] Unable to create X window. Rendering will be disabled
[Wrn] [RenderEngine.cc:293] Cannot initialize render engine since render path type is NONE. Ignore this warning ifrendering has been turned off on purpose.
[Err] [GLWidget.cc:178] GLWidget could not create a scene. This will likely result in a blank screen.
...

From what I found out with Google so far, this could be related to the fact that this PC has 2 ATI graphics cards in it. However I wonder why it had no issues when launched directly on the machine (not via remote login). I will investigate, but of course any pointer is still appreciated.