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!