gazebo levels Gazebo levels Demo run gz with levels1gz sim levels.sdf --levels 1 2gz topic -t "/model/vehicle_blue/cmd_vel" -m gz.msgs.Twist -p "linear: {x: 4.0}" gz topic -t "/model/vehicle_red/cmd_vel" -m gz.msgs.Twist -p "linear: {x: 2.0}" Download code Reference gazebo tutorial levels tunnel world with levels