I have a problem with course.
after a while you need to execute the following command:
rosrun rviz rviz
after this another window is opened and you need to add a robot and a laserscan.
after i add the laserscan i dont get the wall that i need, in matter of fact i cant even select a topic.
What can i do about this?
In the simulation check whether your robot is facing the wall or not. If its not standing facing the wall, use teleop twist keyboard to move your robot. Once its facing the wall you will be able to see the laser scan on rviz.
Can you post here some screenshots of the full rviz?
For sure you have to have the laser scan topic because that is provided by the simulated robot. Hence, you have to select it in the topic of the LaserScan display of rviz.