You can use the “scale” tag in the mesh to scale it down at the correct size.
Although Its strange because it the simulation in git should be the same as the one in RootIgniteaccademy, which you can see it works in the page. Do “roscd duckietown_description” and that package should work fine.
Thank you for your reply but ı am trying to do it in my own computer. Because of this, ı am getting this problem. I could not understand how to change the scale. There is a scale tag for each mesh in the xacro file, but not for base.dae like below.