GAZEBO doesn't find mesh file in URDF.

edit

In ROS2 I have created a python package called "mars_robot" which simply includes the URDF model of a robot and a "launch" file to start the simulation in Gazebo. This URDF model uses mesh files that are included with code lines like the following:

<mesh filename="package://meshes/base_link.stl" scale="0.001 0.001 0.001"/>

The URDF file is in a folder named "urdf" and mesh files are in a folder named "meshes" . Both are inside the package folders structure. Once I compile the package and asure that urdf an mesh files are in the corresponding folders of the package inside the "install" workspace folder I try to run the launch file but Gazebo is not able to load the mesh files because it doestn't find them. However, if in the lines of code where the mesh files are referenced I replace "package://" with "$(find mars_robot)/" then it works.

<mesh filename="$(find mars_robot)/meshes/base_link.stl" scale="0.001 0.001 0.001"/>

Why the code doesn't work using "package://"?

Thanks in advance for your help.