How to use <uri> path under <geometry> <mesh> in ignition gazebo?

edit

I tried to include some stl-files in a sdf-file using a path in the uri element http://sdformat.org/spec?ver=1.4&elem...)

After starting with ign gazebo model.sdf I receive the Error:

[GUI] [Err] [MeshDescriptor.cc:56] Mesh manager can't find mesh named [model://path/to/model.stl] [GUI] [Err] [OgreMeshFactory.cc:423] Cannot load null mesh

I don't know if the link to my folder is correct.

Anyone facing similar problems?

Thanks for any help or ideas.