Add catkin workspace to Ignition path (Trouble with launching)

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Is there a way to add my catkin workspace to my ignition resource path? I have a launch file in a package that loads an ignition world, but when I try to spawn robots that are in a different package I run into relative path issues.

<env name="IGN_GAZEBO_RESOURCE_PATH" value="$(find sim_buildingblocks)/models"/>

is in my launch file, and is able to load models from sim_buildingblocks. However if I try to spawn a robot from the same package it can find the model file but not the meshes. If I link the mesh as shown below

      <mesh>
        <scale>1 1 1</scale>
        <uri>model://CERBERUS01/meshes/drive.dae</uri>
      </mesh>

It will work

      <mesh>
        <scale>1 1 1</scale>
        <uri>model://meshes/drive.dae</uri>
      </mesh>

will not work.

I also have other robot descriptions that are not in the sim_buildingblocks/models folder. How do I add those to the resource path without overwriting the previous one?