I am trying to use this tutorial to make an FPS style camera in babylon: https://doc.babylonjs.com/divingDeeper/cameras/camera_collisions

I am exporting from blender and using the blender2babylon addon to export my scene.

One of the steps in the FPS camera tutorial says I have to apply collisions to specific meshes in my scene. In the examples, these meshes were made within babylon and hence can be accessed easily. How do I turn on collisions for meshes that were made in blender and exported as part of .babylon files? In general, how do I access and alter information of meshes exported in .babylon files using javascript?