Problem importing obj from probuilder

Hi!

-So I finish my model using probuilder tools.
-I proceed to press the export button on the PB window.
-there are different options I choose obj.
-I open a new scene, install probuilder, and import the object.

But the importet obj doesn't have collisions, and it seems like its simpler than a cube.





-So I add a mesh collider to check if it does the trick but nothing happens other objects just pass through the imported .obj

-I also tried exporting this as an asset

I have a friend working on a game on another computer /scene so my objective is to send it to him so he can import it to the project.

thanks