Objects no longer rendering after upgrade

It has been a long time since I have done any Unity, so I wanted to upgrade my prototype from Unity 3 to 5. After upgrading my custom prefabs no longer seem to to visible–I can see their outline in the scene view, but nothing in the game view.

The default layer is visible, and pressing ‘F’ doesn’t make it appear. Since it has been a long time and there have been a lot of changes since Unity 3, I am not sure where to start. I intend to go over the tutorials again, but it would be good to get my old project running first.

First thing I would check is mesh import scale. It’s possible they are loading in at like 0.01 scale, making them effectively invisible. If the bounding volumes were imported correctly, it would not zoom in enough to see the models.

Have solved the problem. When I upgraded my project I no longer had Blender installed. I have since installed Blender and then right-clicked on each prefab and clicked Reimport.