Where is the file I was looking at before I logged in?

Hi,
I used Google to find a CAD model.
GrabCAD appeared with a great model, but it said I needed to log in.
Upon doing so the model I was looking at dissappeared and there was no search field to find it again!
And pressing the back button takes me to the page with the model, but I am once again logged out!
So, how are we supposed to use this site? :)