I am trying to get a depth map of my imported model for which I found out this tutorial. So far here is the picture of my work. As you guys can see there is no preview in the backdrop or the nodes of the node editor, I read in a couple of places to render my model to make these preview appear but that didn't work for me too.
The updated image to find the depth map using mist. Mist is checked in the
render layer settings also.