How to single out parts of a rendering?

[icapture]

Hey guys,

So I was watching this video the other day (starts at 1:38 - I used a link that starts the video automatically at that point, but it doesn't seem to work with this forum.)

And in it he drags and drops a ".TGA File" onto Photoshop and it magically converts all the different components of his scene (lamp, wall, curtain, bed, ect.) into flat unique colors. That way he is able to select "bed" simply by selection "color range" and clicking where the bed is.

This is great for changing lighting in specific areas. I am also curious as to the possibilities these .TGA files create.

Can someone enlighten me on how something like this is created? The creator of the video uses 3D max to create the model, and Vray to render it, but I don't think it matters since he is dropping these files into Photoshop.

Here is a screen capture of what I am talking about:

[Pixero]

I don't know what renderer you use but with Thea you can render out a material ID pass and a object ID pass. They have random colors for every material/object which makes it easy to select in Photoshop.