Does anyone know where to find that tutorial that tells you how to ‘superimpose’ objects onto an image in Blender? It was very useful and told you how to render objects in the photo that you wanted to appear in front of the one you’re modelling.
Thanks.
I don’t know about that tutorial. But if I wanted an object in a photo show up in front of the rendered object I’d built it in 3D and set the material’s “env” option. That way the background (photo) becomes visible in that place. Did you mean something like that?
Lets go! I believe it is this what you want.
To place an imagem in front of you scene, you have to use the sequence editor. Quick explanation ahead.
1 Go to the sequence editor window
2 “Shift+A>Images” locate the image you are going to use in the foreground.
Note that this image must have an alpha data. My sugestion is: make a selection around the object you want to show and save the image as .tga with RLE compression on.
3 “Shift+A>Scene” and select the scene you want to show in the background.
4 Select the scene strip, them select the image strip and “Shift+A>Alpha Over”. Place the Alpha Over strip over the other two strips.
Important: You must select the strips in the correct order. If you select in a different order you will get an undesirable effect (in this case) 
5 Place the background image as an world texture
Note: take a look in the map to options
6 Select the option “do sequence” bellow the Anim buttom in F10 menu
7 Render
Voilá! you now have and image with 3 layers: The girl (image w/ alpha), the monkey (3d object in the scene) and the volcano (world texture)
All of them can be animated. The girl: use a image sequence and select the hole sequence in the “shift+A” menu. The monkey: well, there are several ways to do it. The volcano: animated texture (image sequence or movie file)
Hope it helps!
I think the second post has what I needed, but I’d love that whole tut… but thanks gudi3D, you’ve just shown me something cool and useful! 
Make a tutorial and post it!