Lighting, Compositing, Setup Guide
July 6th, 2008
For the junction environment I’m just going to share a bit the lighting set up, the passes I’ve used and the way they composite together.
If you want some more information about the passes I use, why and how they are composited togther, check out my compositing guides on my site here: Part 01, Part 02.
As a start, here is the compositing tree in XSI’s FxTree.
In the top left you can see the beauty pass, then following down from it the different ID passes and the colour corrections using those mattes. Then on the right there is mostly the depth, the background and the ambient occlusion with varies grading.
In the (bottom) left area there is some extras like glows from the street lights and the sky.
On the next series of images the node which is shown in the image is highlighted on the tree. Click on any of them to view a larger version.
The first image is the beauty pass straight from the render. The dodgy pixels around the edge of the sky/buildings, is the alpha channel that has been un-premultiplied and gets that sorted back again in the ‘over’ node when the background is added.
There is no GI or final gather etc. in the renders. The beauty pass is made up of infinite fill lights, and additional rim or specular-only lights which only affect specific objects too add some highlight and shape to some of the objects.
For instance the barriers on the islands in the middle, the church at the back, the traffic lights, and the bits on the near right side - they all have some additional lights, some just spec, some diffuse as well.
The following are the ID passes (at the moment) that are used to grade certain areas of the image, mostly just on the beauty render, but they can potentially be used at any point in the tree.
And the depth pass, this one is aliased as it is used in the comp, but also I render a version with no AA, which may also be a different range of distance from black to white, and at a very high resolution for the depth of field if there is some.
Ambient Occlusion which is then tinted and graded slightly (changing of the levels)
Using a multiply node, the AO and the beauty pass come together.
This is the same depth path, with a change of levels, and graded/tinted to be used as haze/fog type stuff.
The haze added!
The background, which is from a photo I have taken, but also painted up a bit, the building on the left is only still there as you cannot see it 
The passes is merged over the background, notice that the dodgy alpha edges have gone now and we don’t get any artefacts, dark alpha edges around the buildings because of this process.
Grading, grain, and some nice glowy bits brought in from other passes are added and we end up with the final image.
Not too in-depth but I hope it is interesting to see some of the passes and a few techniques.
Cheers!
