The Shake comp.

1) File in the ambDiffPass. With this still selected create a layer => iMult. File in the ambEnvPass and connect it the background input of the iMult.

This multiplies the diffuse by the ambient environment. Introducing colouring and shading in areas where the surface would be lit by the surrounding environment. You can use the percent attribute to control the amount or strength of the ambient environment.

Now, on to the channel lighting technique. Here we will disassemble a simple 3 point light setup and then combine this with our ambOcc to get our final lighting setup.

In this example I have used red as my key light, green as my fill and blue as my rim/kicker light.

2) File in the rgbPass, each channel has a different directional light stored in it. For example the red channel has the key light :

3) Create an image=> color node (this will control the colour and intensity of your light) with this selected create a layer=> SwitchMatte. In the Switch Matte�s parameters set the matte channel to R for red. This multiplies the colour node and restricts it to the areas which are illuminated by the key light. Rename the colour node �keyColor� and set its colour by file-in-ing the BGpass and sampling the colour of the top of the plate in the viewer.

4) Now repeat the previous steps with the fill and rim light. Using reorders set to �ggga� and �bbba� respectively.

5) These separate branches need to be combined together to do this use iAdd. These passes will be added to emulate the additive nature of light in a 3d rendering pipeline!

6) Now iAdd the ambientEnv/diffuse colour comp from step 2

Now we will add our shadow element using a keyMix which will allow us to set shadow colour and shadow strength/opacity.

7) File-in the shadow Pass. With the last of your iAdd nodes selected create a color=>compress node and rename it shadowCompress. Reselect the iAdd node and shift+LMB to branch a layer=> keyMix node. Connect the iAdd to the background input, the shadowCompress to the foreground input and the shadowPass to the key input of the keyMix.

8) Open the parameters for the shadowCompress node and set the high color attribute to the value you want for your shadow:

9) File in the ambOcc pass. With the keyMix from the last step selected, create an iMult and connect the ambOccPass into the background input.

At this stage we have a functioning lighting rig. The three iAdd nodes can be used to control the intensity of the three lights. The shadowCompress and the keyMix percentage can be used to control the colour and intensity of the shadow pass. Finally the percentage attribute of the iMult can be used to tune the amount of occlusion.