Game Development Reference
Now let's adjust the Take Matte From Layer drop down to select
the fractal fi re layer. Change the Use For Matte drop down to
use the luminance of the fractal fi re to create the alpha channel
(matte) of the current layer.
The results seen in Fig. 5.62 resemble what would be created
by making a luma matte with these two layers. Notice that these
layers are not next to each other in the layer stacking order in
the Timeline panel. And, it doesn't have to end here. We could
use the green channel, or the saturation, or a whole host of
properties from our second layer to create a matte on the cur-
rent layer. Remember that if you're going to use effects to con-
trol the alpha channel with the Set Matte effect (as I've done
here with the Advanced Lightning and Fractal Noise effects),
then you'll need to precompose the layers that they are applied
to fi rst.
Figure 5.62 Using the luminance
of the fractal fi re layer as the
alpha channel of the lava layer.
The Shift Channels Effect
The Shift Channels effect seems like another weird channel
effect without any utility. But I actually have an interesting exam-
ple, using one of the 3D Channel effects that we looked at back in
Chapter 2. The purpose of the Shift Channels effect is to take the
channel data from an effect and use it in other channels on the
same layer. This is similar to the Set Channels effect, only we're
only allowed to use the attributes of the current layer.
Open the Shift Channels.aep project. This contains the famil-
iar 3D garage scene we've been using as an example in this topic.