Apple Shake 4 - Manual (Page 451)

16
451
16
Compositing With Layer Nodes
Layer nodes form the foundation for compositing two or
more images together in Shake. This chapter covers the
basic Shake compositing nodes—how they work, and
how to use them.
Layering Node Essentials
The Shake compositing nodes are located in the Layer Tool tab.
There are three types of layering nodes:
• Atomic nodes: Atomic nodes (Over, IAdd, Atop, and so on) do one thing—combine
two images according to a fixed mathematical algorithm. (Hence the term atomic:
they apply a single, elemental operation to a pair of images.) They are useful for
command-line compositing, scripting, and are also convenient for the Node View in
that you can quickly see which type of operation is occurring.
• More flexible nodes: The second node type are the more flexible MultiLayer,
MultiPlane, and Select nodes. MultiLayer allows you to duplicate most of the atomic
nodes (with the exception of the AddMix, AddText, Interlace, and KeyMix nodes). These
nodes have the additional benefit of allowing unlimited inputs to the node.
• LayerX node: The third category is the unique node LayerX, which allows you to enter
your own compositing math.
Before getting into the layer nodes in more detail, here are some important rules to
keep in mind when compositing in Shake.
Don’t Mask Layer Nodes
The side-input masks for layer nodes should not be used, as they behave counter-
intuitively and will not produce the result you might expect. If you want to mask a
layering node, mask the input nodes, or use the KeyMix node.
Remember the Rules of Premultiplication
There are two unbreakable rules that you must always follow when creating a
composition in Shake: