Node Description & Purpose:
The Complement family of nodes takes the Input value and outputs that value subtracted from one:
Output = 1 minus Input
For colours the calculation is done on a component-wise basis, for example:
Output.red = 1 minus Input.red
Output.green = 1 minus Input.green
Output.blue = 1 minus Input.blue
These nodes are most useful when you are dealing with input values which go from 0 to 1. They can be useful for giving the effect of flipping or inverting a value, for example an input of 0.9 would become 0.1. If you were creating an effect using alpha blending you could use the Complement node to flip an alpha value from almost opaque to nearly transparent.
Node Type: Function
These nodes have no other settings apart from the Input node.
A single object or device in the node network which generates or modifies data and may accept input data or create output data or both, depending on its function. Nodes usually have their own settings which control the data they create or how they modify data passing through them. Nodes are connected together in a network to perform work in a network-based user interface. In Terragen 2 nodes are connected together to describe a scene.