Controlling shading on coordinate-based geometry
Syntax: NormalInterpolator
 
- A NormalInterpolator node
describes a normal set
	- keys - key fractions
	- values  - key normal lists (X,Y,Z lists)
	- Interpolates lists of normals, similar to the
	CoordinateInterpolator
 
- NormalInterpolator {
    key [ 0.0, . . . ]
    keyValue [ 0.0 1.0 1.0, . . . ]
}
 
 
- Typically route into a Normal node's
set_vector input