Periodic

This surface shape is described by the following expression:

where A is the peak to valley height in lens units of the modulation, and the values α and β are the spatial frequencies of the oscillations in the x and y directions, respectively. Note this expression is the sag of a sphere plus the cosine modulation. The sag of the surface is exactly zero at the vertex, and the amplitude is the peak to valley amplitude. The frequencies are measured in inverse lens units.

This surface uses three parameter values, and none of the extra data values.

PARAMETER DEFINITIONS FOR PERIODIC SURFACES

Parameter #	Definition
1	A
2	α
3	β

Next:

• Polynomial