Added some text to the docs on the zernike distortions.

doc/source/distortions.rst

@@ -49,4 +49,37 @@ turns out to be useful at the C-level during tracing. I.e.::
     dZdY = grad[...,1]
     Z = grad[...,2]
 
-    
+Zernike Polymonial Distortions
+------------------------------
+
+More general distortions can be applied using the :py:class:`raypier.distortions.ZernikeSeries` class.
+
+As previously, instances of this object are passed to a :py:class:`raypier.faces.DistortionFace` , along
+with the base-surface to which the distortion is to be applied.
+
+.. py:class:: ZernikeSeries(unit_radius=10.0, coefficients=[])
+    :canonical: raypier.distortions.ZernikeSeries
+
+    Describes a general distortion defined in terms of Zernike polynomials. 
+    The ANSI single-index (J) notation is used to identify coefficients.
+
+    A recursive algorithm is used for evaluation of the function with caching
+    for efficient evaluation where many non-zero coefficients exist.
+
+    Both the given parameters are traits on this object and updates to either 
+    one will automatically update the internal state of the object (and trigger
+    re-tracing of the model).
+
+    :param float unit_radius: Specifies the unit-radius for the Zernike polynomials.
+    :param list coefficients: A sequence of coefficient amplitudes, given a tuples (J, amplitude).
+                            E.g. [(0,0.1),(2,0.3),(7,2.34)]. Any number of coefficients
+                            can be specified.
+
+
+An example of the this class in action can be seen here:
+
+.. literalinclude:: /../../examples/zernike_distortion_example.py
+
+.. image:: images/zernike_distortion_example.png
+
+

examples/zernike_distortion_example.py

@@ -18,18 +18,19 @@
 
 
 shape = CircleShape(radius=10.0)
+
 #f1 = SphericalFace(z_height=0.0, curvature=-25.0)
+
 f1 = PlanarFace(z_height=0.0)
 f2 = PlanarFace(z_height=5.0)
 
-#dist = SimpleTestZernikeJ7(unit_radius=10.0, amplitude=0.01)
-#dist = NullDistortion()
-
 dist = ZernikeSeries(unit_radius=10.0, coefficients=[(i,0.0) for i in range(12)])
 f1 = DistortionFace(base_face=f1, distortion=dist)
 
 
 class Sliders(Constraint):
+    """Make a Constrain object just to give us a more convenient UI for adjusting Zernike coefficients.
+    """
     J0 = Range(-1.0,1.0,0.0)
     J1 = Range(-1.0,1.0,0.0)
     J2 = Range(-1.0,1.0,0.0)