### Description

#### Introduction

This example demonstrates the use of the vtkLinearSubdivisionFilter and vtkButterflySubdivisionFilter.

In order to see the effects of these filters, a triptych is created that demonstrates the effect of applying the filter to a selected source such as a cone.

Whilst a default source consisting of a cone is provided, the user can select from a list of sources to render and also:
- Specify whether normals are displayed.
- What type of shading to use.
- The number of normals to glyph.

The user is encouraged to experiment with different sources to see the effect of the filters.

Additionally the use of labels and orientation markers are also demonstrated.

#### Adding more sources.
A representative set of sources to render are provided in the class called **Sources**. 

If you add more sources, you may need to provide one or all of these filters:
 - A Triangle filter
 - A Normal filter
 - An elevation filter.
 - A CleanPolyData filter.
 - For parametric sources, you may need to apply one of both of **JoinUOff()** or **JoinVOff()**.

The representative sources provided in the class **Sources** should provide good templates.
