================================================================
Tutorials
================================================================

simple3d and simple4d are tutorials for Simple_Viewer, a simplified
front-end to esve.  They also show how to to define 3D and 4D objects
for the esve engine.

If you find Simple_Viewer too restrictive then you can use Simple_UI
without Simple_Viewer in order to build a more flexible application
(see topeviewer).  If Simple_UI is still too restrictive then you can
always design your own GUI (see polynomialviewer).

The definition of a geometric object depends only upon rudimentary
types such as quaternions and complex numbers; in particular it does
not (and should not) require any esve headers other than the low-level
subpackages base/, geom/ surface/, and types/.

In this manner geometric objects are kept independent of the engine.
This, I hope, will make defining new objects easier and allow
higher-level objects to sit atop the current system without being
constrained in possibly inefficient ways.

For 4D objects the engine hook consists of a handful of methods you
define.  These are called by a template mechanism which does the
actual hooking.  On the other hand, defining 3D objects is much
easier; the only requirement is a draw() method.