pov-bspline 1.0
===============

What's it do?: This program takes x,y,z triplets for input, and
  outputs a .pov or .inc file with a b-spline made of cones and
  spheres.  

How to compile this thing: cc -o bspline bspline.c -lm

Then, type "bspline -h" to see a summary of the options.

syntax: bspline [options] < infile > whatever.pov
version: 0.2
options: -h   - This help.
         -i   - make a pov include file, not a pov scene file.
         -t n - Make spline n thickness. (default 1.0)
         -n n - Use n points per control point. (default 5)
         -p n - Degree of polynomial (2-6, default 4)

infile should contain only a list of x,y,z points to influence the b-spline.

An example infile would look like:

0 0 0
1 0 0
1.5 1 0
1 2 0


(etc, etc..)  Just the coordinates of the "control points".  

The b-spline starts and ends at the first and last control point, but
does not necessarily go through all of the other points.  The other
points influence the direction of the spline.  A spline that actually
goes through all the points is a cubic spline.  This program does not
(yet) support cubic splines.  

Note that this is version 1.0.  Brand new.  I wrote this in one
afternoon.  There may be problems lurking inside of it.  If you find
one, or you add some feature (be it neat-o or merely pedestrian), mail
me (meek@alpha2.csd.uwm.edu).  I'd be very grateful. 
  
The options:

-h  Help.  

-i    Make an include file.  This omits the standard boilerplate camera
      and light source.  Just output it to a .inc file, and #include it
      in your favorite scene.

-t n  Make the spline n units thick, where n is a floating point
      number.  Imagine the spline as a snake.  This is how fat the
      snake is.

-n n  This puts n points per control point in the spline.  Higher
      values of n lead to smoother curves.  Too high makes your
      rendering mighty slow.   The default is 5.

-p n  Use degree n of polynomial.  Degree 2 is the moral equivalent
      of connect-the-dots; you'd have your points connected by
      straight lines, not splines.  If you do that, also do "-n 1".
      Each higher degree is less influenced by the points, and would
      be "straighter".  Like everything in raytracing, it's best
      to keep experimenting with the values, until you get something
      that looks 'right'.

I hope this program is of some utility to you..

-Michael