This python module is for the rendering of a simulated 3D world by raytracing.
The dependencies for this module are outlined at the bottom of this readme.

Use of this module flows as follows.

    * import the pytrace module (and the py3D module)
    * instantiate a Sky object (parameters are vector to 'sun' and color of sky)
    * instantiate some number of Body objects from py3D module
    * instantiate World object
    * add bodies to world ('add_body() method')
    * instantiate a Camera object
        * position
        * focal point
        * width in units
        * height in units
        * orientation vector (which way is up)
    * change pixels per unit with Camera's 'set_ppu()' method (default 100)
    * instantiate a Tracer object
        * world object
        * camera object
    * use Tracer.draw(n) to draw image
    * use Tracer.write(filename) to output to file

########## Example Code ##########
import raytrace
p = raytrace.CheckPlane
w = raytrace.World([p], raytrace.Sky( raytrace.Vector(0.0,1.0,10.0))
c = raytrace.Camera(Vector(0.0,1.0,0.0), Vector(0.0,0.0,1.0))
t = raytrace.Tracer(w, c)
t.draw().write()
########## End  Example ##########

DEPENDENCIES:
    py3D  -- for instantiation of bodies
    pypng -- for creation of output image.
    pybin -- dependency of pypng