TITLE: Shell X-Ray
NAME: Neal Delfeld
COUNTRY: US
EMAIL: delfeld@lycos.com
WEBPAGE: -
TOPIC: Frozen Moment
COPYRIGHT: I SUBMIT TO THE STANDARD RAYTRACING COMPETITION COPYRIGHT.
JPGFILE: xrayneal.jpg
RENDERER USED: 
    Povray

TOOLS USED: 
    XnView (http://www.xnview.com)

RENDER TIME: 
    ~30 minutes

HARDWARE USED: 
    amd 1400, 256mb ram

IMAGE DESCRIPTION: 


        The x-ray of a fictional shell.  Please reference Bert Myers' actual
shell x-rays for where I got the idea.
        X-ray's are generally not thought of in terms of captured moments, but _
like all photos and such truck _ are.  The idea of a singular moment is
actually used in such things as cat-scans, when a representation of a current
state of the brain is sought. That particular techonology is used to help
understand the state of a person's brain before and after a certain event, such
as the brain state of a paranoiac before and after a drug treatment, with the
snapshot moments before and after 'proving' that an actual change in a person
occrurred (though the practice seems more like phrenology than medical
evidence).   
        Gimp converted the image to JPEG, and did final image sizing (from 


DESCRIPTION OF HOW THIS IMAGE WAS CREATED: 


        Tried to use the "sphere sweep", but it left much to be desired in terms
of control of sphere radius and number of spheres used.  Instead, I placed
individual spheres through macros which imitate the sphere sweep.  
        The spheres were placed along a sine wave variation, then duplicated,
rotating the wave about a radius while increasing the scale.  This will make a
basic shell.  Through various variables, the shell will seem more and more
realistic.
        The whole scene is comprised of variations on the sine wave _ height
delta, height placement delta, spiral delta, number of spheres delta, number of
slices delta, and probably some I don't remember.
        The x-ray effect is actually very similar to a real x-ray.  The spheres
were made mostly filtering (i.e., rgbf <1,1,1,.9>) and then the object used the
"no_image" command.  When a plane is placed perpendicular to the camera veiwing
line, and a light source is placed along the camera viewing line, and the image
is between the light source and the plane, the shadow will imitate what happens
during an actual x-ray.  

Tips: 
        Make the light source parallel.  
        Make two versions of the shape _ one with few spheres, and one for final
rendering.
        Viewing and adjusting the outline of one shell slice is easier than
veiwng and adjusting the final shell.
        Be prepared for using over 20 thousands spheres to make a smooth final
shell.  One image had over 100K spheres, and took more time than I was willing
to wait to render.  
        There is no need for a constant number of spheres in each slice of the
shell.  The inner (smaller) shell rotations do not need many spheres, while the
outer rotations will demand a lot for smoothness.  
        If a shell is not going to be transparent, only the last 540 degrees of
rotation (360 + 180, or 1 _ turns) will probably be necessary.