TITLE: Magic Box
NAME: Micha Riser
COUNTRY: Switzerland
EMAIL: mriser@datacomm.ch
WEBPAGE: http://micha.virtualave.net/
TOPIC: imaginary worlds
COPYRIGHT: I SUBMIT TO THE STANDARD RAYTRACING COMPETITION COPYRIGHT.
JPGFILE: magicbox.jpg
ZIPFILE: magicbox.zip
RENDERER USED: 
    povray 3.1.Linux.gcc (unofficial version complied by Roland L.
 Parker) and some other versions of povray for developing 

TOOLS USED: 
    gimp (for the text and the jpeg conversion)

RENDER TIME: 
    31 min 44 s

HARDWARE USED: 
    Pentium II 350, 128 MB RAM

IMAGE DESCRIPTION: 

Three magic boxes  standing on a table, two of them  are closed and one opened 
to see its interior.

Okay,  this picture  needs some explanation.  Look at the 'Magic Box' standing 
nearest to you.  You see a little car standing  one the top of  the magic box, 
don't you? Now I should tell you to touch the car (but I don't because I don't 
want your monitor to have fingerprints on it.). Anyway, you would fail because 
there isn't anything standing on the magic box at all.  At the place where you 
see the car  there is  a hole!  You see inside  the magic box  and you see the 
reflection of the car  which is on the bottom of the box.  You can look at the 
interior of  the box,  there is  an opened magic box  on the right  behind the 
first one. It consists of two parabolic mirrors. I put the third magic box (on 
the left) to proof  that there is really nothing ON the magic box.  If the car 
would be really where you imagine it, it would intersect with the pencil.

The speciality with this mirror box is that,  in contrast to a normal mirrors, 
you get a 'real' image of the reflected object. That means you can walk around 
the box and the car doesn't move,  it looks still like it is really there.  Of 
course this works only up to a certain viewing angle.

How do these mirrors work?  Take a certain point of the car.  Because there is 
light shining on this point there are light rays going away from this point in 
all  directions.  The mirrors are  shaped in such a  way (parabolic)  that ALL 
these rays  meet on the  top of the mirror  box again  in one point  and so we 
can't differ whether these rays come from a real object or are just reflected.

Such tricks are often used in the world of magic.


DESCRIPTION OF HOW THIS IMAGE WAS CREATED: 

My physics  teacher showed  our class  such a box in reality.  The whole class 
was quite impressed.  I hadn't believe that such a thing is possible. So I got 
interested in how this thing was built. I had the idea to reproduce this thing 
with my ray-tracer. The problem was that I didn't know the exact shape of this 
box so I had to try out several and found out that it consists of some kind of 
parabolic mirrors.  But there were still some parameters which I had to adjust
by try-and-error till the reflected  image was exactly  on the top of the box. 
I don't know if the parameters which I finally used were the best ones because
the reflected car seems to be slightly distorted.

The car and the pencil are not created by myself,  I took them from the POVRay 
Objects Collection at http://twysted.net/povobjects.

Finally the picture was rendered with the settings +AA0.01 +J0.1.