EMAIL: mriser@datacomm.ch NAME: Micha Riser TOPIC: imaginary worlds COPYRIGHT: I SUBMIT TO THE STANDARD RAYTRACING COMPETITION COPYRIGHT. TITLE: Magic Box COUNTRY: Switzerland WEBPAGE: http://micha.virtualave.net/ 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.