TITLE: impossible NAME: Rob Wieringa COUNTRY: The Netherlands EMAIL: wieringa@natlab.research.philips.com WEBPAGE: -- TOPIC: Physics & Math COPYRIGHT: I SUBMIT TO THE STANDARD RAYTRACING COMPETITION COPYRIGHT. JPGFILE: impos.jpg ZIPFILE: impos.zip RENDERER USED: povray 3.0 TOOLS USED: penta (see below) RENDER TIME: 0 hours 28 minutes 38.0 seconds (1718 seconds) HARDWARE USED: Sun Solaris SPARC5 IMAGE DESCRIPTION: This image shows a physically impossible figure. It looks like three dumb-bell like objects, that do not touch, but are intertwined indissoluble. I have been an admirer of the Dutch graphical artist Escher (graphical in the classical sense, nothing to do with computer graphics ;-) ) for years and years, and his impossible figures intrigued me in particular. I discovered the one displayed here more or less by accident, and a line drawing (using square "toruses") has been my "logo" for a while. DESCRIPTION OF HOW THIS IMAGE WAS CREATED: When POV3 came out with the orthographic camera, I realised that this impossible figure was an excellent application. As in all impossible figures, the camera position is essential. Two of the three dumb-bells are real, the third one is a fake, and consists of two pieces, perfectly in line due to the camera position. The picture asked for a special color scheme. I exploited the "programming" facilities of POV3, and wrote a general-purpose HSV to RGB converter ("colcirc.inc"). On top of that comes (both for the background and for the dumb-bells) a loop that generates a color map consisting of a set of color bands running through (a part of) the color circle. These maps-loops are used in a pigment (marble with 41 colors for the background, bozo with 5 colors for the dumb-bells) giving the effects visible in the picture.