TITLE: The Piano NAME: Maurizio Tomasi COUNTRY: Italy EMAIL: zio_tom78@hotmail.com WEBPAGE: http://www.geocities.com/zio_tom78 TOPIC: Great Inventions COPYRIGHT: I SUBMIT TO THE STANDARD RAYTRACING COMPETITION COPYRIGHT. JPGFILE: mtpiano.jpg ZIPFILE: mtpiano.zip RENDERER USED: POVRay 3.5 for Windows TOOLS USED: - Paint Shop Pro 8.0 (creation of image maps, JPEG conversion, title) - Wings 3D (used only for extracting vertex coordinates; see below) - sPatch 1.5 (column under the keyboard) RENDER TIME: Standard image size (1024 x 768) Time For Parse: 0 hours 0 minutes 7.0 seconds (7 seconds) Time For Trace: 1 hours 3 minutes 36.0 seconds (3816 seconds) Total Time: 1 hours 3 minutes 43.0 seconds (3823 seconds) Poster (1536 x 1152; included in the ZIP file) Time For Parse: 0 hours 0 minutes 8.0 seconds (8 seconds) Time For Trace: 2 hours 1 minutes 19.0 seconds (7279 seconds) Total Time: 2 hours 1 minutes 27.0 seconds (7287 seconds) HARDWARE USED: AMD Athlon 1000 Mhz with 384 MB RAM. IMAGE DESCRIPTION: This is a view of my vertical piano (a Georg Hoffmann built in the 1920s; keys are made by ivory). I tried here to reproduce the mechanics of my instrument as faithfully as possible. In any piano, each key has one or more strings associated with it. Lower notes require one heavy string (usually made with copper), while upper notes have two or three strings (copper or steel -- that's the reason why there are more screws on the right of the soundboard than on the left). When you strike a key, the hammer pushes the strings and immediately falls back to its original position. When you release your finger, the damper above the hammer pushes the oscillating strings and stops them. At high frequencies natural friction is enough to quickly stop oscillation: that's the reason why the upper 20 keys have no dampers. Hammers and dampers do not form an uniform row: you can notice two small gaps at C-2 (where C-3 is the middle C) and E-4. This is because of the presence of two backings in the soundboard, placed among the strings. Together with a cast iron soundboard, these are to strenghten the overall structure, since the tension of steel and copper strings is very strong, and if one does not use such reinforcements the piano might even collapse! Because of their length, strings cannot be placed vertically. Instead, they are tilted and cross themselves behind the row of hammers. This is the reason why dampers are not placed exactly above the hammers: only with such a geometry they can act on the same strings. My first thought was to use a very bright illumination to show each detail described in this text. But then I considered that such a thing was like an autpsy: it would have stolen the poetry behind this marvellous instrument. There is something unexplainable behind a piano: how can this bunch of machinery produce such astonishing emotions? This is the reason why I switched to the current lighting model: the weak light does not let the observer to reveal the piano's secrets by seein its details, only to hint them among the shadows. DESCRIPTION OF HOW THIS IMAGE WAS CREATED: To find the right size of every object, I simply opened my piano and measured it with a ruler. The image is made by simple primitives and CSG. The soundboard is an height field drawn with Paint Shop Pro. Finding the right position of each screw on the soundboard was quite difficult: I managed it in the following way. I shot a photo of my piano and used it as the texture of a plane in Wings3D. Then, for each screw I placed a small sphere on it. I exported the model as a Wavefront OBJ file. A simple C program extracts the list of vertexes of each sphere and write the coordinate of its mean point into a POV file, which was copied into nails_pos.inc (included in the ZIP file). A couple of vertexes were adjusted by hand to fit better the scale of the soundboard. There are two lights in the scene: the first is the candle on the left, while the second is a blue light placed on the right. Radiosity was used to increase the overall brightness. If you want to look how the image looks under a bright environment, set LIGHT_MODEL_NUM to 1 and USE_RADIOSITY to "true" in file "mtpiano.pov" (this renders faster than the default setting: on my computer the 1024x768 image takes about 45 minutes). The ZIP file contains a larger version of the image, where some smaller details are better visible. Maurizio Tomasi, April 2004