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