TITLE: The wet bird
NAME: Gilles Tran
COUNTRY: France
EMAIL: tran@inapg.inra.fr
WEBPAGE: http://www.mediaport.net/Artichaud/Tran
TOPIC: City
COPYRIGHT: I SUBMIT TO THE STANDARD RAYTRACING COMPETITION COPYRIGHT.
JPGFILE: gt_city.jpg
ZIPFILE: gt_city.zip
RENDERER USED: 
    Megapov 0.4

TOOLS USED: 
    Poser 4, sPatch, 3DS2Pov, Crossroads, UVMapper, Picture Publisher

RENDER TIME: 
    21 hours

HARDWARE USED: 
    Pentium 133 (general design, modelling), Pentium 200 (tests),
Pentium II 350 (final tests and final renders)

IMAGE DESCRIPTION: 

One city, one man, one bird

DESCRIPTION OF HOW THIS IMAGE WAS CREATED: 

When the subject was announced, I was both happy and worried. Happy because
"City" is a favourite subject of mine and worried because I had made quite a
number of city pictures. I had exhausted my stock of urban fantasies and didn't
want to make another "something strange happens here" picture, or model another
building. Then I realised that one thing I hadn't really done yet was to make a
"realistic" picture that would capture in 3D something of the real atmosphere
of a real city, while twisting it here and there (it's New York and not New
York), but in a much less blatant form than it is usual for me. So here it is.
The zip file contains some of the props used in the scene.
Here are the particulars, credits and a few technical comments.

General
This image is a real demo for Megapov (and possibly POV 3.5) since it uses
isosurfaces, motion blur, focal blur (post process), variable reflection, image
pattern, no_reflection, mesh2, uv mapping, oriented area lights, the facet and
cells patterns and reset_children. It also makes a big use of image maps,
height fields, area lights and meshes found on 3D model sites.

Character
The bird is an image map with an alpha channel put on a box
The ghost is the Poser 4 businessman with his trenchcoat. The umbrella was found
on the net. Both were exported to 3DS and then converted to the mesh2 format
with 3DS2POV. The ghost is blurred with Megapov's motion blur feature, with a
low (10) number of frames.

Buildings
The first building on the left is derived from pictures I took from a real one
in New York. It is pure CSG (with some help of my windows macro), textured with
an image map painted directly on an orthographic view of the model.
The second building on the left is made of a CSG frame textured with 30
different small image maps of windows and wall panes (scanned from a photo)
randomly assigned to CSG windows. The shop on the ground floor is CSG textured
with photos of shop windows.
The other buildings on the left are simple CSG constructs textured with tileable
images of real buildings.
The Chrysler building is a mesh found on the net (author unknown), converted to
the mesh2 format and uv-textured with an image map made of parts of the real
building mixed with other building pictures.
The building on the right is stock material (a large CSG) from a previous
scene.

Cars
All the cars were found in various 3D model sites (authors unknown). They were
converted to the mesh2 format and the taillights were added independently using
media spheres and boxes. There's a 64 Thunderbird, a Toyota, a Porsche, 2
Camaros, 2 Mercedes (including a limo), a Jaguar, a Montecarlo (?) and some
sort of low-detail Jeep. These 10 cars were replicated 12 times at not memory
cost (thanks to the mesh format).

Street and sidewalk
The sidewalk is made of a repeated height field and was built as follows. First,
the height field shape was painted in Picture Publisher and covered with
overlapping rectangles of different grey intensities. This image was used as a
basis for two images : (1) a contour filter provided the height field itself
(the cracks following the rectangles outline) ; (2) the blurred image was used
as an image pattern for the sidewalk texture. The texture is a texture map
mixing, through the image pattern, two textures with different finishes
(variable reflection and normal). The "wet" effect was obtained by averaging
several normal statements of different sizes. Note : I tried reflection
blurring first but it was too slow for the purpose.
Later on, I drew some random trash elements with sPatch, exported them as DXF,
converted them to meshes with Crossroads and arranged the trash randomly with a
while loop.
The street is an isosurface plane with noise3d. Its texture is similar to the
sidewalk's. The crossing marks are made with height fields and isosurfaces.
Street furniture

The street lamps and traffic lights are a mix of CSG constructs and sPatch
models. The shapes, sizes and proportions were (clumsily) derived from several
detailed photos. The "Don't walk" image is a photo of the real thing.
The signs are photos of real NYC signs, heavily retouched and sometimes
rewritten.
The fire hydrant is based at 900n a model posted by Christophe Bouffartigue
(thanks Bouf) on the French Pov group. You can see a close-up of the original
in his own IRTC entry. It uses Chris Colefax chain link macro.
The news vending machines are all CSG with image maps on the right places.

Atmosphere
The atmosphere was created by the following elements. A sky plane with bozo
clouds gives some irrregular colour variation in the sky. A semi-transparent
fog give the fog effect. A vertical plane with a gradient y pattern (dark fog
colour at the bottom, transparent a the top) adds some fogginess at the bottom
and a larger plane of the same kind blocks the picture near the Chrysler
building. The colours were sampled from photographs and adjusted if necessary.
Finally, focal blurring was added with the post processing feature of Megapov.
Things that didn't make it in the scene : more trash (a coca-cola can, cigarette
butts, empty bottles), more street signs, exhaust fumes for the cars, better
textures for the buildings, better textures for the cars, better crossing
marks, detailed wiring for the street lights, more street furniture.


