TITLE: Twisted
NAME: Richard Webster
COUNTRY: England
EMAIL: irtc_mail@yahoo.co.uk
WEBPAGE: None
TOPIC: Force of Nature
COPYRIGHT: I SUBMIT TO THE STANDARD RAYTRACING COMPETITION COPYRIGHT.
MPGFILE: twisted.mpg
ZIPFILE: twisted.zip
RENDERER USED: 
    povray 3.5

TOOLS USED: 
    cmpeg

CREATION TIME: 
    14 hours

HARDWARE USED: 
    AMD Duron 1.1GHz 128MB

ANIMATION DESCRIPTION: 


 While everyone is out storm-chasing, a tornado creates its own logo.


VIEWING RECOMMENDATIONS: 
    Tested in Windows Media Player and mpeg_play

DESCRIPTION OF HOW THIS ANIMATION WAS CREATED: 


 All frames were rendered at 320x240 with anti-aliasing.

 All modelling was done in code and the full source is in the zip file.

 Units are in metres (approximately) with small scale-things larger and
 large-scale things smaller than they should be.

 The main elements are as follows:

 - Scene

   A ground plane and a sky plane, both with random textures, and white fog
   for mist.

 - Building

   A set of polygons which is included in a CSG object to make it disappear
   as it is destroyed.

 - Flag

   The flag pole is a sphere-sweep with control points allowed to move more
   the higher they are.
   
   The small flapping flag is a small mesh which has a normal pattern with
   translation linked to the clock.

   The close-up flag is a large mesh generated from a function which puts
   waves across the surface with their phase linked to the clock.

   The flag design is rendered into a separate image map file and uv-mapped
   onto the flag meshes.

 - Twister

   The twister is a funnel-shaped mesh.

   The texture is a random pattern, similar to the sky, which is given a
   spherical warp before being applied to the mesh. This means that a
   translation of the original pattern is seen as a rotation of the warped
   pattern, with points at different heights rotating at different speeds.

   Having just one warped pattern created a visible join so the texture
   uses two warped patterns, each with their joins in a different place,
   and a further radial pattern is used to blend the two warped patterns
   together so their joins are never visible. There is probably a simpler
   way of doing this.

   The formation and the dispersal of the twister is done by having a
   `density' parameter which controls the value in the colour map at which
   the colour switches from solid to clear.

 - Air Debris

   Each piece of debris in the air follows a path in cylindrical coordinates
   and each is given a different start time.

 - Furniture

   Simple larger-than-life block models.

 - Ground Debris

   A second version of the flag design, without the text, is used to
   position the debris in the final scene. The design is used as an image
   map whose pigment is evaluated to give the test for placing each object.

