EMAIL: rclee@oklahoma.net
NAME: Robert Lee
TOPIC: Old Technology
COPYRIGHT: I SUBMIT TO THE STANDARD
RAYTRACING COMPETITION COPYRIGHT.
TITLE: Siege
COUNTRY: USA
WEBPAGE: None
RENDERER USED: POV 3.5
TOOLS USED: IFranView, Little Gray Cells

RENDER TIME: about 56 hrs
HARDWARE USED: 1.7 Ghz Pentium on Windows XP

IMAGE DESCRIPTION: For good or ill the siege
begins under the blood-red light of a fully 
eclipsed moon. The attacking army is encamped 
a short distance away, suggested by the fires 
in the distance.

Today, the trebuchet is considered old technology.
In its day, however, it was considered advanced 
technology, one of the most feared siege weapons
ever built.

The image brightness should be set so that the
stones at the bottom of the moat are just visible.

This is my fourth IRTC entry.

DESCRIPTION OF HOW THIS IMAGE WAS CREATED:

I wanted a panaramic feeling of epic proportion, so 
this entry was rendered with +w1024 +h512.  To 
reduce jaggies, +aa 0.3 was used.

Castle: I would like to thank Gilles Tran for making
his MAKEWALL macro available.  I did not make any large 
changes to his code except for modifying his textures
a bit.

Terrain: An isosurface was used to generate the 
snow cover.

Moat: The moat was carved out of the ground plane with
a sphere sweep object and textured with a crackle 
pattern to simulate stones on the bottom.  The water
was created by adding a box to the plane-sphere sweep
difference.  The box was textured with a water material.
The water transparency was adjusted using a filter 
value so that the stones at the bottom of the moat would
be slightly visible.

Foliage:  The bulrushes around the moat and in the snow
to the right are randomly rotated and placed sphere sweep
objects.  The bushes / trees in the background are scaled-up
clumps of bulrush objects.

Fog:  Ground fog was added in the background and an
emission media, enclosed by an invisible box, was 
used in the foreground to show smoke from the fires.

Stars:  These are randomly colored and placed spheres.
If the spheres became too small, the +aa 0.3 setting 
made them invisible.

Trebuchets: These were modeled and textured using POVRay 
3.5 CSG.

Arrows: Shot from above, arrows were modeled using CSG
and placed in the scene by randomly generating locations
above and below a tilted plane.

Rocks and Ropes: The rocks are super superellipsoids and 
the rope is made out of a sphere sweep object textured 
with a spiral pigment.

Soldiers:  I was desperate to show the scale of the 
trebuchets.  Lacking additional software, I downloaded
several bitmaps from the internet, mapped them to 
transparent boxes, and set them in the scene.  The scaled
soldiers were too small to be seen among the distant
campfires.

Moon: The moon is a bitmap of the moon's surface maped to 
a sphere.  When the size of the sphere was reduced to make
a realistic looking moon and +aa 0.3 was applied, the 
details of the bitmap were lost.  However, during a total 
lunar eclipse, the details of the lunar surface can not be
seen very well; so this rendition ends up looking like the 
real thing.

Fires: Logs for the fires were taken from the plankes used
to build the trebuchets.  However, these logs were textured
to suggest burning coals.  The fires are made up of colored
emission and scattering media contained by blob objects.  
Each fire has a light source imbedded in it. The nearest 
fire contains a small area light to make a nice shadow of 
the soldier on the nearest trebuchet.  All the other fires 
contain a regular point light source. 

Ambient light: To light the overall scene, a point light 
source, appropriately colored, was set directly in front 
of the moon.

Radiosity: I used fairly high quality radiocity settings:                
        pretrace_start 0.08
        pretrace_end   0.008
        count 200   
        error_bound 0.25
        recursion_limit 3  
        media on
        normal on
        always_sample off
        save_file "CaveRad2"

There was little difference between the regular render and the
render with raiosity.  I suppose there would have been a bigger
difference if the sky had not been so dark.

IfranView was used to convert the PNG files to JPG.