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Radiosity seems to work wrong when used with very-small-angle perspective
camera.
Such camera can be used to simulated ortographics one, like
camera { angle 45/X location 10*X } with X = 10000;
instread of
camera { ortographics angle 45 location 10 }
When using such camera radiosity gets very strongly distored.
Only using extremly low minimum_reuse can partialy prevent that from
happening.
IMHO that could indicate that either there is a lost-precission problem,
or, despite what documentation states, minimum_reuse is based on angle
(like - each sample per 1 degree) not on pixels.
Rendered images and minimal code is on
http://www.raf256.com/povray/bug/radiosity-orthographic/
And below + on p.b.i
Change SHOW_BUG to see good version, bug, and partial fix.
// bug (problem) while immitating orthographic camera by
// standard-perspectiver camera with very narrow angle
// suggested: +w640 +h480 +a0.03 +am2 +r2 +fn
#declare SHOW_BUG = 1; // 0=normal 1=show bug 2=show bug + partialy fix
union {
box { -100, +100 pigment { rgb 1 } }
box { <-80,-80,+150> <+80,+80,0> pigment { rgb <1,0,0> } }
finish { ambient 0 }
}
camera {
#local FlatPerspective = 1.0;
#if (SHOW_BUG)
#local FlatPerspective = 5000.0;
#else
orthographic
#end
up y right x*(image_width/image_height)
angle 60/FlatPerspective
location 250*FlatPerspective
look_at 0
}
light_source { <500,2000,1000> rgb 1 }
global_settings { radiosity {
count 1600 error_bound 0.3 nearest_count 15 // very-high quality
//count 800 error_bound 0.6 nearest_count 12 // high quality
#if (SHOW_BUG=2)
minimum_reuse 0.000001
#end
} }
--
http://www.raf256.com/3d/
Rafal Maj 'Raf256', home page - http://www.raf256.com/me/
Computer Graphics
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