POV-Ray : Newsgroups : povray.general : Possiable sor bug Server Time
1 Aug 2024 22:17:01 EDT (-0400)
  Possiable sor bug (Message 1 to 2 of 2)  
From: Harry
Subject: Possiable sor bug
Date: 8 Apr 2005 15:03:53
Message: <4256d599$1@news.povray.org>
Okay I haven't done a lot of ray tracing recantlly so I could be wrong 
about this.  Also, I'm running this with the 3.6.1 windows 64bit 
version.  Now the bug is that  you have a sor and a light source 
perpindular to the axis of rotation e.g. sor from 0 to 10 around the y 
axis, I'm refering to any light with an y value of 0 to 10.  So you the 
get shaddow dot on the sor in two bands near the  y value of the light 
(one above one below).  These bands also appear on the inside of the 
sor.  Finally if you have an object behind the light you get simlar 
bands in the SOR's shadow.  Finally the size of the bands appears to be 
proportional to the distance the sor is from the light.

I am gusseing that that this is the result of the the rays not being 
able to get to the light source.  The spots in the objects shado I think 
could be from the light rays going through the sor when the angle with 
respect to the vector of rotation is low.

Okay thats it.

//EXAMPELE 1:
   #include "colors.inc"
   #include "golds.inc"
   camera {
     location <10, 15, -20>
     look_at <0, 5, 0>
     angle 45
   }
   light_source { <25, 2, -25> color rgb 1 }
   light_source { <10, 9.5, -10> color rgb 1 }

   plane {
     y, 0
     pigment { checker color Red, color Green scale 10 }
   }

   sor {
     8,
     <0.0,  -0.5>,
     <3.0,   0.0>,
     <1.0,   0.2>,
     <0.5,   0.4>,
     <0.5,   4.0>,
     <1.0,   5.0>,
     <3.0,  10.0>,
     <4.0,  11.0>
     open
     //sturm
     texture { T_Gold_1B }
   }

//EXAMPLE 2:
#include "colors.inc"
#include "stones.inc"
#include "textures.inc"

camera
{
         location <-3,4,-4>
         look_at  <0,0,2>
         rotate y*30
}

plane{
y, -2
pigment{checker color Green, color Blue }
}

sor{
         //linear_spline
         7
         <0,-2>,<1,-2>,<1,1>,<.7,1.1>,<1,1.5><1,2>,<0,2>
         open
         translate<1,0,5>
        // sturm
         pigment{ color Magenta }
         //texture { T_Stone2}
}


cone {
<3,-2,4>,1
<3,2.8,4>,1.4
texture{ T_Stone29 }
}


//light_source{ <3,10,4> color Red }
light_source{ <-80,0,5.1> color White}
light_source{ <3.5, -1, -4> color White}

light_source{ <2,4,-1> color White}


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From: Le Forgeron
Subject: Re: Possiable sor bug
Date: 11 Apr 2005 04:31:32
Message: <425a35e4$1@news.povray.org>
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You might be on something, but...
that's why the sturm solver is also available!
(it's not default, because it is slower and needed rarely!)

just activate the sturm option and no more problem!
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