POV-Ray : Newsgroups : povray.binaries.images : Radiosity: Algorithm vs. Reality : Radiosity: Algorithm vs. Reality Server Time
18 Aug 2024 18:14:02 EDT (-0400)
  Radiosity: Algorithm vs. Reality  
From: news povray org
Date: 20 Mar 2001 09:34:16
Message: <3ab76a68@news.povray.org>
First: I've not that much experience with radiosity; maybe I'm just
using the wrong parameters...

I wanted to try something simple, when I saw the radiosity pic of
Tony[B]...

I've put a sphere on a checkered plane (hehe, typical POV), made a
blue background and  added a ground fog, to give it some depth.
The light is far away and is an area(9,9)light

Then I added +QR and waited (6hrs)...

There are 2 things, that I see...
I know that the algorithms work this way but it doesn't seem realistic
(How realistic is a single Sphere on a checkered plane?)..

the obvious thing is that the crackles aren't lit by the environment
by radiosity, but only by the sunlight ...

the second thing, (I'm not sure about this) is that there is this edge
on the sphere, that makes it seem, to be a mirror...
In the lower half the sphere is brighter, than the upper half. It's
from the radiosity, reflecting the groundfog-brightness ...
But I didn't expect such a sharp edge ... Maybe I'm wrong ...

except these things it looks quite beautiful .. (I'think)
Because it's short, I've attached the source here ...

Comments and hints are welcome...

--
background{rgb 1}camera{location<1,5,-2>look_at 0}#macro
m(a,b,i)#local d=(b-a)
/8;#local
e=vcross(d,y);#if(i)m(a-e,a+e+2*d,i-1)m(a+e,a+2*d-e,i-1)m(a+3*d-e,a+e
+3*d,i-1)m(a+3*d-e,a+5*d-e,i-1)m(a+6*d-e,a+e+6*d,i-1)m(a+8*d-e,a+e+8*d
,i-1)#else
cylinder{a,b,vlength(d)/3 pigment{rgb 0}}#end#end m(-4*x,2*x,4) // Jan
Walzer

---------source_start--------------
#version unofficial MegaPov 0.7;
global_settings {
        assumed_gamma 1
        radiosity {
                brightness 1
                count 512
                error_bound 0.15
                nearest_count 10
                recursion_limit 3
        }}
background {color rgb <0.0,0.30,0.80>}
fog {   fog_type 2
        distance 1000
        color rgbt <1,1,1,0.1>
        fog_offset 0
        fog_alt 50
        up y
        }

#declare l_size=1000;

#declare GroundTex=texture {
                        pigment {checker color rgb 1, color rgb 0.95}
                        finish {ambient 0 diffuse 0.8}
                        }
light_source {<10000,10000,5000>,
        color rgb <1,0.95,0.5>*1
        area_light
                <0.5,0,-1>*l_size,
                <0,1,0>*l_size,
                9,9 jitter
        }

camera {location <0,10,-30>
        look_at <-5,5,0>
        angle 55
        }

plane { y, 0
        texture {GroundTex}
        }

sphere {y*6,5.5
        texture {GroundTex
                normal {
                        crackle 1
                        scale 0.5
                        }
                }
        }

----------source_end----------------


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Attachments:
Download 'radiosity_test.png' (112 KB)

Preview of image 'radiosity_test.png'
radiosity_test.png


 

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