|
 |
Hi !
i noticed that i could hardly fake "real arealight" present in usual
radiosity scenes (such as cornell box scene or Winosi competition scene for
instance) by using povray arealights.
I tried to add a angle dependant "strength" to fake real arealights (cosinus
law i assume) by using sphere with gradient transparency. (ok, ....only few
lines to add)
It seems very efficient in comparison with pure global illumination
renderings. however it is quite boring to tweak. It can be simple but with
more than 1 light source it is more difficult (because transparent layers
should not be seen by other light sources...)
Is this kind of arealight foreseen in future realeses of povray ? I know
that many renderers have this feature and since global illumination is not
very suitable for small light sources (I always got poor results), it could
be a noticable improvement, doesn't it ?
what do you thing ? is it tricky to code ?
(It is just a question that seems logical to me. Correct me if i am wrong ;
please note that i do not intend to do a stupid blame.)
You can notice though, that in cornell box scene in povray package, light is
faked by using a grid of spots with falloff to simulate cosinus law too (is
it linear in this case ?).
I think It is just another way to cope with global illumination issues with
small arealights.
Please find some experiments :
(1) fakeoriginal : the genuine povray arealight : 10 seconds
http://jcolin.site.voila.fr/galerie/GI/fakeoriginal10sec.jpg
fake : arealight surrounded by a sphere with an angle dependent transprency
texture : 27 seconds
http://jcolin.site.voila.fr/galerie/GI/fake27sec.jpg
real : simple small square with ambient = 1 and GI (i had to set count =
1600 to reduce spots) : 12 minutes
http://jcolin.site.voila.fr/galerie/GI/real12min.jpg
NB : the light size is the same = 1/5 of box length. the modified arealight
seems more accurate.
(2) cornell box scene with faked arealight : 10 minutes with recurtion limit
= 3
http://jcolin.site.voila.fr/galerie/GI/cornell10min.jpg
cornell trick : it shows the transparency layer for the same scene.
http://jcolin.site.voila.fr/galerie/GI/cornelltrick10min.jpg
(3) winosi scene : recution limit =3 (2 in reality + 1 arealight): 4 minutes
!!
http://jcolin.site.voila.fr/galerie/GI/winosi4min.jpg
I tried ith only global illumination and even with 1 day i cannot render a
good picture. Could you confirm ?
Coments are welcome
Kind Regards,
Jerome
---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.620 / Virus Database: 399 - Release Date: 12-Mar-06
Post a reply to this message
|
|
