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I forgot to add that B) has a relatively low reflection of say 0.2.
Another thing about radiosity, If you have only smooth reflective surfaces
in a scene, adding radiosity should make basically no difference to the
scene. Right?
Nekar
"Nekar Xenos" <vir### [at] icon coza> wrote in message
news:3aba0ecd@news.povray.org...
> Ok, let's use some examples on the radiosity sample that comes with Povray
:
>
> A) Rendered with the best known settings for radiosity.
>
> B) Use isosurfaces or heightfields to make the roughness of real world
> texture, such as wall paint, etc. Use photon packs for lighting and no
> radiosity.
>
> Which should look more real?
>
> Nekar
>
>
>
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Nekar Xenos wrote:
>
> Ok, let's use some examples on the radiosity sample that comes with Povray :
>
> A) Rendered with the best known settings for radiosity.
>
> B) Use isosurfaces or heightfields to make the roughness of real world
> texture, such as wall paint, etc. Use photon packs for lighting and no
> radiosity.
>
> Which should look more real?
>
Your B-version would not be a feasible solution. The surface structures
leading to diffuse scattering of light in reality are in micrometer
scale. Even if you use that accurate geometry there would be no effect in
Povray.
Photon mapping right now is good for large scale computation of reflection
and refraction, but not for realistic simulation of the detail effects.
Christoph
--
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other
things on: http://www.schunter.etc.tu-bs.de/~chris/
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Nekar Xenos wrote:
>
> I forgot to add that B) has a relatively low reflection of say 0.2.
>
> Another thing about radiosity, If you have only smooth reflective surfaces
> in a scene, adding radiosity should make basically no difference to the
> scene. Right?
>
Radiosity (in megapov) uses the diffuse finish component for calculation
(and of course ambient for emission). If you set diffuse and ambient to 0
on all objects, there will be no effect. This has nothing to do with the
surfaces being smooth or not.
Christoph
--
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other
things on: http://www.schunter.etc.tu-bs.de/~chris/
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As I understand you B) would work with a ridiculously high resolution?
Nekar
"Christoph Hormann" <chr### [at] gmxde> wrote in message
news:3ABA1641.D8617F72@gmx.de...
>
>
> Nekar Xenos wrote:
> >
> > Ok, let's use some examples on the radiosity sample that comes with
Povray :
> >
> > A) Rendered with the best known settings for radiosity.
> >
> > B) Use isosurfaces or heightfields to make the roughness of real world
> > texture, such as wall paint, etc. Use photon packs for lighting and no
> > radiosity.
> >
> > Which should look more real?
> >
>
> Your B-version would not be a feasible solution. The surface structures
> leading to diffuse scattering of light in reality are in micrometer
> scale. Even if you use that accurate geometry there would be no effect in
> Povray.
>
> Photon mapping right now is good for large scale computation of reflection
> and refraction, but not for realistic simulation of the detail effects.
>
> Christoph
>
> --
> Christoph Hormann <chr### [at] gmxde>
> IsoWood include, radiosity tutorial, TransSkin and other
> things on: http://www.schunter.etc.tu-bs.de/~chris/
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Nekar Xenos wrote:
>
> As I understand you B) would work with a ridiculously high resolution?
>
Maybe if you want the view of a painted wall under a microscope :-)
Christoph
--
Christoph Hormann <chr### [at] gmxde>
IsoWood include, radiosity tutorial, TransSkin and other
things on: http://www.schunter.etc.tu-bs.de/~chris/
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I think this may be relevant:
I once saw a web page a few years ago ( I can't find it now ) where an
Imagine user faked radiosity by adding tiny amount of small-scale noisy-bump
and minimal reflection to everything in the scene. He then rendered it at
double the intended resolution without AA (for speed reasons). After
resizing the image in a paint program (AA done here), the effect was very
much like radiosity with lightening in the shadowed areas and nominal color
bleed.
I haven't tried it, but I bet it would work the same in PoV. If this is sort
of what you're talking about then, it wouldn't work on perfectly smooth
surfaces, and iso's and photons, while not hurting anything, might be
overkill.
bat### [at] cadronhsacom
Nekar Xenos wrote in message <3aba0ecd@news.povray.org>...
>Ok, let's use some examples on the radiosity sample that comes with Povray
:
>
>A) Rendered with the best known settings for radiosity.
>
>B) Use isosurfaces or heightfields to make the roughness of real world
>texture, such as wall paint, etc. Use photon packs for lighting and no
>radiosity.
>
>Which should look more real?
>
>Nekar
>
>
>
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"Batronyx" <bat### [at] cadronhsacom> wrote in message
news:3abab191$1@news.povray.org...
> I think this may be relevant:
> I once saw a web page a few years ago ( I can't find it now ) where an
> Imagine user faked radiosity by adding tiny amount of small-scale
noisy-bump
> and minimal reflection to everything in the scene. He then rendered it at
> double the intended resolution without AA (for speed reasons). After
> resizing the image in a paint program (AA done here), the effect was very
> much like radiosity with lightening in the shadowed areas and nominal
color
> bleed.
This is exactly what I had in mind. In my mind tho', this is not fake, but
what radiosity should be.
> I haven't tried it, but I bet it would work the same in PoV. If this is
sort
> of what you're talking about then, it wouldn't work on perfectly smooth
> surfaces, and iso's and photons, while not hurting anything, might be
> overkill.
If a surface is perfectly smooth it would be reflective so radiosity
shoulkdn't have any effect anyway. Why wouldn't isosurfaces and photons
work? I haven't studied them yet, but I'm very keen to(so little time and
so much to do)...
Nekar
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I am saying they probably 'will' work. But why waste the extra CPU cycles to
use iso's when perturbed normals are likely just as effective?
(Given the size of the microfacets). I really can't say about the photons
though. Like you, I haven't really studied them yet. :)
bat### [at] cadronhsacom
Nekar Xenos wrote in message <3abaec19@news.povray.org>...
>
>"Batronyx" <bat### [at] cadronhsacom> wrote in message
. . .and iso's and photons, while not hurting anything, might be
>> overkill.
>
>If a surface is perfectly smooth it would be reflective so radiosity
>shoulkdn't have any effect anyway. Why wouldn't isosurfaces and photons
>work? I haven't studied them yet, but I'm very keen to(so little time and
>so much to do)...
>
>Nekar
>
>
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In article <3ab9f02f@news.povray.org>, "Nekar Xenos"
<vir### [at] iconcoza> wrote:
> If I understand it correctly, the purpose of radiosity is to
> compensate for light scattered by rough surfaces. Normals, as I
> understand don't do this right without radiosity which is why you
> need to add radiosity.
> Therefore if you were to use isosurfaces or heightfields to make rough
> textures with a relatively low reflection level and a high maximum
> iteration
> level, you wouldn't need to add radiosity.
I've experimented with something similar using blurred reflection. You
don't need isosurfaces or blurred reflection, normals would work fine,
but you will need hefty antialiasing settings. And it will be
excruciatingly slow...
The reason radiosity exists as a separate feature is that it can be much
faster and smoother that way, as well as easier to use. There are many
optimizations that can be done with radiosity calculations but not
blurred reflection calculations.
--
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/
<><
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You're right about normals. I had this thing against normals because they
look flat when viewed from the side. But seeing it's so small it doesn't
matter. I actually think photons might even work better or maybe you won't
see any difference any way...
Nekar
"Batronyx" <bat### [at] cadronhsacom> wrote in message
news:3abb3a6c$1@news.povray.org...
> I am saying they probably 'will' work. But why waste the extra CPU cycles
to
> use iso's when perturbed normals are likely just as effective?
> (Given the size of the microfacets). I really can't say about the photons
> though. Like you, I haven't really studied them yet. :)
>
> BatronyxT ^"^
> bat### [at] cadronhsacom
>
>
> Nekar Xenos wrote in message <3abaec19@news.povray.org>...
> >
> >"Batronyx" <bat### [at] cadronhsacom> wrote in message
> . . .and iso's and photons, while not hurting anything, might be
> >> overkill.
> >
> >If a surface is perfectly smooth it would be reflective so radiosity
> >shoulkdn't have any effect anyway. Why wouldn't isosurfaces and photons
> >work? I haven't studied them yet, but I'm very keen to(so little time
and
> >so much to do)...
> >
> >Nekar
> >
> >
>
>
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