 |
|
|
|
|
|
| |
| |
|
|
|
|
| |
| |
|
|
With the camera and light above the following boxes, BoxA shows up as white
media, which is what I expected, but BoxB shows up as black - why is this?
After all, if you are looking down at a cloud from an airplane, beyond a
certain point the actual physical thickness of the cloud is not
particularily significant (is it?).
#declare BoxA = // nice 'n' white
box
{
<-10000, -1, -10000>
< 10000, 0, 10000>
pigment{rgbf<1,1,1,1>}
hollow on
interior{media{Plain_White_Scattering_Media}}
}
#declare BoxB = // completely black
box
{
<-10000, -10000, -10000>
< 10000, 0, 10000>
pigment{rgbf<1,1,1,1>}
hollow on
interior{media{Plain_White_Scattering_Media}}
}
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Tom Melly wrote:
>
> With the camera and light above the following boxes, BoxA shows up as white
> media, which is what I expected, but BoxB shows up as black - why is this?
> After all, if you are looking down at a cloud from an airplane, beyond a
> certain point the actual physical thickness of the cloud is not
> particularily significant (is it?).
Since no one else appears interested in answering your question, and I have
no informed answer for you myself, I will simply guess that the thicker
media container in example 2 will require a greater number of samples to
get similar results.
You didn't help much by not telling us what "Plain_White_Scattering_Media"
is either.
--
Ken Tyler - 1300+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Hm. Isn't that making a shadow then? If there's a light above the thinner
white media box then there should be a shadow of that media and the other also.
And then there's light_source 'media attenuation'... But like Ken said you
didn't say what the media statement has in it so it's tough to speculate on what
it's doing in the first place.
Bob
"Tom Melly" <tom### [at] tomandlu force9couk> wrote in message
news:38ce75e7@news.povray.org...
| With the camera and light above the following boxes, BoxA shows up as white
| media, which is what I expected, but BoxB shows up as black - why is this?
| After all, if you are looking down at a cloud from an airplane, beyond a
| certain point the actual physical thickness of the cloud is not
| particularily significant (is it?).
|
| #declare BoxA = // nice 'n' white
| box
| {
| <-10000, -1, -10000>
| < 10000, 0, 10000>
| pigment{rgbf<1,1,1,1>}
| hollow on
| interior{media{Plain_White_Scattering_Media}}
| }
|
| #declare BoxB = // completely black
| box
| {
| <-10000, -10000, -10000>
| < 10000, 0, 10000>
| pigment{rgbf<1,1,1,1>}
| hollow on
| interior{media{Plain_White_Scattering_Media}}
| }
|
|
|
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Sorry for lack of clarity - have reposted with full code to text.scene-files
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
I tried it out and although I don't fully know the reasoning behind it I found
putting extinction .0025 into the 'scattering' statement fixes it. The logic
seems right if there were 'media_attenuation on' in the light but I tried adding
that in as well with it both on and off, neither way makes a difference.
Check it out using 0.0033 for the extinction and it's interesting. My guess is
the missing link to 'density', it acts as though there is a 'density {rgb 1}'
present I believe and if approximately density {rgb .00025} (or lower) is used
then it corrects it (no need for extinction then either).
Bob
"Tom Melly" <tom### [at] tomandluforce9couk> wrote in message
news:38cfc981$1@news.povray.org...
| Sorry for lack of clarity - have reposted with full code to text.scene-files
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
I experimented breifly with the scene and found that the thicker BoxB is, the
more "spotted" with dark spots it gets, so by the time it gets a deep as you
have it, it has so many darker spots that it appears to be black with white
spots.
You can increase the intervals and samples of the media, but the cost in
rendering time is enormous. I don't recommend it, but it does increase the
white levels of the media.
Josh
Tom Melly wrote:
> With the camera and light above the following boxes, BoxA shows up as white
> media, which is what I expected, but BoxB shows up as black - why is this?
> After all, if you are looking down at a cloud from an airplane, beyond a
> certain point the actual physical thickness of the cloud is not
> particularily significant (is it?).
>
> #declare BoxA = // nice 'n' white
> box
> {
> <-10000, -1, -10000>
> < 10000, 0, 10000>
> pigment{rgbf<1,1,1,1>}
> hollow on
> interior{media{Plain_White_Scattering_Media}}
> }
>
> #declare BoxB = // completely black
> box
> {
> <-10000, -10000, -10000>
> < 10000, 0, 10000>
> pigment{rgbf<1,1,1,1>}
> hollow on
> interior{media{Plain_White_Scattering_Media}}
> }
--
Josh English
eng### [at] spiritonecom
"May your hopes, dreams, and plans not be destroyed by a few zeros."
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
> I experimented breifly with the scene and found that the thicker BoxB is,
the
> more "spotted" with dark spots it gets, so by the time it gets a deep as
you
> have it, it has so many darker spots that it appears to be black with
white
> spots.
>
Sounds right - I first ran into this using media with a hollow plane, then a
deep box before finally in a "one last try" mood using a thinner box.
> You can increase the intervals and samples of the media, but the cost in
> rendering time is enormous. I don't recommend it, but it does increase the
> white levels of the media.
>
Thanks for the suggestion, I'll try it out.
However, I suspect that this might just result in a less spots, more black -
I only say this as this is what I get in the MegaPOV which seems less prone
to "spotiness" in medias.
--
Tom Melly
tom### [at] tomandluforce9couk
http://www.tomandlu.force9.co.uk
Josh English <eng### [at] spiritonecom> wrote in message
news:38CFDD95.5A7EBD44@spiritone.com...
> I experimented breifly with the scene and found that the thicker BoxB is,
the
> more "spotted" with dark spots it gets, so by the time it gets a deep as
you
> have it, it has so many darker spots that it appears to be black with
white
> spots.
>
> You can increase the intervals and samples of the media, but the cost in
> rendering time is enormous. I don't recommend it, but it does increase the
> white levels of the media.
>
> Josh
>
> Tom Melly wrote:
>
> > With the camera and light above the following boxes, BoxA shows up as
white
> > media, which is what I expected, but BoxB shows up as black - why is
this?
> > After all, if you are looking down at a cloud from an airplane, beyond a
> > certain point the actual physical thickness of the cloud is not
> > particularily significant (is it?).
> >
> > #declare BoxA = // nice 'n' white
> > box
> > {
> > <-10000, -1, -10000>
> > < 10000, 0, 10000>
> > pigment{rgbf<1,1,1,1>}
> > hollow on
> > interior{media{Plain_White_Scattering_Media}}
> > }
> >
> > #declare BoxB = // completely black
> > box
> > {
> > <-10000, -10000, -10000>
> > < 10000, 0, 10000>
> > pigment{rgbf<1,1,1,1>}
> > hollow on
> > interior{media{Plain_White_Scattering_Media}}
> > }
>
> --
> Josh English
> eng### [at] spiritonecom
> "May your hopes, dreams, and plans not be destroyed by a few zeros."
>
>
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Tom Melly wrote:
>
> With the camera and light above the following boxes, BoxA shows up as white
> media, which is what I expected, but BoxB shows up as black - why is this?
> After all, if you are looking down at a cloud from an airplane, beyond a
> certain point the actual physical thickness of the cloud is not
> particularily significant (is it?).
Irel arj Zbenl/CBI-Enl MEDIA urer jvgu n ynetr urnqnpur samples gelvat
svther intervals pbeerpg yvtugvat ratio sbe fbzr pbzchgre blob tencuvp.
V nz hollow vzorpvyr gb inverse jvgu fb Voxel gnyxrq gb fbzr cebsrffvb
qrfvtaref naked gurls jrr gnyxvat nobhg gur x*3 yvtug zrgubq sbe yvtug
fprar.
And that is all I can add to this.
--
Ken Tyler - 1300+ Povray, Graphics, 3D Rendering, and Raytracing Links:
http://home.pacbell.net/tylereng/index.html http://www.povray.org/links/
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Many thanks - I'll play with those settings. I must confess that media still
mystifies me - as soon as I seem to be able to make a model in my head of
what it does, it goes and bites me in the arse. Why, for example, should the
extinction value be so significant - particularily as the docs advise that
the default is the most accurate representation? IMHO If x units thickness
of media show as white, then so should x+y (when the media is viewed from
the lighted side). Is this an inaccuracy? (the thick media showing as
black) - if so why does megapov compound the error?
--
Tom Melly
tom### [at] tomandluforce9couk
http://www.tomandlu.force9.co.uk
Bob Hughes <omn### [at] hotmailcom?subject=PoV-News:> wrote in message
news:38cfdd64@news.povray.org...
> I tried it out and although I don't fully know the reasoning behind it I
found
> putting extinction .0025 into the 'scattering' statement fixes it. The
logic
> seems right if there were 'media_attenuation on' in the light but I tried
adding
> that in as well with it both on and off, neither way makes a difference.
> Check it out using 0.0033 for the extinction and it's interesting. My
guess is
> the missing link to 'density', it acts as though there is a 'density {rgb
1}'
> present I believe and if approximately density {rgb .00025} (or lower)
is used
> then it corrects it (no need for extinction then either).
>
> Bob
>
> "Tom Melly" <tom### [at] tomandluforce9couk> wrote in message
> news:38cfc981$1@news.povray.org...
> | Sorry for lack of clarity - have reposted with full code to
text.scene-files
>
>
>
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
On Wed, 15 Mar 2000 12:14:06 -0800, Ken wrote:
>And that is all I can add to this.
What is that, some kind of Markov Chain/ROT13 thing? It's truly
beautiful; I haven't hit esc-R that much for one post in a long time.
--
These are my opinions. I do NOT speak for the POV-Team.
The superpatch: http://www2.fwi.com/~parkerr/superpatch/
My other stuff: http://www2.fwi.com/~parkerr/traces.html
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
|
|
