 |
|
|
|
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Op 13/12/2019 om 13:17 schreef And:
> Thomas de Groot <tho### [at] degroot org> wrote:
>>
>> Something that I do fairly often is to use separate, "layered", media
>> containers, separated by a minimal amount of space. This can be useful
>> e.g. in the case of different cloud layers. This way it is easy to
>> create (1) a water media, over which there is (2) an atmospheric media
>> (fog) with (3 etc) cloud layers above. The fact that the containers do
>> not overlap makes the render faster and avoids mutual media "contamination".
>>
>> --
>> Thomas
>
> you mean this?
> If I don't comprehend wrong.
>
yes.
--
Thomas
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
"And" <49341109@ntnu.edu.tw> wrote:
> "Bruno Cabasson" <bru### [at] cabassoncom> wrote:
> > "And" <49341109@ntnu.edu.tw> wrote:
> > > "Bruno Cabasson" <bru### [at] cabassoncom> wrote:
> > > >
> > > > Besides, real atmosphere is a very complex thing, not easy to model, and
> > > > real clouds are also quite complex and there are many kinds of them, each one
having a specific behaviour with
li
> gh
> > t.
> > >
> > >
> > > In fact, for a fully automatic volumn(cloud) renderer, it is not so different
> > > between different kind of cloud. The main difference of them is the height, and
> > > the shape(density map), and the average density(because a dense cloud needs more
> > > multiple scattering)
> > >
> > > ice droplets and liquid water droplets have different phase function when
> > > scatters light. but for a dense media(if light from sun light source collide
> > > many times in the cloud) the difference of the final appearance is small.
> > > And because water droplets almost never absorb light, represent the albedo of
> > > cloud almost 1.0( between visible wavelength range), so it is seldom eliminated
> > > in cloud, a light beam can collide hundred of times in a heavy cloud. You can
> > > see this:
> > >
http://news.povray.org/povray.binaries.utilities/message/%3Cweb.5bec15ae87bb2a51c8edf6b30%40news.povray.org%3E/#%
3C
> we
> > b.
> > > 5bec15ae87bb2a51c8edf6b30%40news.povray.org%3E
> > >
> > > This is the power(sp-radiance) at different level scattering output quantity.
> > > Maybe you can say the most of it still concentrated at first level. But this is
> > > an image contains a white cloud on the center, and the blue sky the other. It is
> > > the average sp-radiance on the whole image. If look at the cloud separately,
> > > the multiple scattering part is the dominate.
> > >
> > > And I attach a comparison. The image contains three images I rendered one year
> > > ago but should be the same (or similar) condition. They are 1 level, 3 level,
> > > and 27 level scattering renders.
> > > (up to down.)
> > >
> > >
> > >
> > >
> > >
> > >
> > > "Bruno Cabasson" <bru### [at] cabassoncom> wrote:
> > >
> > > > the rest is the same values, except the sun power and the parmeters for the
fog
> > > > media. Colors are obtained automatically thanks to media, mainly the
atmosphere
> > > > with rayleigh scattering.
> > > >
> > > > Regards
> > >
> > > When I watch this I guess you use scattering "extinction" not 1, because if you
> > > use correct extinction 1 and lacks of multiple scattering, your clouds
> > > is impossible so white. finally you use 0.25. When I use POV-Ray rendering
> > > cloud, I always find I need use filled lights or additional emission.
> >
> > Well... The fact is that I used exinction 0.25 for the cloud media for the
> > renders I posted in this thread. But a value of 1 is supposed to the the only
> > one realistic. I'll play with this, but I think it will not be dramatic.
> >
> > AKAIK, POV-Ray allows you to define several media within the same container
> > (they add together), and several density functions for each of them (they
> > multiply together). Therefore, you can complexify and enrich the model that way,
> > at the expense of render time (and carbon footprint). I'll also play with this.
> >
> > interior
> > {
> > // Media #1
> > media
> > {
> > <media1 parameters>
> > density
> > {
> > <media1/density1 function>
> > }
> > density
> > {
> > <media1/density2 function>
> > }
> >
> > .../...
> >
> > // Densities are multipled together for the current media
> > }
> >
> > // Media # 2
> > media
> > {
> > <media2 parameters>
> > density
> > {
> > <media2/density1 function>
> > }
> > density
> > {
> > <media2/density2 function>
> > }
> >
> > .../...
> >
> > // Densities are multipled together for the current media
> > }
> >
> > // More media
> >
> > .../...
> >
> > // Media contributions are added together
> >
> > }
> >
> > B.
>
>
> Thanks. But I don't understand <media2/density1 function> mean.., the /
> represent division?
Oh, sorry, it was not a division. I ment density1 for media1. I should have said
media1_density1, media1_density2, and so forth.
B.
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Thomas de Groot <tho### [at] degrootorg> wrote:
> Op 12/12/2019 om 15:25 schreef Bruno Cabasson:
> > "And" <49341109@ntnu.edu.tw> wrote:
> >> "Bruno Cabasson" <bru### [at] cabassoncom> wrote:
> >>>
> >>> Besides, real atmosphere is a very complex thing, not easy to model, and
> >>> real clouds are also quite complex and there are many kinds of them, each one
having a specific behaviour with li
gh
> > t.
> >>
> >>
> >> In fact, for a fully automatic volumn(cloud) renderer, it is not so different
> >> between different kind of cloud. The main difference of them is the height, and
> >> the shape(density map), and the average density(because a dense cloud needs more
> >> multiple scattering)
> >>
> >> ice droplets and liquid water droplets have different phase function when
> >> scatters light. but for a dense media(if light from sun light source collide
> >> many times in the cloud) the difference of the final appearance is small.
> >> And because water droplets almost never absorb light, represent the albedo of
> >> cloud almost 1.0( between visible wavelength range), so it is seldom eliminated
> >> in cloud, a light beam can collide hundred of times in a heavy cloud. You can
> >> see this:
> >>
http://news.povray.org/povray.binaries.utilities/message/%3Cweb.5bec15ae87bb2a51c8edf6b30%40news.povray.org%3E/#%3
Cwe
> > b.
> >> 5bec15ae87bb2a51c8edf6b30%40news.povray.org%3E
> >>
> >> This is the power(sp-radiance) at different level scattering output quantity.
> >> Maybe you can say the most of it still concentrated at first level. But this is
> >> an image contains a white cloud on the center, and the blue sky the other. It is
> >> the average sp-radiance on the whole image. If look at the cloud separately,
> >> the multiple scattering part is the dominate.
> >>
> >> And I attach a comparison. The image contains three images I rendered one year
> >> ago but should be the same (or similar) condition. They are 1 level, 3 level,
> >> and 27 level scattering renders.
> >> (up to down.)
> >>
> >>
> >>
> >>
> >>
> >>
> >> "Bruno Cabasson" <bru### [at] cabassoncom> wrote:
> >>
> >>> the rest is the same values, except the sun power and the parmeters for the fog
> >>> media. Colors are obtained automatically thanks to media, mainly the atmosphere
> >>> with rayleigh scattering.
> >>>
> >>> Regards
> >>
> >> When I watch this I guess you use scattering "extinction" not 1, because if you
> >> use correct extinction 1 and lacks of multiple scattering, your clouds
> >> is impossible so white. finally you use 0.25. When I use POV-Ray rendering
> >> cloud, I always find I need use filled lights or additional emission.
> >
> > Well... The fact is that I used exinction 0.25 for the cloud media for the
> > renders I posted in this thread. But a value of 1 is supposed to the the only
> > one realistic. I'll play with this, but I think it will not be dramatic.
> >
> > AKAIK, POV-Ray allows you to define several media within the same container
> > (they add together), and several density functions for each of them (they
> > multiply together). Therefore, you can complexify and enrich the model that way,
> > at the expense of render time (and carbon footprint). I'll also play with this.
> >
> > interior
> > {
> > // Media #1
> > media
> > {
> > <media1 parameters>
> > density
> > {
> > <media1/density1 function>
> > }
> > density
> > {
> > <media1/density2 function>
> > }
> >
> > .../...
> >
> > // Densities are multipled together for the current media
> > }
> >
> > // Media # 2
> > media
> > {
> > <media2 parameters>
> > density
> > {
> > <media2/density1 function>
> > }
> > density
> > {
> > <media2/density2 function>
> > }
> >
> > .../...
> >
> > // Densities are multipled together for the current media
> > }
> >
> > // More media
> >
> > .../...
> >
> > // Media contributions are added together
> >
> > }
> >
> > B.
> >
> >
>
> Something that I do fairly often is to use separate, "layered", media
> containers, separated by a minimal amount of space. This can be useful
> e.g. in the case of different cloud layers. This way it is easy to
> create (1) a water media, over which there is (2) an atmospheric media
> (fog) with (3 etc) cloud layers above. The fact that the containers do
> not overlap makes the render faster and avoids mutual media "contamination".
>
> --
> Thomas
Thats'a good thing, to my opinion. I don't really unerstand what you mean by
media "contamination". Do you mean that there are some issues if the containers
overlap? For my cloudscape experimental scenes, containers do overlap :
atmosphere container includes all other layers. BUT, and I agree with you, I
make these layers not overlap by means of appropriate values for heights and
thicknesses.
B.
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Op 14/12/2019 om 10:27 schreef Bruno Cabasson:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> Op 12/12/2019 om 15:25 schreef Bruno Cabasson:
>>> "And" <49341109@ntnu.edu.tw> wrote:
>>>> "Bruno Cabasson" <bru### [at] cabassoncom> wrote:
>>>>>
>>>>> Besides, real atmosphere is a very complex thing, not easy to model, and
>>>>> real clouds are also quite complex and there are many kinds of them, each one
having a specific behaviour with li
> gh
>>> t.
>>>>
>>>>
>>>> In fact, for a fully automatic volumn(cloud) renderer, it is not so different
>>>> between different kind of cloud. The main difference of them is the height, and
>>>> the shape(density map), and the average density(because a dense cloud needs more
>>>> multiple scattering)
>>>>
>>>> ice droplets and liquid water droplets have different phase function when
>>>> scatters light. but for a dense media(if light from sun light source collide
>>>> many times in the cloud) the difference of the final appearance is small.
>>>> And because water droplets almost never absorb light, represent the albedo of
>>>> cloud almost 1.0( between visible wavelength range), so it is seldom eliminated
>>>> in cloud, a light beam can collide hundred of times in a heavy cloud. You can
>>>> see this:
>>>>
http://news.povray.org/povray.binaries.utilities/message/%3Cweb.5bec15ae87bb2a51c8edf6b30%40news.povray.org%3E/#%3
> Cwe
>>> b.
>>>> 5bec15ae87bb2a51c8edf6b30%40news.povray.org%3E
>>>>
>>>> This is the power(sp-radiance) at different level scattering output quantity.
>>>> Maybe you can say the most of it still concentrated at first level. But this is
>>>> an image contains a white cloud on the center, and the blue sky the other. It is
>>>> the average sp-radiance on the whole image. If look at the cloud separately,
>>>> the multiple scattering part is the dominate.
>>>>
>>>> And I attach a comparison. The image contains three images I rendered one year
>>>> ago but should be the same (or similar) condition. They are 1 level, 3 level,
>>>> and 27 level scattering renders.
>>>> (up to down.)
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> "Bruno Cabasson" <bru### [at] cabassoncom> wrote:
>>>>
>>>>> the rest is the same values, except the sun power and the parmeters for the fog
>>>>> media. Colors are obtained automatically thanks to media, mainly the atmosphere
>>>>> with rayleigh scattering.
>>>>>
>>>>> Regards
>>>>
>>>> When I watch this I guess you use scattering "extinction" not 1, because if you
>>>> use correct extinction 1 and lacks of multiple scattering, your clouds
>>>> is impossible so white. finally you use 0.25. When I use POV-Ray rendering
>>>> cloud, I always find I need use filled lights or additional emission.
>>>
>>> Well... The fact is that I used exinction 0.25 for the cloud media for the
>>> renders I posted in this thread. But a value of 1 is supposed to the the only
>>> one realistic. I'll play with this, but I think it will not be dramatic.
>>>
>>> AKAIK, POV-Ray allows you to define several media within the same container
>>> (they add together), and several density functions for each of them (they
>>> multiply together). Therefore, you can complexify and enrich the model that way,
>>> at the expense of render time (and carbon footprint). I'll also play with this.
>>>
>>> interior
>>> {
>>> // Media #1
>>> media
>>> {
>>> <media1 parameters>
>>> density
>>> {
>>> <media1/density1 function>
>>> }
>>> density
>>> {
>>> <media1/density2 function>
>>> }
>>>
>>> .../...
>>>
>>> // Densities are multipled together for the current media
>>> }
>>>
>>> // Media # 2
>>> media
>>> {
>>> <media2 parameters>
>>> density
>>> {
>>> <media2/density1 function>
>>> }
>>> density
>>> {
>>> <media2/density2 function>
>>> }
>>>
>>> .../...
>>>
>>> // Densities are multipled together for the current media
>>> }
>>>
>>> // More media
>>>
>>> .../...
>>>
>>> // Media contributions are added together
>>>
>>> }
>>>
>>> B.
>>>
>>>
>>
>> Something that I do fairly often is to use separate, "layered", media
>> containers, separated by a minimal amount of space. This can be useful
>> e.g. in the case of different cloud layers. This way it is easy to
>> create (1) a water media, over which there is (2) an atmospheric media
>> (fog) with (3 etc) cloud layers above. The fact that the containers do
>> not overlap makes the render faster and avoids mutual media "contamination".
>>
>> --
>> Thomas
>
> Thats'a good thing, to my opinion. I don't really unerstand what you mean by
> media "contamination". Do you mean that there are some issues if the containers
> overlap? For my cloudscape experimental scenes, containers do overlap :
> atmosphere container includes all other layers. BUT, and I agree with you, I
> make these layers not overlap by means of appropriate values for heights and
> thicknesses.
>
> B.
>
>
By "contamination" I mean the influence different media (and their
densities) can have, like in your example where they are added or
multiplied. However, your method with appropriate separate values for
height and thicknesses is equivalent I think. I have used/played with
that recently, and I like it, although I have some trouble to get things
at the correct altitude; mainly a scaling problem I tend to get ensnared
in really. ;-)
--
Thomas
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Your cloud do have some great properties. Although it is unexpected simple(the
pov-code). The fluffy appearance is what I want. And the coverage is moderate.
But in fact the real geometry shows the top and bottom are truncated by the
boundary(800m~1200m). I will think how to solve this in the future, but if you
have idea I think it will be nice.
Post a reply to this message
Attachments:
Download 'bruno cloud 4 sun45 level12 29hr.png' (911 KB)
Preview of image 'bruno cloud 4 sun45 level12 29hr.png'
|
|
| |
| |
|
|
|
|
| |
| |
|
|
This is what I mean.
The program is recommended by Stephan. It can preview the df3 file. But can be
the "emission" style only.
The top and bottom are truncated. Will influence the render effect if care
about.
Post a reply to this message
Attachments:
Download 'shape previewe.png' (478 KB)
Preview of image 'shape previewe.png'
|
|
| |
| |
|
|
|
|
| |
| |
|
|
"And" <49341109@ntnu.edu.tw> wrote:
> Your cloud do have some great properties. Although it is unexpected simple(the
> pov-code). The fluffy appearance is what I want. And the coverage is moderate.
> But in fact the real geometry shows the top and bottom are truncated by the
> boundary(800m~1200m). I will think how to solve this in the future, but if you
> have idea I think it will be nice.
I want to show these pic to you. So I rush for it.
This one is multiple another density factor. 0.18g/m^3, for a wide area cloud
this value is large I read from book. But for cumulus this value is small. It
mean max.
notice the brightness is not the same with the previous
Post a reply to this message
Attachments:
Download 'bruno cloud 3 sun45 level14 1hr.png' (989 KB)
Preview of image 'bruno cloud 3 sun45 level14 1hr.png'
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Op 16/12/2019 om 17:51 schreef And:
> "And" <49341109@ntnu.edu.tw> wrote:
>> Your cloud do have some great properties. Although it is unexpected simple(the
>> pov-code). The fluffy appearance is what I want. And the coverage is moderate.
>> But in fact the real geometry shows the top and bottom are truncated by the
>> boundary(800m~1200m). I will think how to solve this in the future, but if you
>> have idea I think it will be nice.
>
the truncation by the container is indeed a problem I also experience.
Gilles Tran solved this by using df3 as containers. Very effective! See:
http://www.oyonale.com/modeles.php?lang=en&page=36
--
Thomas
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
Thomas de Groot <tho### [at] degrootorg> wrote:
> Op 16/12/2019 om 17:51 schreef And:
> > "And" <49341109@ntnu.edu.tw> wrote:
> >> Your cloud do have some great properties. Although it is unexpected simple(the
> >> pov-code). The fluffy appearance is what I want. And the coverage is moderate.
> >> But in fact the real geometry shows the top and bottom are truncated by the
> >> boundary(800m~1200m). I will think how to solve this in the future, but if you
> >> have idea I think it will be nice.
> >
>
> the truncation by the container is indeed a problem I also experience.
> Gilles Tran solved this by using df3 as containers. Very effective! See:
>
> http://www.oyonale.com/modeles.php?lang=en&page=36
>
> --
> Thomas
I must take a while, but I'm curious how this can avoid that phenomenon.
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
| |
|
|
> Your cloud do have some great properties. Although it is unexpected simple(the
> pov-code). The fluffy appearance is what I want. And the coverage is moderate.
> But in fact the real geometry shows the top and bottom are truncated by the
> boundary(800m~1200m). I will think how to solve this in the future, but if you
> have idea I think it will be nice.
>
You may use a planar pattern to hide that. Just scale and translate it
properly, and add a map or use an alternate wave type to control how it
need to fade near the container's edges.
Post a reply to this message
|
|
| |
| |
|
|
|
|
| |
|
|
