So, after I modified the clouds inside the worldbowl to
be made of media-density (which resulted in a need to
combine atmospherical effects and clouds into one
container to work properly), I've found that the nice shadow-
lines the clouds leave in the atmosphere disappeared...

Obviously, the scattering media of the clouds behaved
differently than the stacked-discs-method I used before,
so I kept wondering how I might darken the shadows, but
keep the clouds with the same brightness...

Its the first time I actually use all three media-types,
scattering for the obvious scattering, absorption to make
them appear more dense and to kill light inside the
clouds, and emission to brighten them up after the absorption
swallowed tons of light.

I guess I could go for even more contrast with shadows
in the atmosphere, but to exagerate wouldn't be my style. I'm
still pondering about a little more or less absorption, and the
brightness of the clouds, but I'm satisfied that I achieved
what I intended. Learned a lot about media this way...

Anyways, enjoy!


--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html
Email: Tim### [at] gmxde

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Attachments:
Download 'media_change.jpg' (29 KB)

Preview of image 'media_change.jpg'

This has been a very neat project to watch.

Have you used media_attenuation in the light source?

I'm thinking your only other chance to refine those cloud shadows is to
sharpen the boundary line of density that goes from high rgb to low (or
none). Which could mean using an element in the density map which is very
thick and surround that with the regular entries but very near to it. I
couldn't say if that will really look okay or not, just an idea.

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"Tim Nikias" <tim### [at] gmxde> wrote in message
news:3e46e74b@news.povray.org...

   Very nice Tim. I too, have been following this. I can't comment on
your media hassles, but I would like to say that something else has to
(hopefully) be added to your WorldBowl in the future - maybe birds,
some dark, and some light, (to reflect that moon or lamp). An
aeroplane? A couple of miniature ships/liners too?

   That WorlBowl is a picture on its own and the clouds are great imo.
:)

   ~Steve~



> Tim Nikias
> Homepage: http://www.digitaltwilight.de/no_lights/index.html
> Email: Tim### [at] gmxde

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Thanks for the praise! But I don't get what you're
trying to tell me with
"maybe birds, some dark, and some light, (to reflect that
moon or lamp)".
Do you mean dark and light birds in terms of color, or
something entirely different (like dark birds, but something
smaller which also sheds light into the worldbowl, like a house
with glowing windows or such)?

The problem about the objects that might be put into the
worldbowl is the scale. For one, the scale inside is just
extreme, if you look at the snow-covered peaks of the
mountains, an actual aeroplane would probably be only
about two or maximum of 3 pixels large.
Perhaps I'll have to change the scale of the mountains,
especially their steepness and the texturing, to get a smaller
scale, and then create some huts or such...
I kinda like the idea of some small campfire with a little
smoketrail (media, of course). Though its broad daylight inside
the bowl... Hm. Got to give it some more thought.

Regards,
Tim

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html
Email: Tim### [at] gmxde

>
>    Very nice Tim. I too, have been following this. I can't comment on
> your media hassles, but I would like to say that something else has to
> (hopefully) be added to your WorldBowl in the future - maybe birds,
> some dark, and some light, (to reflect that moon or lamp). An
> aeroplane? A couple of miniature ships/liners too?
>
>    That WorlBowl is a picture on its own and the clouds are great imo.
> :)
>
>    ~Steve~
>
>
>

Post a reply to this message

> This has been a very neat project to watch.
Thanks.

> Have you used media_attenuation in the light source?
Sure, how else would media interact with lights? But actually,
its the other way round: those lightsources that shouldn't
affect the bowl have media-attenuation off
(which works quiet well even with the moonlight, cause
the outside clouds are still stacked-planes, wanted to keep
some tradition in the image).

> I'm thinking your only other chance to refine those cloud shadows is to
> sharpen the boundary line of density that goes from high rgb to low (or
> none). Which could mean using an element in the density map which is very
> thick and surround that with the regular entries but very near to it. I
> couldn't say if that will really look okay or not, just an idea.

It already is a pretty sharp contrast going from no density (rgb 0) to
some density (rgb something), as I actually wanted to have the
clouds look a little brushed out. I'm thinking about given them
some shearing effect, to simulate some sort of wind.
Also, I've noticed I could raise absorption and emission some more,
which would enhance the shadowing effect some more. I don't want
true sharp shadowlines, but a little more effect might be nice.


--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html
Email: Tim### [at] gmxde

Post a reply to this message

"Tim Nikias" <tim### [at] gmxde> wrote in message
news:3e480893@news.povray.org...
> Thanks for the praise! But I don't get what you're
> trying to tell me with
> "maybe birds, some dark, and some light, (to reflect that
> moon or lamp)".
> Do you mean dark and light birds in terms of color, or
> something entirely different (like dark birds, but something
> smaller which also sheds light into the worldbowl, like a house
> with glowing windows or such)?

      Sorry, thought you might have got it. Birds have an irridescence
in/on their feathers, so if you had some very small birds in there
fluttering(?!) around, some of them would reflect light and some
wouldn't, depending on their angle to the light-source. Although, some
birds don't have to be small, they could be quite large (in a
WorldBowl sort of way)  ;) as in closer to the viewer, and with flying
birds, you only have to do a small V or M shape... I think it would
work.

>
> The problem about the objects that might be put into the
> worldbowl is the scale. For one, the scale inside is just
> extreme, if you look at the snow-covered peaks of the
> mountains, an actual aeroplane would probably be only
> about two or maximum of 3 pixels large.
> Perhaps I'll have to change the scale of the mountains,
> especially their steepness and the texturing, to get a smaller
> scale, and then create some huts or such...
> I kinda like the idea of some small campfire with a little
> smoketrail (media, of course). Though its broad daylight inside
> the bowl... Hm. Got to give it some more thought.

     Yes, I understand, and nice idea. Basically, all I'm saying is
that something should be added that associates a little more with a
'World' as we know it imo (if that's what you're after), and this is
limitless... I thought about a 'plane, but yes, probably too small to
recognise, whereas I can just see a small ship in the sea with a
smoking funnel... (bigger than a plane in real terms of course).

   A volcano in the far distance might work too... Just some ideas.
It's looking good. :)

   ~Steve~


>
> Regards,
> Tim
>
> --
> Tim Nikias
> Homepage: http://www.digitaltwilight.de/no_lights/index.html
> Email: Tim### [at] gmxde
>
> >
> >    Very nice Tim. I too, have been following this. I can't comment
on
> > your media hassles, but I would like to say that something else
has to
> > (hopefully) be added to your WorldBowl in the future - maybe
birds,
> > some dark, and some light, (to reflect that moon or lamp). An
> > aeroplane? A couple of miniature ships/liners too?
> >
> >    That WorlBowl is a picture on its own and the clouds are great
imo.
> > :)
> >
> >    ~Steve~
> >
> >
> >
>
>

Post a reply to this message

"Tim Nikias" <tim### [at] gmxde> wrote in message
news:3e4809ac@news.povray.org...
>
> > Have you used media_attenuation in the light source?
> Sure, how else would media interact with lights?

media_attenuation, not media_interaction which is already used by default.
Attenuation so the light falls off with distance through the media. I wasn't
sure if you had already used both those keywords in the light_source.
However, now I'm thinking it might affect the entire media object instead of
only where the clouds appear. I say that because I just checked on that by
using a cloud animation I was trying out after someone had asked about a
fly-thru of clouds.

What I was suggesting about the density before would probably go like this:

        [0.50 rgb 0.0]
        [0.50 rgb 0.25]
        [0.55 rgb 3.0] // whatever is best for this part, a shell effect
        [0.60 rgb 0.5]
        [1.00 rgb 1.0]

But not having tried it I couldn't say it is right.

Post a reply to this message

Hm. No, I didn't use media_attenuation, but I just tried
it with using it, and to be honest, I see no significant change,
other than tracing slower. I wasn't sure what to expect though,
after all, I'm using scattering media, which absorbs light, so
how should there be much difference? I don't understand the
keyword really, at least not what it implies on using with media
(I do get it if its required for fog), other than doing something which
the media already does itself: swallow some light.

About your shell-idea: I think that'll result with some strange
shadows: where parts of the shell overlap (shadow-wise speaking),
the shadow will be really dark, but when passing right through the
middle of such a bubble, it will be brighter than the shadowrim.
When I have the time, I'll fiddle with it, but I thank for realism's sake
I should stick with the approach I'm using right now. I've gotten used
to it, at least in this image.

But I'll experiment with it using a sphere, scattering media etc, just to
see the effect.

Regards,
Tim

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html
Email: Tim### [at] gmxde

> >
> > > Have you used media_attenuation in the light source?
> > Sure, how else would media interact with lights?
>
> media_attenuation, not media_interaction which is already used by default.
> Attenuation so the light falls off with distance through the media. I wasn't
> sure if you had already used both those keywords in the light_source.
> However, now I'm thinking it might affect the entire media object instead of
> only where the clouds appear. I say that because I just checked on that by
> using a cloud animation I was trying out after someone had asked about a
> fly-thru of clouds.
>
> What I was suggesting about the density before would probably go like this:
>
>         [0.50 rgb 0.0]
>         [0.50 rgb 0.25]
>         [0.55 rgb 3.0] // whatever is best for this part, a shell effect
>         [0.60 rgb 0.5]
>         [1.00 rgb 1.0]
>
> But not having tried it I couldn't say it is right.
>
>

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Tim,

first of all, I really like your project although I haven't followed
it too closely. In particular, I like the last addition.

St. wrote:
>>
>> The problem about the objects that might be put into the
>> worldbowl is the scale. For one, the scale inside is just
>> extreme, if you look at the snow-covered peaks of the
>> mountains, an actual aeroplane would probably be only
>> about two or maximum of 3 pixels large.
>> Perhaps I'll have to change the scale of the mountains,
>> especially their steepness and the texturing, to get a smaller
>> scale, and then create some huts or such...
>> I kinda like the idea of some small campfire with a little
>> smoketrail (media, of course). Though its broad daylight inside
>> the bowl... Hm. Got to give it some more thought.
> 
>      Yes, I understand, and nice idea. Basically, all I'm saying is
> that something should be added that associates a little more with a
> 'World' as we know it imo (if that's what you're after), and this is
> limitless... I thought about a 'plane, but yes, probably too small to
> recognise, whereas I can just see a small ship in the sea with a
> smoking funnel... (bigger than a plane in real terms of course).

I agree with St. that some live sign(s) would add to this scene. 
I thought of a sailing ship and/or a (light) house. Something very
small that you can only recognize if you look close enough.

Happy tracing
Thomas

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I had thought about a lighthouse in the early concepts
for Worldbowl, way back in 2002 (ehm, well, thats not
really way back, is it? Depends...) I'll guess I'll return to
that, cause it is the only housing (aside of little huts with
straw-roofs) I can imagine for this...

wouldn't it? Might fit nontheless.
I'll give the lighthouse a go...

Tim

--
Tim Nikias
Homepage: http://www.digitaltwilight.de/no_lights/index.html
Email: Tim### [at] gmxde

>
> Tim,
>
> first of all, I really like your project although I haven't followed
> it too closely. In particular, I like the last addition.
>
snip
>
> I agree with St. that some live sign(s) would add to this scene.
> I thought of a sailing ship and/or a (light) house. Something very
> small that you can only recognize if you look close enough.
>
> Happy tracing
> Thomas

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