I have started to work on your scene, to adapt it even more.

Yes, you are right - changing the atmospheric colors does not lead to
straight, expected results, but to unexpectable new colors. I believe
(but I have no clue about media and density), that the reason for this
color problem lays with the fact, that you specify the colors within the
density map. I wonder, if there is a way to use neutral shades for the
density map, and move the color map into the pigment statement right
below the coordinates of the cloud layer.

Also, seeing that the horizon is too curvy, I try out using a box
instead of a cylinder for the cloud layer. I now use the keyword "boxed"
for "density" instead"spherical", but the horizon still looks like that
of a cylinder. Can you advise? See my altered source code below.

Once I got the environment right, then I will work on the architecture
of the skyscrapers. I have some weird visions... :-D

Basically, the task is now to get the horizon straight, and then to find
a way to change the colors the way we want.

UPDATE
Horizon okay now.
I wonder, if I can use these two suns as light sources instead of a
traditional light_source, when filling them with media?

------------------



---

http://www.avg.com

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Attachments:
Download 'sl - cloud cities - omniverse - 02.jpg' (90 KB)

Preview of image 'sl - cloud cities - omniverse - 02.jpg'

CODE

--------------------------

#version 3.8;

#declare MyRadiosity = on;

global_settings
{
 assumed_gamma 1.4
 #if(MyRadiosity=on)
  radiosity { media on }
 #end
}

#default
{
 finish { ambient 0.0 diffuse 1.0 }
}

//------------------------------------------------------------------------
#include "colors.inc"
#include "textures.inc"
#include "glass.inc"
#include "metals.inc"
#include "golds.inc"
//------------------------------------------------------------------------

camera
{
 /*ultra_wide_angle*/ //angle 20
 location  < -35.0 , 11.0 , 0.0 >
 //right     x*image_width/image_height // not needed for v3.8
 look_at   < 0.0 , 5.0 , 0.0 >
}

// sun -------------------------------------------------------------------
light_source
{
 -z*9999.0//< 50, 100, -250 >*10e4
 color 1.0 * 1.4//< 1.0,  0.62353,  0.46667 >*2
 rotate < 20.0, 240.0, 0.0 > // altitude, azimuth, tilt
}

// sky -------------------------------------------------------------------
background { color rgb 0.0 }

disc
{
 0.0, y, 1.0, 0.0
 hollow on
 no_shadow
 pigment { rgb < 0.5, 0.75, 1.0 > }
 scale 100.0
 translate y*100.0
}

// ground -----------------------------------------------------------------


box
{
 < -1.0, -1.0, -1.0 > < 1.0, 1.0, 1.0 >
 pigment { color rgb 1.0 }
 scale < 555.0, 497.0, 555.0 >
 translate -y*494.0
}

//-------------------------------------------------------------------------
-
// Clouds
#local Scale = 5.0;

#declare Clouds = density
{
 ripples   // controls the cloud formation
 color_map
 {
  [ 0.33 rgb  10.0 ]
  [ 0.67 rgb 100.0 ]
 }
 scale < 3.0, 1.0, 10.0 >*0.5
 warp { turbulence < 2.5, 1.0, 1.6 > }
 rotate 45.0*y
}

//cloud layer:
box
{
 < -1.0, -1.0, -1.0 > < 1.0, 1.0, 1.0 >
 pigment { rgbt 1.0 }
 hollow
 interior
 {
  media
  {
   samples 20
   absorption < 3.0, 4.0, 0.5 >*1.0/(Scale*100.0)
   emission   < 1.0, 1.0, 1.0 >*0.5/(Scale*100.0)
   scattering
   {
    1
    < 0.5, 0.75, 1.5 >*3.0/(Scale*100.0)
    extinction 0.5
   }
   density
   {
    boxed
    density_map
    {
     [ 0.000 rgb 0.0 ]
     [ 0.001 Clouds scale 1.0/100.0 ]
    }
   }
  }
 }
 scale Scale*100.0
 translate -y*494.0
}

//-------------------------------------------------------------
//atmosphere:
sphere
{
 < 0.0, 0.0, 0.0 >, 1.0
 pigment { rgbt 1.0 }
 hollow
 interior
 {
  media
  {
   samples 20
   absorption 0.5
   scattering
   {
    5
    < 1.25, 1.0, 1.5 >*2.0/Scale
    extinction 0.67
    eccentricity 0.2
   }
   density
   {
    gradient y
    color_map
    {
/*
     [ 0.00 rgb 1.0 ]  //base ground fog
     [ 0.10 rgb < 9.0, 0.3, 0.10 > ]  //top ground fog
     [ 0.30 rgb < 0.9, 0.3, 0.10 > ]  //top ground fog
     [ 0.50 rgb < 0.5, 0.1, 0.09 >*0.100 ] //base atmospheric haze
     [ 0.67 rgb < 0.1, 0.2, 0.90 >*0.100 ] //top atmospheric haze
     [ 1.00 rgb < 0.1, 0.3, 0.90 >*0.001 ] //top atmospheric haze
*/
     [ 0.00 rgb < 1.0, 1.0, 1.00 >*1.000 ] //base ground fog
     [ 0.10 rgb < 3.0, 0.3, 0.10 >*1.000 ] //top ground fog
     [ 0.30 rgb < 0.3, 0.3, 0.10 >*1.000 ] //top ground fog
     [ 0.50 rgb < 0.5, 0.1, 0.09 >*0.100 ] //base atmospheric haze
     [ 0.67 rgb < 0.3, 0.7, 1.00 >*0.100 ] //top atmospheric haze
     [ 1.00 rgb < 0.3, 0.7, 1.00 >*0.001 ] //top atmospheric haze
    }
    rotate -x*15.0
    warp { spherical }
    scale Scale*2.0*y
   }
  }
 }
 scale Scale*111.0
 translate -y*535.0
}


//-------------------------------------------------------------
// Planet:

union
{
 sphere
 {
  < 0.0, 0.0, 0.0 > 7.0
  pigment
  {
   gradient y
   color_map
   {
    [ 0.00 rgb < 1.0, 1.0, 1.0 >*0.25 ]
    [ 0.10 rgb < 1.0, 1.0, 1.0 >*0.25 ]
    [ 0.12 rgb < 1.0, 1.0, 1.0 >*0.25 ]
    [ 0.15 rgb < 0.80392, 0.66275, 0.47059 >*0.25 ]
    [ 0.20 rgb < 0.80392, 0.66275, 0.47059 >*0.25 ]
    [ 0.22 rgb < 0.63922, 0.55686, 0.31373 >*0.25 ]
    [ 0.27 rgb < 0.63922, 0.55686, 0.31373 >*0.25 ]
    [ 0.40 rgb < 0.47451, 0.30980, 0.14118 >*0.25 ]
    [ 0.43 rgb < 0.47451, 0.30980, 0.14118 >*0.25 ]
    [ 0.45 rgb < 0.20392, 0.24314, 0.41176 >*0.25 ]
    [ 0.55 rgb < 0.20392, 0.24314, 0.41176 >*0.25 ]
    [ 0.57 rgb < 0.47451, 0.30980, 0.14118 >*0.25 ]
    [ 0.60 rgb < 0.47451, 0.30980, 0.14118 >*0.25 ]
    [ 0.73 rgb < 0.63922, 0.55686, 0.31373 >*0.25 ]
    [ 0.78 rgb < 0.63922, 0.55686, 0.31373 >*0.25 ]
    [ 0.80 rgb < 0.80392, 0.66275, 0.47059 >*0.25 ]
    [ 0.85 rgb < 0.80392, 0.66275, 0.47059 >*0.25 ]
    [ 0.88 rgb < 1.0, 1.0, 1.0 >*0.25 ]
    [ 0.90 rgb < 1.0, 1.0, 1.0 >*0.25 ]
    [ 1.00 rgb < 1.0, 1.0, 1.0 >*0.25 ]
   }
   turbulence 0.3
   translate < 0.0, -7.0, 0.0 >
   scale 14.0
  }
 }
 difference
 {
  cylinder { < 0.0, -0.00001, 0.0 > < 0.0, 0.00001, 0.0 > 16.0 }
  cylinder { < 0.0, -0.00002, 0.0 > < 0.0, 0.00002, 0.0 > 10.0 }
  pigment
  {
   onion
   color_map
   {
    [ 0.00 rgb < 0.47451, 0.30980, 0.14118 > ]
    [ 0.60 rgb < 0.47451, 0.30980, 0.14118 > ]
    [ 0.62 rgb < 0.47451, 0.30980, 0.14118 > ]
    [ 0.63 rgb < 0.80392, 0.66275, 0.47059 > ]
    [ 0.66 rgb < 0.80392, 0.66275, 0.47059 > ]
    [ 0.67 rgb < 0.63922, 0.55686, 0.31373 > ]
    [ 0.71 rgb < 0.63922, 0.55686, 0.31373 > ]
    [ 0.73 rgb < 0.47451, 0.30980, 0.14118 > ]
    [ 0.76 rgb < 0.47451, 0.30980, 0.14118 > ]
    [ 0.80 rgb < 0.63922, 0.55686, 0.31373 > ]
    [ 0.81 rgb < 0.63922, 0.55686, 0.31373 > ]
    [ 0.82 rgb < 0.47451, 0.30980, 0.14118 > ]
    [ 0.83 rgb < 0.47451, 0.30980, 0.14118 > ]
    [ 0.86 rgb < 0.63922, 0.55686, 0.31373 > ]
    [ 0.88 rgb < 0.63922, 0.55686, 0.31373 > ]
    [ 0.89 rgb < 0.80392, 0.66275, 0.47059 > ]
    [ 0.91 rgb < 0.80392, 0.66275, 0.47059 > ]
    [ 0.97 rgb < 0.63922, 0.55686, 0.31373 > ]
    [ 0.99 rgb < 0.63922, 0.55686, 0.31373 > ]
    [ 1.00 rgb < 0.63922, 0.55686, 0.31373 > ]
   }
   scale 16.0
  }
  finish { crand 1.0 emission 0.1 }
 }
 scale 250.0
 rotate < -10.0, -20.0, 50.0 >
 translate < 160.0, 50.0, -100.0 >*33.0
}

// Big Sun
sphere
{
 < 0.0, 0.0, 0.0 > 1.0
 pigment
 {
  gradient y
  color_map
  {
   [ 0.00 rgb < 0.0, 0.0, 0.0 > ]
   [ 0.50 rgb < 0.0, 0.0, 0.0 > ]
   [ 1.00 rgb < 3.0, 0.0, 0.1 >*5.0 ]
  }
  translate < 0.0, -0.5, 0.0 >
  scale 2.0
 }
 finish { emission 1.0 }
 scale 12.0
 scale 33.0
 translate < 80.0, -0.0, 35.0 >*33.0
}
// Small Sun
sphere
{
 < 0.0, 0.0, 0.0 > 1.0
 pigment { color rgb < 0.1, 0.3, 20.0 >*10.0 }
 finish { emission 2.0 }
 scale 33.0
 translate < 80.0, 12.0, 46.0 >*33.0
}

//-------------------------------------------------------------
//artefact:
#local S=seed(4132);
union
{
 #for (It,1.0,8.0,1.0)

  #local xR=rand(S);
  #local yR=rand(S);
  #local zR=rand(S);

  #local xR2=rand(S);
  #local yR2=rand(S);
  #local zR2=rand(S);

  box
  {
   0.0, 1.0
   scale < 1.0+xR, 8.0+yR*4, 1.0+zR >/2.0
   pigment
   {
    checker
    color rgb 0.1 color rgb 0.9 scale 0.5
   }
   translate (-< xR*20.0,0.0,zR*20.0 > + <xR2*40.0, 0.0, zR2*40.0 >)/2.0
  }
 #end
 rotate y*90.0
 translate < -20.0, 2.0, 5.0 >
}

---

http://www.avg.com

Post a reply to this message

On 28/11/2017 11:31, Sven Littkowski wrote:
> Yes, you are right - changing the atmospheric colors does not lead to
> straight, expected results, but to unexpectable new colors. I believe
> (but I have no clue about media and density), that the reason for this
> color problem lays with the fact, that you specify the colors within the
> density map. 

No, The density map is not for the colour. The colour comes from the 
media setting.
The density map is used by Pov as a pattern to calculate the density 
through the volume of the media.

> I wonder, if there is a way to use neutral shades for the
> density map, 

This is where you are going wrong. You are thinking of the density map 
as a colour map.

> and move the color map into the pigment statement right
> below the coordinates of the cloud layer.

The pigment should be 100% transparent so effectively it has no colour.

I see that in the code I posted I had used a small amount of absorption. 
I was an egg and thought that it would obscure the dancer's feet a bit.
I used a little emission to give the cloud a slightly glowing effect. 
(It was a dream sequence after all.)

-- 

Regards
     Stephen

Post a reply to this message

On 28-11-2017 12:28, Bald Eagle wrote:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> However, clouds by
>> themselves are always white/grey (water vapour, remember?). Adding
>> colour makes no sense,
> 
> I'd say to be entirely acurate, clouds themselves are colorless, or even more
> accurately - reflect the colors surrounding them.
> The tiny water droplets are clear, as are polar bear hairs, but due to the
> extreme curvature, reflect light back toward the viewer, refract the light, due
> to the ior, and scatter it.
> Rainbows are just lit-up water vapor (and are circular).
> 
> I have, for the past year taken much more notice of things "out there" IRL, and
> the clouds are almost _never_ white/grey - they are all manner of pink and
> purple, and orange, red and bluish-gray....
> It depends on the time of day.

Absolutely! Sunlight is a great painter! :-)

> 
> Just nitpicking, and "keeping it real".   ;)
> 

and a welcome thing. ;-)


-- 
Thomas

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There's a lot of stuff to comment on, and little time to do it.
Truly, you need to stop randomly changing things without understanding what they
do and how they do it (if your goal is a targeted result).
That, and F1 is your friend.

boxed is a POV-Ray pattern, not a container shape.

> //atmosphere:
> sphere
this is why the horizon is sharply curved.   Change the radius to something
bigger, and move the center to compensate.

>     gradient y

This is why the colors change in a non-intuitive way.
You have a spherical container, but a flat gradient y.
Use a spherical pattern instead of gradient. (think center-out, not bottom to
top)


This is indeed working out to be a beautiful scene.

Will there be a large Roman ship with oars dipping into the clouds?   ;)

Post a reply to this message

"Bald Eagle" <cre### [at] netscapenet> wrote:

> Use a spherical pattern instead of gradient. (think center-out, not bottom to
> top)

.... and just to clarify, by "spherical" I mean pigment {onion ...}

http://wiki.povray.org/content/Reference:Onion_Pattern

Post a reply to this message

Sven Littkowski <I### [at] SvenLittkowskiname> wrote:
>
> global_settings
> {
>  assumed_gamma 1.4

Ah yes, that was one of the other things I should have told you about.

I only replaced 1.0 with 1.4 to artificially darken the image because I wasn't
getting a dark enough orange haze layer in the sky any other way.

You will not want to use anything other than 1.0 there, adjust scene elements
themselves instead.

Not sure without checking first but maybe replace rgb colors with srgb?

I will defer to advise being given from other people here, they've been doing
good already. I probably should have written scene comments as a guide but I was
being too quick making changes without thinking it over.

Bob

Post a reply to this message

On 28.11.2017 07:48, Bald Eagle wrote:
> There's a lot of stuff to comment on, and little time to do it.
> Truly, you need to stop randomly changing things without understanding what they
> do and how they do it (if your goal is a targeted result).
> That, and F1 is your friend.

Not with Povray v3.8 - it seems no help is yet linked to F1 and
keywords. Of course, I had tried...   :-(

> boxed is a POV-Ray pattern, not a container shape.

Ohhh. Thanks.

>> //atmosphere:
>> sphere
> this is why the horizon is sharply curved.   Change the radius to something
> bigger, and move the center to compensate.
> 
>>     gradient y
> 
> This is why the colors change in a non-intuitive way.
> You have a spherical container, but a flat gradient y.
> Use a spherical pattern instead of gradient. (think center-out, not bottom to
> top)

I want to transform the two suns into light-giving media (no clue how)
and then to remove the existing traditional light_source. Help needed.

Spherical pattern: onion?

> This is indeed working out to be a beautiful scene.
> 
> Will there be a large Roman ship with oars dipping into the clouds?   ;)

No, not a Roman ship. But there will be futuristic skyscrapers and
flying apartments (round flattened bubbles) that can dock to the tall
buildings in swarms, or hover around slowly above or below the clouds.

I want to make the scene public domain, and then invite everyone to join
with their own skyscrapers.


---

http://www.avg.com

Post a reply to this message

On 28.11.2017 10:03, Bald Eagle wrote:
> .... and just to clarify, by "spherical" I mean pigment {onion ...}

Yes, got it. Using it for the rings already. :-)


---

http://www.avg.com

Post a reply to this message

On 28.11.2017 10:54, omniverse wrote:
> Sven Littkowski <I### [at] SvenLittkowskiname> wrote:
>>
>> global_settings
>> {
>>  assumed_gamma 1.4
> 
> Ah yes, that was one of the other things I should have told you about.
> 
> I only replaced 1.0 with 1.4 to artificially darken the image because I w
asn't
> getting a dark enough orange haze layer in the sky any other way.
> 
> You will not want to use anything other than 1.0 there, adjust scene elem
ents
> themselves instead.
> 
> Not sure without checking first but maybe replace rgb colors with srgb?
> 
> I will defer to advise being given from other people here, they've been d
oing
> good already. I probably should have written scene comments as a guide bu
t I was
> being too quick making changes without thinking it over.
> 
> Bob
> 

In any way, your help is tremendous! And highly appreciated!

I want to change the two suns into light-emitting media, can you assist?
I simply lack expertise, never worked with media. Those will later
replace the traditional light_source.

Hazes can be done by the onion-pattern instead of Y-oriented color_map,
a suggestion by other members is.

I am happy with 1.0 *1.4 light, it looks very good.

---

http://www.avg.com

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