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6 May 2024 16:44:37 EDT (-0400)
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From: clipka
Subject: Re: Shadow on Earth?
Date: 20 Jul 2016 12:27:34
Message: <578fa676$1@news.povray.org>
Am 20.07.2016 um 18:02 schrieb Stephen:

> Besides using an image map. You can add a normal map to give some depth
> and a spectacular map for the seas. You can find some here
> http://planetpixelemporium.com/earth.html

You mean specular, right? ;)

> The atmosphere is always tricky to do and I generally cheat and use a
> cone behind the planet in line with the camera.

I find atmosphere comparatively easy -- as long as I don't try to add
clouds.


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From: Stephen
Subject: Re: Shadow on Earth?
Date: 20 Jul 2016 13:06:07
Message: <578faf7f$1@news.povray.org>
On 7/20/2016 5:27 PM, clipka wrote:
> Am 20.07.2016 um 18:02 schrieb Stephen:
>
>> Besides using an image map. You can add a normal map to give some depth
>> and a spectacular map for the seas. You can find some here
>> http://planetpixelemporium.com/earth.html
>
> You mean specular, right? ;)
>

Who rattled your cage? :P

>> The atmosphere is always tricky to do and I generally cheat and use a
>> cone behind the planet in line with the camera.
>
> I find atmosphere comparatively easy --

Yes you do, don't you. :(

> as long as I don't try to add
> clouds.
>

Clouds are problematic especially in an animation. The simplest way 
would be to use an image map.


-- 

Regards
     Stephen


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From: Kuangy
Subject: Re: Shadow on Earth?
Date: 20 Jul 2016 13:15:01
Message: <web.578fb05180911a1ee6aba5420@news.povray.org>
Mr. clipka,

Thank you for your detailed and useful advice.
Here's the new code I rewrote:

// sunlight
light_source {
 <100, 0, 40>
 color White*100
 parallel
 fade_distance 10
 fade_power 2
 point_at <0, 0, 0>
}

// Earth
sphere {
    <0, 0, 0>, 3.5
    texture {
        pigment {
      image_map {
                jpeg "textures/earth.jpg"
                map_type 1
            }
        }

        finish {
            emission 0.001
            diffuse 0.5
        }

        rotate y*-135
        rotate x*35
    }
    // rotation
    rotate <0, 360*clock, 0>
}

// Earth clouds
difference {
 sphere { <0, 0, 0>, 3.51 }
 sphere { <0, 0, 0>, 3.5 }

 material {
  texture {
   pigment {
    image_map{
     png "textures/earth_cloud.png"
     map_type 1
    }
   }
  }
 }

 hollow on
}

// Earth scattering
difference {
  sphere { <0, 0, 0>, 3.54 }
  sphere { <0, 0, 0>, 3.5 }

  material {
   texture{
   pigment { rgbt 1 }
   }

   interior {
        media {
             scattering {
        5
        color White
        eccentricity 0.56
             }

          density {
         spherical density_map {
    [ 0.0  rgb 0.0 ]
          [ 0.5294*0.25e-6  rgb <0.02, 0.05, 0.2>*0.07 ]
          [ 0.5294*0.4e-6   rgb <0.02, 0.07, 0.3>*0.32 ]
          [ 0.5294*0.5e-6   rgb <0.08, 0.18, 0.4>*0.5 ]
          [ 0.5412*0.6e-6   rgb <0.08, 0.18, 0.4>*0.9 ]
          [ 0.5471*0.65e-6  rgb <0.08, 0.18, 0.4>*1.5 ]
          [ 0.5471*0.675e-6 rgb <0.08, 0.18, 0.4>*4.5 ]
          [ 0.5471*0.71e-6  rgb <0.08, 0.18, 0.4>*12 ]
         }
  scale 3.54
          }
      }
   }
  }

  hollow on
}


And here I attach the brand new rendered image, with clouds added on the
surface.
Thank you very much for your advice.


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Attachments:
Download 'earth.png' (663 KB)

Preview of image 'earth.png'
earth.png


 

From: clipka
Subject: Re: Shadow on Earth?
Date: 20 Jul 2016 13:18:54
Message: <578fb27e$1@news.povray.org>
Am 20.07.2016 um 19:06 schrieb Stephen:
> On 7/20/2016 5:27 PM, clipka wrote:
>> Am 20.07.2016 um 18:02 schrieb Stephen:
>>
>>> Besides using an image map. You can add a normal map to give some depth
>>> and a spectacular map for the seas. You can find some here
>>> http://planetpixelemporium.com/earth.html
>>
>> You mean specular, right? ;)
>>
> 
> Who rattled your cage? :P

OOoooh -- careful! This Code Monkey could accidently type a few lines of
code that make POV-Ray crash specifically on /your/ computer. So stop
talking, human, and hand over the bananas! ;)

>>> The atmosphere is always tricky to do and I generally cheat and use a
>>> cone behind the planet in line with the camera.
>>
>> I find atmosphere comparatively easy --
> 
> Yes you do, don't you. :(
> 
>> as long as I don't try to add
>> clouds.
>>
> 
> Clouds are problematic especially in an animation. The simplest way
> would be to use an image map.

Tried that, and found it looking unconvincing. The best thing I've
managed to come up with so far was a combination of an image map and a
spherical function to create media with a cloud-ish density distribution.

It would be cool if we had a set of cloud image maps epresenting cloud
densities at different altitudes, but I guess such a thing doesn't exist
(yet).


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From: Doctor John
Subject: Re: Shadow on Earth?
Date: 20 Jul 2016 13:20:13
Message: <578fb2cd@news.povray.org>
On 20/07/16 18:09, Kuangy wrote:
> Mr. clipka,
> 
> Thank you for your detailed and useful advice.
> Here's the new code I rewrote:
> 
<snip>
> 
> And here I attach the brand new rendered image, with clouds added on the
> surface.
> Thank you very much for your advice.
> 
 Looking good, Kuangy. If you intend to use this as an animation, don't
forget to rotate the clouds (possibly at a slightly different rate to
the earth).

John
-- 
It's not about bravery.
It's about doing what I need to do to win


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From: clipka
Subject: Re: Shadow on Earth?
Date: 20 Jul 2016 13:21:54
Message: <578fb332$1@news.povray.org>
Am 20.07.2016 um 19:09 schrieb Kuangy:

> And here I attach the brand new rendered image, with clouds added on the
> surface.

Hey, wow -- that actually looks really good.


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From: omniverse
Subject: Re: Shadow on Earth?
Date: 20 Jul 2016 13:55:00
Message: <web.578fbab780911a1eb1933f770@news.povray.org>
Doctor John <j.g### [at] gmailcom> wrote:
> If you intend to use this as an animation, don't
> forget to rotate the clouds (possibly at a slightly different rate to
> the earth).

And spin Earth west to east, note the "-" for that: rotate -360*clock

Unless there's another reason to have the atmosphere not show below Earth's
surface you won't need to use CSG difference, a single sphere alone will be
okay.

I think the answers given already have helped solve the problem.
Texture finish was trouble, as said, and scaling can be done other ways. I would
have began with a sphere {0,1 and then scaled them after image map and media.
Just be aware that media scaled after applied can change the affect,
historically anyway:

sphere {0,1 ... media { ... scale 0.5} scale 10}

Unfortunately I haven't kept up with that subject, I have not done much in
recent years, so please excuse me if media now retains original qualities when
scaling it's containing objects. Maybe it still scales (thickness or thinness).


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From: Stephen
Subject: Re: Shadow on Earth?
Date: 20 Jul 2016 15:41:44
Message: <578fd3f8$1@news.povray.org>
On 7/20/2016 6:18 PM, clipka wrote:
> Am 20.07.2016 um 19:06 schrieb Stephen:

>
> OOoooh -- careful! This Code Monkey could accidently type a few lines of
> code that make POV-Ray crash specifically on /your/ computer. So stop
> talking, human, and hand over the bananas! ;)
>

Interesting that you say that.
When I was working at Taronga Zoo, in Sydney. The keepers in the Monkey 
house used bananas as part of their alarm system. Every night they put a 
banana beside a window. If in the morning the banana was gone. Then the 
monkeys had gotten off of the inner enclosure.


>>
>> Clouds are problematic especially in an animation. The simplest way
>> would be to use an image map.
>
> Tried that, and found it looking unconvincing. The best thing I've
> managed to come up with so far was a combination of an image map and a
> spherical function to create media with a cloud-ish density distribution.
>
> It would be cool if we had a set of cloud image maps epresenting cloud
> densities at different altitudes, but I guess such a thing doesn't exist
> (yet).
>

The big problem that I come up against is that All of these types of 
animations are cyclic and our weather system does show the same behaviour.

-- 

Regards
     Stephen


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From: Alain
Subject: Re: Shadow on Earth?
Date: 21 Jul 2016 16:10:06
Message: <57912c1e@news.povray.org>

> I'm now working hard on my assignment for my CG class at college, in which I'm
> trying to make a realistic earth animation.
> I used "difference" to create something like atmosphere right outside earth, and
> in which I also used emission for making the atmosphere glow. And this is where
> I'm facing a problem.
>
> When I set a light_source from a distance, there is no shadow cast on earth.
> Here I paste the source code:
>
> light_source {
>  <100, 0, 50>
>  color White
>  spotlight
>  fade_distance 100
>  fade_power 10
>  point_at <0, 0, 0>
> }

Why use a spotlight?
Why use fading?

Given the distance from the Sun to the Earth, you are better using a 
parallel light without any fading. Think about it, the Sun-Earth 
distance is over 10000000 times the Earth's radius.
The difference in the illumination over the moon's orbit 's diameter is 
effectively negligible.

fade_power ONLY realistic value is 2.
fade_sidtance should be about the appearent diameter of a light's diameter.
If the light becomes to dark, you can increase it's intensity 
arbitrarily by as much as you need.

Try this one:
light_source{<100, 0, 50>*10 rgb 2 parallel}

>
> // earth
> sphere {
>     <0, 0, 0>, 3.5
>     texture {
>         pigment {
>       image_map {
>                 jpeg "textures/earth.jpg"
>                 map_type 1
>             }
>             scale 3.5

This scalling is useless.

>         }
>
>         finish {
>             ambient 1
>             diffuse 3

Beter use ambient 0, diffuse 0.6 here.
ambient 1 mean that your earth is actualy glowing.
diffuse 3 mean that it give off 3 times as much light as it receive from 
the Sun.

>         }
>
>         rotate y*-135
>         rotate x*35
>     }
>     // rotation
>     rotate <0, 360*clock, 0>
> }
>
> // atmosphere emission
> difference {
>   sphere { <0, 0, 0>, 3.54 }
>   sphere { <0, 0, 0>, 3.0 }
>
>   material {
>    texture{
>    pigment { rgbt 1 }
>    }
>
>    interior {
>      media {
>        emission 0.5

A GLOWING atmosphere? Last time I checked, Earth's atmosphere scatters 
the light and don't emit any.

>        //scattering { 5 color rgb 0.01 eccentricity 0.56 }

The proper model is scattering{4 rgb 0.01}

>        density {
>          spherical density_map {
>        [ 0.0  rgb 0.0 ]
>           [ 0.5294*0.25e-6  rgb <0.02, 0.05, 0.2>*0.07 ]
>           [ 0.5294*0.4e-6   rgb <0.02, 0.07, 0.3>*0.32 ]
>           [ 0.5294*0.5e-6   rgb <0.08, 0.18, 0.4>*0.5 ]
>           [ 0.5412*0.6e-6   rgb <0.08, 0.18, 0.4>*0.9 ]
>           [ 0.5471*0.65e-6  rgb <0.08, 0.18, 0.4>*1.5 ]
>           [ 0.5471*0.675e-6 rgb <0.08, 0.18, 0.4>*4.5 ]
>           [ 0.5471*0.71e-6  rgb <0.08, 0.18, 0.4>*12 ]
>          }
>      scale 100
>        }
>      }
>    }
>   }
>
>   hollow on
> }
>
> And below I attach the rendered result for now.
>
> How can I solve this problem? I'd appreciate it if someone could help.
> I'm not a native English speaker, so I'm very sorry for my poor English... I
> really wish I didn't use impolite expressions!
>
> Thanks.
>

Alain


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From: Cousin Ricky
Subject: Re: Shadow on Earth?
Date: 23 Jul 2016 01:00:01
Message: <web.5792f99980911a1eb484452a0@news.povray.org>
Alain <kua### [at] videotronca> wrote:
>  Think about it, the Sun-Earth
> distance is over 10000000 times the Earth's radius.

I get 23481 times, a far cry from 10 million.


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