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From: Jaime Vives Piqueres
Subject: concentric blobs clouds
Date: 26 Apr 2016 08:47:12
Message: <571f6350@news.povray.org>
I was going to add some cumulus to my sea scene, but the ones I had from
the project tierra where not very convincing, so... I started another
experiment.

The approach is similar to that of my previous cumulus include, but with
a trick to make softer media. As the method involved the object pattern,
the media was a bit sharp with just 0 or 1 in the density map.

The trick is to create an array of blob components positions and radius,
then use that to create 4 blobs with concentric shapes and use them on
an averaged density map. The results are surprisingly fast... this one
took "only" 47 min.

--
jaime


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Attachments:
Download 'blob-clouds-test-03d.jpg' (52 KB)

Preview of image 'blob-clouds-test-03d.jpg'
blob-clouds-test-03d.jpg


 

From: Norbert Kern
Subject: Re: concentric blobs clouds
Date: 26 Apr 2016 09:05:01
Message: <web.571f66e85193772e670f6e990@news.povray.org>
Jaime Vives Piqueres <jai### [at] ignoranciaorg> wrote:

> The trick is to create an array of blob components positions and radius,
> then use that to create 4 blobs with concentric shapes and use them on
> an averaged density map. The results are surprisingly fast... this one
> took "only" 47 min.

Nice and fluffy as it should be.

The method of averaging object patterns will be of further use - at least I hope
so...

Norbert


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From: And
Subject: Re: concentric blobs clouds
Date: 26 Apr 2016 09:45:00
Message: <web.571f70925193772eff125f370@news.povray.org>
Jaime Vives Piqueres <jai### [at] ignoranciaorg> wrote:
> I was going to add some cumulus to my sea scene, but the ones I had from
> the project tierra where not very convincing, so... I started another
> experiment.
>
> The approach is similar to that of my previous cumulus include, but with
> a trick to make softer media. As the method involved the object pattern,
> the media was a bit sharp with just 0 or 1 in the density map.
>
> The trick is to create an array of blob components positions and radius,
> then use that to create 4 blobs with concentric shapes and use them on
> an averaged density map. The results are surprisingly fast... this one
> took "only" 47 min.
>
> --
> jaime

Here is a resource about the simulation on cloud phenomenon which I know.

http://wiki.flightgear.org/Atmospheric_light_scattering


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From: William F Pokorny
Subject: Re: concentric blobs clouds
Date: 26 Apr 2016 09:52:49
Message: <571f72b1$1@news.povray.org>
On 04/26/2016 08:47 AM, Jaime Vives Piqueres wrote:
> I was going to add some cumulus to my sea scene, but the ones I had from
> the project tierra where not very convincing, so... I started another
> experiment.
>
> The approach is similar to that of my previous cumulus include, but with
> a trick to make softer media. As the method involved the object pattern,
> the media was a bit sharp with just 0 or 1 in the density map.
>
> The trick is to create an array of blob components positions and radius,
> then use that to create 4 blobs with concentric shapes and use them on
> an averaged density map. The results are surprisingly fast... this one
> took "only" 47 min.
>
> --
> jaime
>
Impressive - though am I correct there are some artifacts in the right 
part of the center top plume? Was it run with AA ?

Asking mostly because of my continuing look into blob related bugs.Those 
spots look like other issues I have seen related to media and blobs at 
the blob(s) boundary.

Bill P.


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From: Jaime Vives Piqueres
Subject: Re: concentric blobs clouds
Date: 26 Apr 2016 12:39:55
Message: <571f99db$1@news.povray.org>

> Nice and fluffy as it should be.

   Thanks... perhaps too fluffy, tough.

> The method of averaging object patterns will be of further use - at least I hope
> so...

  Well, it's nothing fancy, just the average pattern. The real trick is
that the averaged blobs are concentric (with diminishing radius and the
same threshold):


   interior{
     media{
       method 3 intervals 1 samples Cloud_Samples
       scattering{2,.01}
       absorption .005
       density{
         average
         density_map{
           [1
             object{
               cloud_a
               color rgb 0
               color rgb .25
             }
             warp{turbulence .5}
             scale 2 warp{turbulence .67} scale 1/2
             scale 4 warp{turbulence 1} scale 1/4
           ]
           [1
             object{
               cloud_b
               color rgb 0
               color rgb .5
             }
             warp{turbulence .5}
             scale 2 warp{turbulence .67} scale 1/2
           ]
           [1
             object{
               cloud_c
               color rgb 0
               color rgb .75
             }
             warp{turbulence .5}
           ]
           [1
             object{
               cloud_d
               color rgb 0
               color rgb 1
             }
             warp{turbulence .5}
           ]
         }
       }
     }
   }

--
jaime


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From: Jaime Vives Piqueres
Subject: Re: concentric blobs clouds
Date: 26 Apr 2016 12:45:55
Message: <571f9b43@news.povray.org>

> Here is a resource about the simulation on cloud phenomenon which I
> know.
>
> http://wiki.flightgear.org/Atmospheric_light_scattering

   Well, fortunately POV-Ray media scattering type 2 takes care of all
that... what I'm really looking for is some method to create convincing
cumulus shapes. Right now they are just a bunch of blob spheres filling
a random conical shape, but I've got some ideas to try from this paper:

   https://hal.inria.fr/inria-00537462/file/BN04_clouds.pdf

   I will try to start with a base blob with just a few big components
and then trace a lot of smaller ones on the surface of it.

--
jaime


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From: Jaime Vives Piqueres
Subject: Re: concentric blobs clouds
Date: 26 Apr 2016 12:56:13
Message: <571f9dad@news.povray.org>
El 26/04/16 a las 15:52, William F Pokorny escribió:
> Impressive - though am I correct there are some artifacts in the
> right part of the center top plume? Was it run with AA ?

   You have a good eye... I had to zoom several times to see them! Yes,
it was run without AA, and the artifacts are likely due to the media
container (another blob, BTW... I forgot to mention this).

> Asking mostly because of my continuing look into blob related
> bugs.Those spots look like other issues I have seen related to media
> and blobs at the blob(s) boundary.

   Yes, that's likely the problem: see the attached test. The inner solid
blob is the object used on the density pattern, and the transparent
outer blob is the media container: you can clearly see the artifacts are
coincident with a blob boundary.

--
jaime


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Attachments:
Download 'blob-clouds-test-03d-containers.jpg' (74 KB)

Preview of image 'blob-clouds-test-03d-containers.jpg'
blob-clouds-test-03d-containers.jpg


 

From: Jaime Vives Piqueres
Subject: Re: concentric blobs clouds
Date: 26 Apr 2016 12:58:16
Message: <571f9e28@news.povray.org>
Another one using the exact same clouds but with a sunset lighting.

--
jaime


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Attachments:
Download 'blob-clouds-test-03e.jpg' (49 KB)

Preview of image 'blob-clouds-test-03e.jpg'
blob-clouds-test-03e.jpg


 

From: Norbert Kern
Subject: Re: concentric blobs clouds
Date: 26 Apr 2016 13:20:00
Message: <web.571fa3065193772e670f6e990@news.povray.org>
Jaime Vives Piqueres <jai### [at] ignoranciaorg> wrote:

> > Nice and fluffy as it should be.
>
>    Thanks... perhaps too fluffy, tough.
>
> > The method of averaging object patterns will be of further use - at least I hope
> > so...
>
>   Well, it's nothing fancy, just the average pattern. The real trick is
> that the averaged blobs are concentric (with diminishing radius and the
> same threshold):
>
>
>    interior{
>      media{
>        method 3 intervals 1 samples Cloud_Samples
>        scattering{2,.01}
>        absorption .005
>        density{
>          average
>          density_map{
>            [1
>              object{
>                cloud_a
>                color rgb 0
>                color rgb .25
>              }
>              warp{turbulence .5}
>              scale 2 warp{turbulence .67} scale 1/2
>              scale 4 warp{turbulence 1} scale 1/4
>            ]
>            [1
>              object{
>                cloud_b
>                color rgb 0
>                color rgb .5
>              }
>              warp{turbulence .5}
>              scale 2 warp{turbulence .67} scale 1/2
>            ]
>            [1
>              object{
>                cloud_c
>                color rgb 0
>                color rgb .75
>              }
>              warp{turbulence .5}
>            ]
>            [1
>              object{
>                cloud_d
>                color rgb 0
>                color rgb 1
>              }
>              warp{turbulence .5}
>            ]
>          }
>        }
>      }
>    }
>
> --
> jaime


Thank you for the code snippet.
Concentric is clear, otherwise it would be similar to proximity patterns.
But, who knows...

Norbert


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From: clipka
Subject: Re: concentric blobs clouds
Date: 26 Apr 2016 15:27:14
Message: <571fc112@news.povray.org>
Am 26.04.2016 um 18:58 schrieb Jaime Vives Piqueres:
> Another one using the exact same clouds but with a sunset lighting.

You folks are amazing!


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