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30 Jul 2024 04:20:45 EDT (-0400)
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From: Bill Pragnell
Subject: Re: Ringworld
Date: 14 Oct 2013 03:40:01
Message: <web.525b9ec8f2e6f38c5b7d07940@news.povray.org>
Thomas de Groot <tho### [at] degrootorg> wrote:
> For this see e.g.:
> http://news.povray.org/povray.binaries.images/thread/%3C4c249911@news.povray.org%3E/
>
> Thomas

Another, earlier, detailed discussion here:

http://news.povray.org/povray.binaries.images/thread/%3C43635ed8%241%40news.povray.org%3E/


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From: Thomas de Groot
Subject: Re: Ringworld - a few solutions
Date: 14 Oct 2013 03:57:14
Message: <525ba3da@news.povray.org>
First problem solved.

1) comment out the atmosphere.

2) In your cloud texture, replace the finish either by:

   finish {ambient1 diffuse 1}	// no radiosity

or:

   finish {emission 1 diffuse 1}	// radiosity

3) In your cloud texture, replace the scale by:

   scale ring_width/2000

Now the clouds become visible above the camera. The scale is important 
for this view. The Ringworld is so incredibly huge that what looks right 
from space is only a grey expanse seen from ground level. Cloud patterns 
like on Earth would look tiny on the Ringworld.

4) The problem is your atmosphere which generates the artefact in the 
foreground of the image. This seems probably to be an epsilon effect but 
I am not so sure about that as without atmosphere the scene renders 
properly. I would like the opinion of experts on this.

In any case replace the scattering by:

   scattering {4, <0.1, 0.3, 1.0> * 1000000/ring_radius}

This will make the atmosphere visible.

See the attached image for the state of the art.


Thomas


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Attachments:
Download 'ringworld_new_scaled.png' (79 KB)

Preview of image 'ringworld_new_scaled.png'
ringworld_new_scaled.png


 

From: Thomas de Groot
Subject: Re: Ringworld
Date: 14 Oct 2013 04:01:27
Message: <525ba4d7$1@news.povray.org>
On 14-10-2013 9:35, Bill Pragnell wrote:
>
> Another, earlier, detailed discussion here:
>
>
http://news.povray.org/povray.binaries.images/thread/%3C43635ed8%241%40news.povray.org%3E/
>
>

Ah! Thanks Bill! That is the one I wanted also to find and just forgot :-)

It confirms clearly the epsilon precision problem here.

Thomas


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From: posfan12
Subject: Re: Ringworld
Date: 14 Oct 2013 04:41:29
Message: <525bae39@news.povray.org>
I'm going to focus on long range pics now instead of shots from the surface.

I got rid of the atmosphere and replaced it with a simple faded pigment. 
I also switched the texture for the water surface with a highly 
reflective one.

I'm not real happy with the render since you can't see much color. About 
all you can see are the clouds.


Mike


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Attachments:
Download 'ringworld_new_flattened_01.png' (32 KB)

Preview of image 'ringworld_new_flattened_01.png'
ringworld_new_flattened_01.png


 

From: posfan12
Subject: Re: Ringworld
Date: 14 Oct 2013 04:53:00
Message: <525bb0ec$1@news.povray.org>
Here's a render with the faded "atmosphere" pigment removed and the 
water returned to its original non-reflective texture.

It looks too cartoon-ey and fake.

-- 
http://isometricland.net


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Download 'ringworld_new_flattened_03.png' (26 KB)

Preview of image 'ringworld_new_flattened_03.png'
ringworld_new_flattened_03.png


 

From: Thomas de Groot
Subject: Re: Ringworld
Date: 14 Oct 2013 06:51:05
Message: <525bcc99$1@news.povray.org>
On 14-10-2013 10:52, posfan12 wrote:
> Here's a render with the faded "atmosphere" pigment removed and the
> water returned to its original non-reflective texture.
>
> It looks too cartoon-ey and fake.
>

The first one may be more realistic, this one looks more believable 
taking artistic licence into account. This is more or less how Larry 
Niven describes the first views of the Ringworld.

However, I think that the oceans are not only concentrated in the middle 
of the ring. And there are some very large ones too.

Thomas


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From: posfan12
Subject: Re: Ringworld
Date: 14 Oct 2013 12:26:21
Message: <525c1b2d@news.povray.org>
I've tweaked the landscape a bit and added two belts of clouds. I'm not 
sure the two belts make sense on the ringworld. On Earth there is one 
cloud belt around the equator, and several jet streams I think.

-- 
http://isometricland.net


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Attachments:
Download 'ringworld_new_smaller_05.png' (553 KB)

Preview of image 'ringworld_new_smaller_05.png'
ringworld_new_smaller_05.png


 

From: posfan12
Subject: Re: Ringworld
Date: 14 Oct 2013 12:28:49
Message: <525c1bc1$1@news.povray.org>
On 10/14/2013 6:50 AM, Thomas de Groot wrote:
> The first one may be more realistic, this one looks more believable
> taking artistic licence into account. This is more or less how Larry
> Niven describes the first views of the Ringworld.
>
> However, I think that the oceans are not only concentrated in the middle
> of the ring. And there are some very large ones too.
>
> Thomas

I wasn't satisfied with my other attempts at generating the landscape. 
There are supposed to be mountains along each edge of the ring, correct?

Also, I liked the idea of having a navigable water corridor circling the 
entire structure.


-- 
http://isometricland.net


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From: posfan12
Subject: Re: Ringworld - a few solutions
Date: 14 Oct 2013 19:40:33
Message: <525c80f1@news.povray.org>
On 10/14/2013 3:56 AM, Thomas de Groot wrote:
> First problem solved.
>
> 1) comment out the atmosphere.
>
> 2) In your cloud texture, replace the finish either by:
>
>    finish {ambient1 diffuse 1}    // no radiosity
>
> or:
>
>    finish {emission 1 diffuse 1}    // radiosity
>
> 3) In your cloud texture, replace the scale by:
>
>    scale ring_width/2000
>
> Now the clouds become visible above the camera. The scale is important
> for this view. The Ringworld is so incredibly huge that what looks right
> from space is only a grey expanse seen from ground level. Cloud patterns
> like on Earth would look tiny on the Ringworld.
>
> 4) The problem is your atmosphere which generates the artefact in the
> foreground of the image. This seems probably to be an epsilon effect but
> I am not so sure about that as without atmosphere the scene renders
> properly. I would like the opinion of experts on this.
>
> In any case replace the scattering by:
>
>    scattering {4, <0.1, 0.3, 1.0> * 1000000/ring_radius}
>
> This will make the atmosphere visible.
>
> See the attached image for the state of the art.
>
>
> Thomas

Thanks so much! I will try out these settings next time I do a close-up 
shot.


Mike
-- 
http://isometricland.net


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From: posfan12
Subject: Re: Ringworld
Date: 15 Oct 2013 00:42:26
Message: <525cc7b2@news.povray.org>
Here's my latest render. Not realistic, but it looks OK. You can now see 
a little hint of blue in the ring. Not much green however.


-- 
http://isometricland.net


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Attachments:
Download 'ringworld_new_smaller_07.png' (108 KB)

Preview of image 'ringworld_new_smaller_07.png'
ringworld_new_smaller_07.png


 

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