I decided to try my own hand at creating a ringworld. Here are the results. I'm
not too happy with the sun. I'm using LighsysIV but the sun doesn't look yellow
enough to me. But then maybe in space that's what the sun looks like. I dunno.

I also need to make the water reflective.

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Attachments:
Download 'ringworld_new_01.png' (112 KB)

Preview of image 'ringworld_new_01.png'

On 11-10-2013 12:34, posfan12 wrote:
> I decided to try my own hand at creating a ringworld. Here are the results. I'm
> not too happy with the sun. I'm using LighsysIV but the sun doesn't look yellow
> enough to me. But then maybe in space that's what the sun looks like. I dunno.
>
> I also need to make the water reflective.
>

Looking good imo. Land/sea distribution is much better than the 
randomness in my macro. What K do you use for the sun colour? Around 
6200 or lower fairly yellow, but indeed may not look as such in space, 
or from the surface. The glare makes it white I suppose.

One question though: are the overall proportions of the system right? 
 From the image I suspect that the Ringworld is much too wide compared 
to its diameter. See attached table.

Thomas

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Attachments:
Download 'ringworld parameters.xls.dat' (29 KB)

Thomas de Groot <tho### [at] degrootorg> wrote:
> Looking good imo. Land/sea distribution is much better than the
> randomness in my macro. What K do you use for the sun colour? Around
> 6200 or lower fairly yellow, but indeed may not look as such in space,
> or from the surface. The glare makes it white I suppose.
>
> One question though: are the overall proportions of the system right?
>  From the image I suspect that the Ringworld is much too wide compared
> to its diameter. See attached table.
>
> Thomas

Thanks!

I'm using 6500 for the K.

The scales are way off. For instance the radius of the sun is 1, and the ring is
10, etc. I will fix those later.

Mike

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Thomas de Groot <tho### [at] degrootorg> wrote:
> Looking good imo. Land/sea distribution is much better than the
> randomness in my macro. What K do you use for the sun colour? Around
> 6200 or lower fairly yellow, but indeed may not look as such in space,
> or from the surface. The glare makes it white I suppose.
>
> One question though: are the overall proportions of the system right?
>  From the image I suspect that the Ringworld is much too wide compared
> to its diameter. See attached table.
>
> Thomas

OK, I am trying to apply the dimensions in your Excel file. Problem is, if I
zoom out far enough for the ring to be in view, I can no longer see the sun! The
sun doesn't show up at all.

Is this intentional?


Mike

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"posfan12" <nomail@nomail> wrote:
> OK, I am trying to apply the dimensions in your Excel file. Problem is, if I
> zoom out far enough for the ring to be in view, I can no longer see the sun! The
> sun doesn't show up at all.
>
> Is this intentional?
>
>
> Mike


Never mind. It's an issue with media. See my post in povray.text.scene-files.


Mike

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"posfan12" <nomail@nomail> wrote:
> "posfan12" <nomail@nomail> wrote:
> > OK, I am trying to apply the dimensions in your Excel file. Problem is, if I
> > zoom out far enough for the ring to be in view, I can no longer see the sun! The
> > sun doesn't show up at all.
> >
> > Is this intentional?
> >
> >
> > Mike
>
>
> Never mind. It's an issue with media. See my post in povray.text.scene-files.
>
>
> Mike

No, it's still to small! Even after I remove the media.

:(


Mike

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> "posfan12" <nomail@nomail> wrote:
>> "posfan12" <nomail@nomail> wrote:
>>> OK, I am trying to apply the dimensions in your Excel file. Problem is, if I
>>> zoom out far enough for the ring to be in view, I can no longer see the sun! The
>>> sun doesn't show up at all.
>>>
>>> Is this intentional?
>>>
>>>
>>> Mike
>>
>>
>> Never mind. It's an issue with media. See my post in povray.text.scene-files.
>>
>>
>> Mike
>
> No, it's still to small! Even after I remove the media.
>
> :(
>
>
> Mike
>

If the ring have about the same radius as Earth's orbit, it make it's 
radius about 160 000 000 Km. That's realy huge.

to be even larger than that to maintain a correct temperature.


Compare it to the actual size of the sun. The sun may very well be 
smaller than a single pixel unless you render an image large enough.
Also, the ring itself would be extremely narrow, probably about a single 
pixel whide, at most. If the ring does have a visible width, it would 
mean that it's something like more than 1 000 000 Km whide...

You need to use artistic liberty by not using realistic proportions if 
you want the ring and the sun to be both visible.



Alain

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Alain <kua### [at] videotronca> wrote:
> If the ring have about the same radius as Earth's orbit, it make it's
> radius about 160 000 000 Km. That's realy huge.

> to be even larger than that to maintain a correct temperature.
>
>
> Compare it to the actual size of the sun. The sun may very well be
> smaller than a single pixel unless you render an image large enough.
> Also, the ring itself would be extremely narrow, probably about a single
> pixel whide, at most. If the ring does have a visible width, it would
> mean that it's something like more than 1 000 000 Km whide...
>
> You need to use artistic liberty by not using realistic proportions if
> you want the ring and the sun to be both visible.
>
>
>
> Alain

OK, thanks for the advice. I will fudge the dimensions a bit.


Mike

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"posfan12" <nomail@nomail> wrote:
> I decided to try my own hand at creating a ringworld. Here are the results. I'm
> not too happy with the sun. I'm using LighsysIV but the sun doesn't look yellow
> enough to me. But then maybe in space that's what the sun looks like. I dunno.

The Sun's surface temperature is about 5800K.  I read some time ago that it is
slightly bluer than a black body of the same temperature, but I cannot now find
information about that.

The Sun does look whiter in space than from Earth, because from Earth, the
atmosphere scatters out some of the shorter wavelengths.  That's why the sky is
blue.  If you combine the blue of the sky with the yellowish-white of the Sun,
you'll get roughly the actual color of the Sun (although not exactly, because
the atmosphere does absorb some color).

Note that even from Earth, the Sun is not as yellow as most people think it is.
A sheet of white paper in direct sunlight indoors (where the blue from the sky
is mostly blocked) still looks white, doesn't it?  That the Sun is thought to be
yellower than it really is seems to be some psychological effect that to my
knowledge there's no definitive explanation.

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"posfan12" <nomail@nomail> wrote:
> OK, thanks for the advice. I will fudge the dimensions a bit.

Or if you don't want to fudge the dimensions, you can add diffraction artifacts
(spikes and rings), lens flares, or a media glow.

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