"Darren New" <dne### [at] sanrrcom> schreef in bericht 
news:4c1f8f9c$1@news.povray.org...
> Thomas de Groot wrote:
>> I should look this up of course, but I seem to remember indeed that the 
>> Rim Wall was carved into mountain shapes. In the later books, spill 
>> mountains were added too for the necessary feeding of rivers.
>
> Indeed. ALtho one must wonder why.

For a simple, geological reason: All the dirt transported by the rivers and 
eroded from the landscape would soon fill the seas and oceans. So a feedback 
system is installed which transports the deposited sediments from the oceans 
back to the rim and on "spill" mountains, which in turn are eroded by 
rivers, completing the cycle. Thus a balance is achieved and the original 
ring floor is not exposed.

Spill mountains did not appear in the first book but were a later addition 
because Larry Niven realized the problem. In the same way, I think that the 
description of the Rim Walls evolves from the first book till the later 
ones.

Thomas

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"SharkD" <pos### [at] gmailcom> schreef in bericht 
news:4c1fa175@news.povray.org...
> The book mentions how the bottom (or outside edge) of the ring is shaped 
> like a cake mold due to the sculpting of the mountains, but nothing about 
> the side walls.

Sure. As I answered to Darren, the description of the Rim Walls changes from 
book to book. My memory is vague about the exact wording now. I shall look 
that up when I have got some time.

Thomas

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"Darren New" <dne### [at] sanrrcom> schreef in bericht 
news:4c1f9052$1@news.povray.org...
> Fans should be aware there's a whole new series out, covering what Nessus 
> was doing the whole time he wasn't obvious. Basically, Known Space as told 
> from the puppeteer's point of view.  Very, very fun.

Oh? That is new to me. I shall have to dig that up somewhere. Thanks for 
bringing it to our attention :-)

Thomas

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"Bill Pragnell" <bil### [at] hotmailcom> schreef in bericht 
news:web.4c1fc8aa325a7df34f28787e0@news.povray.org...
> Wikipedia says "Fleet of Worlds", "Juggler of Worlds" and "Destroyer of 
> Worlds".
> I shall have to hunt these down, they sound interesting.

Excellent! Bee noted.

>
> (I only read "Ringworld's Children" quite recently - it was much better 
> than
> Throne, I thought it had the same sort of feel as Engineers).

Agreed. I shall have to revisit again...

Thomas

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"Bill Pragnell" <bil### [at] hotmailcom> schreef in bericht 
news:web.4c1f8057325a7df36dd25f0b0@news.povray.org...
> Now that really is nice... a bit of light bloom and more opaque clouds 
> would
> make it almost perfect.

Thanks, yes this can certainly be improved more.

>
> One thing has just struck me - I don't think the top of the wall would be
> properly visible, especially at night. Since the top sticks out of the
> atmosphere by some 800-900 miles, it should probably be obscured by the 
> sky in
> the same way as the arch, only showing up where in full sunlight. I don't 
> know
> how to make that look believable :\

Indeed. As I wrote in an earlier answer to you, how the Rim Wall is 
perceived from the ground is still a question to me. For the present image, 
I think I can do it by scaling differentially the semi-tranparant sky dome 
so that the Rim Wall lies outside of it. Hoping that no strange artefacts 
will appear in the process. In a future wip I shall experiment with media to 
simulate a proper atmosphere. That is going to be more tricky.

Thomas

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Thomas de Groot wrote:
> "Darren New" <dne### [at] sanrrcom> schreef in bericht 
> news:4c1f8f9c$1@news.povray.org...
>> Thomas de Groot wrote:
>>> I should look this up of course, but I seem to remember indeed that the 
>>> Rim Wall was carved into mountain shapes. In the later books, spill 
>>> mountains were added too for the necessary feeding of rivers.
>> Indeed. ALtho one must wonder why.
> 
> For a simple, geological reason: All the dirt transported by the rivers and 

I meant that one must wonder why the builders would carve the walls into 
hollow mountain shapes. (I.e., your first sentence, rather than the second.)

> Spill mountains did not appear in the first book but were a later addition 
> because Larry Niven realized the problem. In the same way, I think that the 
> description of the Rim Walls evolves from the first book till the later 
> ones.

Yes. Plus, I don't think they came anywhere near the walls in the first 
book. :-) Well, not from the inside, at least.

-- 
Darren New, San Diego CA, USA (PST)
    Eiffel - The language that lets you specify exactly
    that the code does what you think it does, even if
    it doesn't do what you wanted.

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Thomas de Groot wrote:
> Indeed. As I wrote in an earlier answer to you, how the Rim Wall is 
> perceived from the ground is still a question to me.

In the first book, it was generally very difficult to see the walls at all. 
If you measure out the angle from somewhere near the middle of the floor, 
you come to the conclusion they're really not all that hight. Even a wall 
500 miles high (or whatever it was) when seen from half a million miles away 
isn't very big.

-- 
Darren New, San Diego CA, USA (PST)
    Eiffel - The language that lets you specify exactly
    that the code does what you think it does, even if
    it doesn't do what you wanted.

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Darren New <dne### [at] sanrrcom> wrote:
> I meant that one must wonder why the builders would carve the walls into
> hollow mountain shapes. (I.e., your first sentence, rather than the second.)

Well, they only had a finite amount of material, and it was practically
indestructible. No reason to do it any other way really!

> > Spill mountains did not appear in the first book but were a later addition
> > because Larry Niven realized the problem. In the same way, I think that the
> > description of the Rim Walls evolves from the first book till the later
> > ones.
> Yes. Plus, I don't think they came anywhere near the walls in the first
> book. :-) Well, not from the inside, at least.

Nope. They crashed near the middle, headed for the nearest wall, got a small
proportion of the way there, backtracked and jumped out the meteor crater. They
did inspect the walls in some detail before the crash, but, as you say, only
from the outside.

Hmm, I'm sure the walls were sheer on the other side. Perhaps the implication is
that the spill mountains are solid? Whoknows.

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Bill Pragnell wrote:
> Well, they only had a finite amount of material, and it was practically
> indestructible. No reason to do it any other way really!

Why not leave it flat? It's not like you're planning on fooling anyone who 
lives there. That takes even less material than sculpting it.

-- 
Darren New, San Diego CA, USA (PST)
    Eiffel - The language that lets you specify exactly
    that the code does what you think it does, even if
    it doesn't do what you wanted.

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"Darren New" <dne### [at] sanrrcom> schreef in bericht 
news:4c20caea@news.povray.org...
> I meant that one must wonder why the builders would carve the walls into 
> hollow mountain shapes. (I.e., your first sentence, rather than the 
> second.)

Oops! Sorry, my misunderstanding :-)

> Yes. Plus, I don't think they came anywhere near the walls in the first 
> book. :-) Well, not from the inside, at least.

Indeed. In one of the later books, Louis Wu goes to the RimWall and uses the 
transport system at the top.It is where spill mountains are described. I 
don't remember which book that was... :-(

Thomas

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Darren New <dne### [at] sanrrcom> wrote:
> Bill Pragnell wrote:
> > Well, they only had a finite amount of material, and it was practically
> > indestructible. No reason to do it any other way really!
>
> Why not leave it flat? It's not like you're planning on fooling anyone who
> lives there. That takes even less material than sculpting it.

Pretty boring living on a table top tho :) If they wanted a range of ecosystems
they'd have to reproduce a planet's surface topology, surely? And anyway, where
would they put the water? :D

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"Bill Pragnell" <bil### [at] hotmailcom> schreef in bericht 
news:web.4c20cd6e325a7df36dd25f0b0@news.povray.org...
> Hmm, I'm sure the walls were sheer on the other side. Perhaps the 
> implication is
> that the spill mountains are solid? Whoknows.

Yes, the spill mountains should be solid indeed as they serve as sediment 
reservoirs for the rivers.

I am beginning to get unsure about the "sculpting" of the Rim Wall into 
mountain shapes...

Tanj! It becomes really necessary to re-read the series!  ;-)

Thomas

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Bill Pragnell wrote:
> Pretty boring living on a table top tho :)

Mountains!  We're talking about the walls, aren't we?

Given they had islands the size of planets, I don't think they really needed 
the walls to be textured like mountains in order to have mountain terrain.

-- 
Darren New, San Diego CA, USA (PST)
    Eiffel - The language that lets you specify exactly
    that the code does what you think it does, even if
    it doesn't do what you wanted.

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Darren New <dne### [at] sanrrcom> wrote:
> Bill Pragnell wrote:
> > Pretty boring living on a table top tho :)
>
> Mountains!  We're talking about the walls, aren't we?

Yes, sorry, world of my own. Um, dunno. Thomas' reply, that they are sediment
reservoirs, seems the only likely explanation other than pure aesthetics, which
the builders may or may not have been concerned with. (Not, if memory serves).

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Interesting flyby video:

http://www.youtube.com/watch?v=OXZdaQN3r50

I didn't realize a) that the sun was so large WRT the ring, and b) that 
the inner "shadow" ring was so much nearer the outer ring than the sun.


-- 
http://isometricland.com

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"SharkD" <pos### [at] gmailcom> schreef in bericht 
news:4c214569$1@news.povray.org...
> Interesting flyby video:
>
> http://www.youtube.com/watch?v=OXZdaQN3r50
>
> I didn't realize a) that the sun was so large WRT the ring, and b) that 
> the inner "shadow" ring was so much nearer the outer ring than the sun.
>

Nice animation indeed, but:
The shadow squares are wrong. According to Niven, they are located at the 
equivalent of the orbit of Mercury, if the ring were at Earth's distance.

Have you seen the Rama animation?

Five years ago, I distilled the following parameters for the Ringworld 
system:

 RINGWORLD parameters conversion table


      scale factor
     1,00
      sun diameter mi 1.000.000,00

     km 1.610.000,00
      ring radius mi 95.000.000,00

     km 152.950.000,00
      ring width mi 997.000,00

     km 1.605.170,00
      rim wall height mi 1.000,00

     km 1.610,00
      shadow square radius mi 13.000.000,00

     km 20.930.000,00
      shadow square width mi 1.000.000,00

     km 1.610.000,00
      shadow square length mi 2.500.000,00

     km 4.025.000,00
      spill mountain height (1) mi 30,00

     km 48,30
      spill mountain height (2) mi 40,00

     km 64,40



Thomas

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Am 23.06.2010 09:50, schrieb Thomas de Groot:

>> I didn't realize a) that the sun was so large WRT the ring, and b) that
>> the inner "shadow" ring was so much nearer the outer ring than the sun.
>>
>
> Nice animation indeed, but:
> The shadow squares are wrong. According to Niven, they are located at the
> equivalent of the orbit of Mercury, if the ring were at Earth's distance.

To be precise, the shadow squares aren't "wrong" - it's just "some" ring 
world, not the one from Niven's books.

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SharkD <pos### [at] gmailcom> wrote:
> I didn't realize a) that the sun was so large WRT the ring, and b) that
> the inner "shadow" ring was so much nearer the outer ring than the sun.

OK, so it's not Niven's ringworld, but if it was, the sun should also be a lot
smaller. :D As Thomas detailed, for Niven's ringworld, it's basically our sun,
with the ring as Earth's orbit. The ring's width is the same as the sun's
diameter.

(I don't think you'd want the shadow squares that close to the ring floor anyway
- very abrupt nightfall, total cave-like darkness and utterly empty sky at
night... it might even cause the natives to die off depending on their
psychology. Also less efficient - you need more material to make them, and more
energy to spin them up and stabilise them. Plus, in the event of a failure of
the shadow ring, you'd have far less time to do something about it before the
shadow squares hit the ringworld.)

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"clipka" <ano### [at] anonymousorg> schreef in bericht 
news:4c21c501$1@news.povray.org...
> To be precise, the shadow squares aren't "wrong" - it's just "some" ring 
> world, not the one from Niven's books.

Hold the thiefs!!  They stole Niven's ring! ;-)

Thomas

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On 6/23/2010 5:03 AM, Bill Pragnell wrote:
> OK, so it's not Niven's ringworld,

Oops!


-- 
http://isometricland.com

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