"dave vanhorn" <mic### [at] gmailcom> wrote:
> I'd also be interested in how to do a mobius strip.

Posted in binary scene-files.

-tgq

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"Trevor G Quayle" <Tin### [at] hotmailcom> wrote:
> "dave vanhorn" <mic### [at] gmailcom> wrote:
> > I'd also be interested in how to do a mobius strip.
>
> Posted in binary scene-files.
>
> -tgq

Hmm, don't know where my original response went...
Anyways, I posted a series of macros I did about 4 years ago.  There is a
mesh2 mobius strip with uv_mapping support and a macro for a mobius built
of a user-defined object.  Hope this is of some use for you.

-tgq

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dave vanhorn wrote:
> Has anyone done one of these, either by CSG or isosurface?  I've been 
> playing with stretched rings, but they just don't look right.
> 

The simplest CSG would probably be for example, a union of spheres
along the shape. The shape of infty symbol
is the lemniscate - see e.g.
http://mathworld.wolfram.com/Lemniscate.html
there you can find the parametric equations for it.

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bart wrote:
> dave vanhorn wrote:
>> Has anyone done one of these, either by CSG or isosurface?  I've been 
>> playing with stretched rings, but they just don't look right.
>>
> 
> The simplest CSG would probably be for example, a union of spheres
> along the shape. The shape of infty symbol
> is the lemniscate - see e.g.
> http://mathworld.wolfram.com/Lemniscate.html
> there you can find the parametric equations for it.

...or you can even try to slice a toric section of a torus...

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I don't see it on the server yet, my email is mic### [at] gmailcom if you 
don't mind sending it direct.


"Trevor G Quayle" <Tin### [at] hotmailcom> wrote in message 
news:web.457d68d6acb37f29c150d4c10@news.povray.org...
> "Trevor G Quayle" <Tin### [at] hotmailcom> wrote:
>> "dave vanhorn" <mic### [at] gmailcom> wrote:
>> > I'd also be interested in how to do a mobius strip.
>>
>> Posted in binary scene-files.
>>
>> -tgq
>
> Hmm, don't know where my original response went...
> Anyways, I posted a series of macros I did about 4 years ago.  There is a
> mesh2 mobius strip with uv_mapping support and a macro for a mobius built
> of a user-defined object.  Hope this is of some use for you.
>
> -tgq
>
>
>

Post a reply to this message

bart wrote:
> bart wrote:
>> dave vanhorn wrote:
>>> Has anyone done one of these, either by CSG or isosurface?  I've been 
>>> playing with stretched rings, but they just don't look right.
>>>
>>
>> The simplest CSG would probably be for example, a union of spheres
>> along the shape. The shape of infty symbol
>> is the lemniscate - see e.g.
>> http://mathworld.wolfram.com/Lemniscate.html
>> there you can find the parametric equations for it.
> 
> ...or you can even try to slice a toric section of a torus...
// e.g. like this:
//===========8<=============
camera {location  -z}

#local R1=0.6;
#local R2=0.55;
#local r1=0.3;
#local r2=0.22;

#local p=r1*1.05;
#local dp=0.001;

#local infty=difference{
   torus{R1,r1}
   torus{R2,r2}
   plane{z,p}
   plane{-z,-p-dp}
}

#object{infty
   pigment{rgb y}
}
//===========8<=============

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Scaling the vertical component down to +/- 1, and making it a little thinner 
got me to where I need to be.. Thanks!  :)


"Nicolas George" <nicolas$george@salle-s.org> wrote in message 
news:457d33ff$1@news.povray.org...
> "dave vanhorn"  wrote in message <457cb234@news.povray.org>:
>> Has anyone done one of these, either by CSG or isosurface?
>
> An infinity symbol is not a 3D object, so the question is: how do intend 
> to
> make it 3D? Do you want it infinitely thin? Flat but thick? Round?
>
> You can do something easy with a sphere sweep:
>
>  sphere_sweep {
>    b_spline
>    9,
>    <-2, -2, 0>, 0.2,
>    < 0,  0, 0>, 0.2,
>    < 2,  2, 0>, 0.2,
>    < 2, -2, 0>, 0.2,
>    < 0,  0, 0>, 0.2,
>    <-2,  2, 0>, 0.2,
>    <-2, -2, 0>, 0.2,
>    < 0,  0, 0>, 0.2,
>    < 2,  2, 0>, 0.2
>  }

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Why couldn't we have had povray in geometry class... :)

>> ...or you can even try to slice a toric section of a torus...
> // e.g. like this:
> //===========8<=============
> camera {location  -z}
>
> #local R1=0.6;
> #local R2=0.55;
> #local r1=0.3;
> #local r2=0.22;
>
> #local p=r1*1.05;
> #local dp=0.001;
>
> #local infty=difference{
>   torus{R1,r1}
>   torus{R2,r2}
>   plane{z,p}
>   plane{-z,-p-dp}
> }
>
> #object{infty
>   pigment{rgb y}
> }
> //===========8<=============

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"dave vanhorn" <mic### [at] gmailcom> wrote:
> I don't see it on the server yet, my email is mic### [at] gmailcom if you
> don't mind sending it direct.
>
>
> "Trevor G Quayle" <Tin### [at] hotmailcom> wrote in message
> news:web.457d68d6acb37f29c150d4c10@news.povray.org...
> > "Trevor G Quayle" <Tin### [at] hotmailcom> wrote:
> >> "dave vanhorn" <mic### [at] gmailcom> wrote:
> >> > I'd also be interested in how to do a mobius strip.
> >>
> >> Posted in binary scene-files.
> >>
> >> -tgq
> >
> > Hmm, don't know where my original response went...
> > Anyways, I posted a series of macros I did about 4 years ago.  There is a
> > mesh2 mobius strip with uv_mapping support and a macro for a mobius built
> > of a user-defined object.  Hope this is of some use for you.
> >
> > -tgq
> >
> >
> >

It should be in p.b.scene-files (entitled mobius macro):
http://news.povray.org/povray.binaries.scene-files/message/%3Cweb.457d66a665d69017c150d4c10%40news.povray.org%3E/#%3Cwe
b.457d66a665d69017c150d4c10%40news.povray.org%3E

Let me know if you still don't see it.

-tgq

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dave vanhorn nous apporta ses lumieres en ce 2006-12-11 14:20:
> I don't see it on the server yet, my email is m i c r o b r i x@g m a i l.c o m if
you 
> don't mind sending it direct.



You should always obfuscate your e-mail address. Adding spacesm, or dots, or 
dashes, or ??? is a possibility, as well as adding anything that is easily 
notisable by somebody but not by a harvest bot.
This NG is prety clean, but you never know. Beter be to prudent than sory with 
an inbox overflowing with spam.

-- 
Alain
-------------------------------------------------
At the feast of ego everyone leaves hungry.
	Bentley's House of Coffee and Tea, Tucson, AZ

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