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.

Post a reply to this message

I'd also be interested in how to do a mobius strip.

Post a reply to this message

"dave vanhorn" <mic### [at] gmailcom> wrote in message 
news:457cb234@news.povray.org...
> 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.
>

Not as a CSG or an isosurface, but have you considered using the text 
object.
Depending upon what you want it for, an 8 on it's side may serve your 
purposes.

camera {location <0,0,-1>}
light_source { <1, 2, -20> color rgb 1}

text {
  ttf "times.ttf","8",0.2, 0
  pigment {color rgb 1}
  scale <0.5,1,1>
  rotate z*90
  translate 0.3*x
}

Regards,
Chris B.

Post a reply to this message

"Chris B" <c_b### [at] btconnectcomnospam> wrote:
> "dave vanhorn" <mic### [at] gmailcom> wrote in message
> news:457cb234@news.povray.org...
> > 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.
> >
>
> Not as a CSG or an isosurface, but have you considered using the text
> object.
> Depending upon what you want it for, an 8 on it's side may serve your
> purposes.
>
> camera {location <0,0,-1>}
> light_source { <1, 2, -20> color rgb 1}
>
> text {
>   ttf "times.ttf","8",0.2, 0
>   pigment {color rgb 1}
>   scale <0.5,1,1>
>   rotate z*90
>   translate 0.3*x
> }
>
> Regards,
> Chris B.

I found the infinity symbol in the following Windows Fonts, code U+221E. If
it is of any help.
ZTZhongsong
NSimSun
New Gulim
MingLiu


Stephen

Post a reply to this message

"Chris B"  wrote in message <457d22d0@news.povray.org>:
>   ttf "times.ttf","8",0.2, 0

Real mathematicians would use CMSY10.

Post a reply to this message

"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
  }

Post a reply to this message

"dave vanhorn"  wrote in message <457cbdfb@news.povray.org>:
> I'd also be interested in how to do a mobius strip. 

That can be done with a parametric object:

  parametric { 
    function { (1 + v * sin(u / 2)) * cos(u) }
    function { v * cos(u / 2) }
    function { (1 + v * sin(u / 2)) * sin(u) }
    <0, -0.2>, <2 * pi, 0.2>
    contained_by { box { <-1.5, -1.5, -1.5>, <1.5, 1.5, 1.5> } }
  } 

This one is infinitely thin. If you want some thickness, you have to design
a path for the v parameter.

BTW, is it not possible to use vectorial arithmetics for parametric objects?

Post a reply to this message

> This one is infinitely thin. If you want some thickness, you have to 
> design
> a path for the v parameter.

Thanks, I'll check that out.
All my pov experience previous has been with CSG, this is new to me.

> BTW, is it not possible to use vectorial arithmetics for parametric 
> objects?

No idea.

Post a reply to this message

> Not as a CSG or an isosurface, but have you considered using the text
> object.
> Depending upon what you want it for, an 8 on it's side may serve your 
> purposes.


Thanks,  I did think of this last night, but the text ends up as a very 
harsh object, I haven't found any way to round the corners, or otherwise 
soften the appearance.
Something like a sphere sweep would be ideal.

Post a reply to this message

I'll give that a try too, thanks.

That's pov for ya, there's usually at least three ways you didn't think of, 
to do something.  :)

Post a reply to this message

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

Posted in binary scene-files.

-tgq

Post a reply to this message

"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

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.

Post a reply to this message

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...

Post a reply to this message

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<=============

Post a reply to this message

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
>  }

Post a reply to this message

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<=============

Post a reply to this message

"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

Post a reply to this message

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

Post a reply to this message

Stephen nous apporta ses lumieres en ce 2006-12-11 05:04:
> "Chris B" <c_b### [at] btconnectcomnospam> wrote:
>> "dave vanhorn" <mic### [at] gmailcom> wrote in message
>> news:457cb234@news.povray.org...
>>> 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.

>> Not as a CSG or an isosurface, but have you considered using the text
>> object.
>> Depending upon what you want it for, an 8 on it's side may serve your
>> purposes.

>> camera {location <0,0,-1>}
>> light_source { <1, 2, -20> color rgb 1}

>> text {
>>   ttf "times.ttf","8",0.2, 0
>>   pigment {color rgb 1}
>>   scale <0.5,1,1>
>>   rotate z*90
>>   translate 0.3*x
>> }

>> Regards,
>> Chris B.

> I found the infinity symbol in the following Windows Fonts, code U+221E. If
> it is of any help.
> ZTZhongsong
> NSimSun
> New Gulim
> MingLiu
It should be present in most unicode fonts sets at the same place.


> Stephen



Also in arialuni.ttf (same code) and in symbols.ttf

-- 
Alain
-------------------------------------------------
War is an instrument entirely inefficient toward redressing wrong; and
multiplies, instead of indemnifying losses.
Thomas Jefferson

Post a reply to this message

It showed up here about an hour ago, thanks.  Still playing with things..
I have this taking so long to run, that I only have looked at the pretraces 
in the last two days..

The heart isosurface has a glitch that I'm trying to take out without making 
it too hideously long to trace.

Post a reply to this message

[off topic, but I did not start it:)]

Alain  wrote in message <457ddb33@news.povray.org>:
> You should always obfuscate your e-mail address.

Or not. The e-mail in my From: is valid, bot strangely, spambots seems to be
unable to see it, because although I use it on Usenet since several years, I
only got 5 spams through it last month, out of a total of almost 25000 spams
on my various addresses. Of course, the part after the dollar is not a valid
address; the administrator of the MX server tells me it produces a lot of
bounces.

Post a reply to this message

Alain <ele### [at] netscapenet> wrote:

>
> Also in arialuni.ttf (same code) and in symbols.ttf
>
> --
> Alain


So it is, I missed it when I was looking. It’s also in Times New Roman as
well ∞

Stephen

Post a reply to this message