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From: Simon Lemieux
Subject: Infinite primitives?
Date: 12 Nov 2000 01:59:25
Message: <3A0E4DFE.F0C6A88B@yahoo.com>
Hi,
	I was wondering if it was possible to simply have an infinite cylinder? 
Without any tricks... this should normally be trivial for the renderer... but
was this coded?

Thanks,
	Simon
-- 
+-------------------------+----------------------------------+
| Simon Lemieux           | Website : http://www.666Mhz.net  |
| Email : Sin### [at] 666Mhznet | POV-Ray, OpenGL, C++ and more... |
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From: Margus Ramst
Subject: Re: Infinite primitives?
Date: 12 Nov 2000 10:05:25
Message: <3A0EB1DE.C830462B@peak.edu.ee>
Simon Lemieux wrote:
> 
> Hi,
>         I was wondering if it was possible to simply have an infinite cylinder?
> Without any tricks... this should normally be trivial for the renderer... but
> was this coded?
> 

What do you need it for? Scaling the cylinder up along its axis can make it seem
infinite for any purpose I can think of.
You can make an isosurface with an infinite cylindrical function, but this too
will have to be contained by an infinite object.

-- 
Margus Ramst

Personal e-mail: mar### [at] peakeduee
TAG (Team Assistance Group) e-mail: mar### [at] tagpovrayorg


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From: Chris Huff
Subject: Re: Infinite primitives?
Date: 12 Nov 2000 10:19:35
Message: <chrishuff-76AD89.10194412112000@news.povray.org>
In article <3A0EB1DE.C830462B@peak.edu.ee>, Margus Ramst 
<mar### [at] peakeduee> wrote:

> What do you need it for? Scaling the cylinder up along its axis can 
> make it seem infinite for any purpose I can think of.
> You can make an isosurface with an infinite cylindrical function, but 
> this too will have to be contained by an infinite object.

As I recall, the list of possible contained_by objects is very 
short...box and sphere last I heard.

However, a quadric should do the job, if an infinite cylinder really is 
necessary. Maybe a "infinite" keyword could be added to cones and 
cylinders...all it would have to do is remove bounding and not clip the 
ends and render disks there.

-- 
Christopher James Huff
Personal: chr### [at] maccom, http://homepage.mac.com/chrishuff/
TAG: chr### [at] tagpovrayorg, http://tag.povray.org/

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From: Simon Lemieux
Subject: Re: Infinite primitives?
Date: 12 Nov 2000 12:03:04
Message: <3A0EDB77.6BCAE4BC@yahoo.com>
> However, a quadric should do the job, if an infinite cylinder really is
> necessary. Maybe a "infinite" keyword could be added to cones and
> cylinders...all it would have to do is remove bounding and not clip the
> ends and render disks there.

Thanks, the quadrics work pretty fine!

-- 
+-------------------------+----------------------------------+
| Simon Lemieux           | Website : http://www.666Mhz.net  |
| Email : Sin### [at] 666Mhznet | POV-Ray, OpenGL, C++ and more... |
+-------------------------+----------------------------------+


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From: Margus Ramst
Subject: Re: Infinite primitives?
Date: 12 Nov 2000 15:30:45
Message: <3A0EFE20.83A2EFE2@peak.edu.ee>
Chris Huff wrote:
> 
> In article <3A0EB1DE.C830462B@peak.edu.ee>, Margus Ramst
> <mar### [at] peakeduee> wrote:
> 
> > this too will have to be contained by an infinite object.
> 
> As I recall, the list of possible contained_by objects is very
> short...box and sphere last I heard.
> 

*ack* I meant to say "finite object"

-- 
Margus Ramst

Personal e-mail: mar### [at] peakeduee
TAG (Team Assistance Group) e-mail: mar### [at] tagpovrayorg


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From: John VanSickle
Subject: Re: Infinite primitives?
Date: 12 Nov 2000 21:17:03
Message: <3A0F50A5.1C648BDF@erols.com>
Simon Lemieux wrote:
> 
> I was wondering if it was possible to simply have an infinite
> cylinder?
> Without any tricks... this should normally be trivial for the
> renderer... but was this coded?

I think this ought to work.  It uses the Reorient() macro from my
Thoroughly Useful Macros file:

#macro InfiniteCylinder(PointA,PointB,Radius)
quadric { <1,0,1>,<0,0,0>,<0,0,0>,-Radius*Radius
  Reorient(y,vnormalize(PointB-PointA))
  translate PointA
}
#end

Hope this helps,
John
-- 
ICQ: 46085459


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From: Peter Popov
Subject: Re: Infinite primitives?
Date: 13 Nov 2000 03:34:13
Message: <3n2u0t0i36buqceccj661fi3tpg2fdo9ad@4ax.com>
On Sun, 12 Nov 2000 02:59:58 -0500, Simon Lemieux
<lem### [at] yahoocom> wrote:

>Hi,
>	I was wondering if it was possible to simply have an infinite cylinder? 
>Without any tricks... this should normally be trivial for the renderer... but
>was this coded?

A quadric (anyone remember these?) should do it. Look at shapes.inc
and shapesq.inc in the standard POV-Ray package.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] usanet
TAG      e-mail : pet### [at] tagpovrayorg


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From: Warp
Subject: Re: Infinite primitives?
Date: 13 Nov 2000 09:27:03
Message: <3a0ffa37@news.povray.org>
Peter Popov <pet### [at] usanet> wrote:
: A quadric (anyone remember these?) should do it.

  Isosurfaces killed quartics and other poly objects... RIP.

  ... Or perhaps not. You can create infinite surfaces with polys but not
with isosurfaces. Polys also are more accurate (but usually slower).

  Btw, see http://iki.fi/warp/polytutorial/

-- 
main(i,_){for(_?--i,main(i+2,"FhhQHFIJD|FQTITFN]zRFHhhTBFHhhTBFysdB"[i]
):_;i&&_>1;printf("%s",_-70?_&1?"[]":" ":(_=0,"\n")),_/=2);} /*- Warp -*/


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From: Peter Popov
Subject: Re: Infinite primitives?
Date: 15 Nov 2000 03:53:57
Message: <a5j41tgi5rsed4s8tckd61gdn4a68otpcb@4ax.com>
On 13 Nov 2000 09:27:03 -0500, Warp <war### [at] tagpovrayorg> wrote:

>Peter Popov <pet### [at] usanet> wrote:
>: A quadric (anyone remember these?) should do it.
>
>  Isosurfaces killed quartics and other poly objects... RIP.
>
>  ... Or perhaps not. You can create infinite surfaces with polys but not
>with isosurfaces. Polys also are more accurate (but usually slower).

That's exactly what I had in mind. With all the iso frenzy, people
seem to have forgotten about the good ole infinite primitives. They
still have their uses.


Peter Popov ICQ : 15002700
Personal e-mail : pet### [at] usanet
TAG      e-mail : pet### [at] tagpovrayorg


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From: Margus Ramst
Subject: Re: Infinite primitives?
Date: 15 Nov 2000 20:43:46
Message: <3A133C08.BDF71683@peak.edu.ee>
Peter Popov wrote:
> 
> That's exactly what I had in mind. With all the iso frenzy, people
> seem to have forgotten about the good ole infinite primitives. They
> still have their uses.
> 

Out of curiosity, what uses?
I.e. how is a "truly infinite" quadric cylinder better than a regular cylinder
scaled so long that POV considers it infinite?

-- 
Margus Ramst

Personal e-mail: mar### [at] peakeduee
TAG (Team Assistance Group) e-mail: mar### [at] tagpovrayorg


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