POV-Ray : Newsgroups : povray.general : Neon Signs Server Time
5 Aug 2024 18:17:15 EDT (-0400)
  Neon Signs (Message 1 to 8 of 8)  
From: Rohan Bernett
Subject: Neon Signs
Date: 28 Jul 2002 22:44:01
Message: <web.3d44abd7e694ad8fd02c7b870@news.povray.org>
Does anybody know of a good way to make a neon sign, especially one that
emits light?

Rohan _e_ii


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From: Rafal 'Raf256' Maj
Subject: Re: Neon Signs
Date: 28 Jul 2002 23:07:45
Message: <Xns925A3395AD3B6raf256com@204.213.191.226>
"Rohan Bernett" <rox### [at] yahoocom> wrote in 
news:web.3d44abd7e694ad8fd02c7b870@news.povray.org

> Does anybody know of a good way to make a neon sign, especially one that
> emits light?

I suggest - glass, maybe media inside glass, and :
a) area_light x*10,y,10,1 to make line area lights
b) maybe use emitting media with radiosity to make madia realy emit light ?
c) use many light_sources placed inside each neone part i.e. in loop

-- 
#macro g(U,V)(.4*abs(sin(9*sqrt(pow(x-U,2)+pow(y-V,2))))*pow(1-min(1,(sqrt(
pow(x-U,2)+pow(y-V,2))*.3)),2)+.9)#end#macro p(c)#if(c>1)#local l=mod(c,100
);g(2*div(l,10)-8,2*mod(l,10)-8)*p(div(c,100))#else 1#end#end light_source{
y 2}sphere{z*20 9pigment{function{p(26252423)*p(36455644)*p(66656463)}}}//M


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From: Peter Popov
Subject: Re: Neon Signs
Date: 29 Jul 2002 03:59:57
Message: <ldt9kucftabnsnkp0b42rakvg6ihq508ro@4ax.com>
On 28 Jul 2002 23:07:45 -0400, "Rafal 'Raf256' Maj" <raf### [at] raf256com>
wrote:

>I suggest - glass, maybe media inside glass, and :
>a) area_light x*10,y,10,1 to make line area lights

c) is better, as area lights only behave as expected when it comes to
shadows.

>b) maybe use emitting media with radiosity to make madia realy emit light ?

This could prove to be slow...

>c) use many light_sources placed inside each neone part i.e. in loop

Probably the best solution, yes. Especially when you add emitting
media to fake the glow.


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


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From: Christopher James Huff
Subject: Re: Neon Signs
Date: 29 Jul 2002 10:26:38
Message: <chrishuff-6C7341.09193529072002@netplex.aussie.org>
In article <ldt9kucftabnsnkp0b42rakvg6ihq508ro@4ax.com>,
 Peter Popov <pet### [at] vipbg> wrote:

> >b) maybe use emitting media with radiosity to make madia realy emit light ?
> 
> This could prove to be slow...

A texture with a high ambient and maybe some transparency would be 
faster.

-- 
Christopher James Huff <chr### [at] maccom>
POV-Ray TAG e-mail: chr### [at] tagpovrayorg
TAG web site: http://tag.povray.org/


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From: Ron Parker
Subject: Re: Neon Signs
Date: 29 Jul 2002 15:42:14
Message: <slrnakb6kp.dc5.ron.parker@fwi.com>
On Sun, 28 Jul 2002 22:43:35 EDT, Rohan Bernett wrote:
> Does anybody know of a good way to make a neon sign, especially one that
> emits light?

I can't help with the "emits light" part but try my signature for the rest.

-- 
#macro R(L P)sphere{L F}cylinder{L P F}#end#macro P(V)merge{R(z+a z)R(-z a-z)R(a
-z-z-z a+z)torus{1F clipped_by{plane{a 0}}}translate V}#end#macro Z(a F T)merge{
P(z+a)P(z-a)R(-z-z-x a)pigment{rgbt 1}hollow interior{media{emission T}}finish{
reflection.1}}#end Z(-x-x.2y)Z(-x-x.4x)camera{location z*-10rotate x*90}


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From: Ed Jackson
Subject: Re: Neon Signs
Date: 31 Jul 2002 10:17:53
Message: <pan.2002.07.31.14.17.51.992920.17877@iastate.edu>
On Mon, 29 Jul 2002 09:19:35 -0500, Christopher James Huff wrote:

> In article <ldt9kucftabnsnkp0b42rakvg6ihq508ro@4ax.com>,
>  Peter Popov <pet### [at] vipbg> wrote:
> 
>> >b) maybe use emitting media with radiosity to make madia realy emit
>> >light ?
>> 
>> This could prove to be slow...
> 
> A texture with a high ambient and maybe some transparency would be
> faster. 

I tried to do this recently, and didn't have very good luck.  The neon
tube itself looks okay (not great) with a high ambient, but it doesn't do
as much as you'd expect for illumination.  Maybe my radiosity settings
weren't too good, but even with a count of 500 and an ambient as high as
10000, it was far from convincing.

Similar results with emitting media in a clear object.

I also never came up with a good way to control the density of the media
so that it would be highest along the central axis of the tube and fall
off toward the outside like a real neon tube.  (The tube was a complex
curve made with a sphere sweep).

	-Ed


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From: Peter Popov
Subject: Re: Neon Signs
Date: 31 Jul 2002 19:21:41
Message: <5srgkuc3ksflncmsvsip472aifpub2di05@4ax.com>
On Wed, 31 Jul 2002 09:17:52 -0500, Ed Jackson <eja### [at] iastateedu>
wrote:

>I tried to do this recently, and didn't have very good luck.  The neon
>tube itself looks okay (not great) with a high ambient, but it doesn't do
>as much as you'd expect for illumination.  Maybe my radiosity settings
>weren't too good, but even with a count of 500 and an ambient as high as
>10000, it was far from convincing.

Did you adjust max_sample accordingly?


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


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From: Ed Jackson
Subject: Re: Neon Signs
Date: 1 Aug 2002 17:49:24
Message: <pan.2002.08.01.21.49.24.78858.18949@iastate.edu>
On Wed, 31 Jul 2002 18:21:37 -0500, Peter Popov wrote:


>>I tried to do this recently, and didn't have very good luck.  The neon
>>tube itself looks okay (not great) with a high ambient, but it doesn't
>>do as much as you'd expect for illumination.  Maybe my radiosity
>>settings weren't too good, but even with a count of 500 and an ambient
>>as high as 10000, it was far from convincing.
> 
> Did you adjust max_sample accordingly?
> 

Actually, I gave up and moved on to other things.  I might go back to it
eventually.  However, I just had it up against a wall, and it didn't even
illuminate the wall convincingly.  *shrug*  I guess I just need to play
with it some more.

	-Ed


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