POV-Ray : Newsgroups : moray.win : A light bulb Server Time: 3 Sep 2014 04:36:13 GMT
  A light bulb (Message 1 to 6 of 6)  
From: alanr
Subject: A light bulb
Date: 21 Feb 2011 01:25:01
Message: <web.4d61bd5bf7701b391d72ddf90@news.povray.org>
Apologies if this has been understood by others but an explanation I just read
seemed so simple I'm baffled it does not quite work as expected.

In Moray I created a csg union of a point light with a sphere and created a
whiteish material with a finish ambient set to 1, and sphere set no shadow.  But
it renders black, albeit light appears to emit from this object.

Have to turn the scene ambient up full in order to make the sphere look like its
lit, but this of course a produces general glow to all objects from an unseen
source which I dont really want.

Is setting the scene ambient to 1 the only way to get the sphere to "glow" or
have I missed something?


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From: Robert McGregor
Subject: Re: A light bulb
Date: 21 Feb 2011 01:30:01
Message: <web.4d61bf6d94c155b694d713cc0@news.povray.org>
"alanr" <nomail@nomail> wrote:
> Apologies if this has been understood by others but an explanation I just read
> seemed so simple I'm baffled it does not quite work as expected.
>
> In Moray I created a csg union of a point light with a sphere and created a
> whiteish material with a finish ambient set to 1, and sphere set no shadow.  But
> it renders black, albeit light appears to emit from this object.
>
> Have to turn the scene ambient up full in order to make the sphere look like its
> lit, but this of course a produces general glow to all objects from an unseen
> source which I dont really want.
>
> Is setting the scene ambient to 1 the only way to get the sphere to "glow" or
> have I missed something?

If you're using radiosity then try emissive instead of ambient.

-------------------------------------------------
www.McGregorFineArt.com


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From: Stephen
Subject: Re: A light bulb
Date: 21 Feb 2011 10:47:53
Message: <4d6242d9$1@news.povray.org>
On 21/02/2011 1:22 AM, alanr wrote:
> Is setting the scene ambient to 1 the only way to get the sphere to "glow" or
> have I missed something?

What I think you are looking for is projected_through to allow light 
through an object without the object casting a shadow. Or looks_like to 
make a light source have the appearance of an object. Neither of which 
seem to be available in Moray. I stopped using Moray a few years ago and 
now use Bishop3D as is still being developed and works with PovRay 3.7.
The other way of doing it is to use “Direct Code” in the Material editor.
Firstly create a material called Material1 with direct code texture. 
Paste the code below into the “Direct Code”.
Then create a union of a sphere and point light. Assign Material1 to the 
sphere. You can change how translucent the sphere is by changing the 
diffuse value of interior_texture and change the ambient in the 
interior_texture as well. (I’ve marked both and they are near the end of 
the code.

Code below (watch out for line breaks):

#declare Material1 =
material{
   texture {
     pigment {
       colour rgbft <1.000,1.000,1.000,0.000,1.000>
     }

     finish {
       ambient     rgb <0.00,0.00,0.00>
       brilliance  1.000
       crand       0.000
       diffuse     1.000
       metallic    0.000
       phong       0.000
       phong_size  40.000
       specular    0.200
       roughness   0.050
       reflection {
         rgb <0.200,0.200,0.200>, rgb <0.100,0.100,0.100>
         fresnel   0
         falloff   0.000
         exponent  1.000
         metallic  0.000
       }

     }

   }

   interior_texture {
     pigment {
       colour rgbft <1.000,1.000,1.000,0.100,0.000>
     }

     normal {
       leopard, 0.100
       scale     <0.001,0.001,0.001>
       scale     <0.001,0.001,0.001>
       warp {
         turbulence <5.000,5.000,5.000>
         octaves 6
         lambda 2.000
         omega 0.500
       }
     }

     finish {
       ambient     rgb <0.700,0.700,0.700> /* Change this overall 
brightness */
       brilliance  1.000
       crand       0.000
       diffuse     0.210	/* Change this for amount  of transparency */
       metallic    0.000
       phong       0.000
       phong_size  1.000
       specular    0.000
       roughness   0.001
       reflection {
         rgb <0.000,0.000,0.000>, rgb <0.000,0.000,0.000>
         fresnel   0
         falloff   0.000
         exponent  1.000
         metallic  0.000
       }
     }

   }

}


-- 
Regards
     Stephen


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From: alanr
Subject: Re: A light bulb
Date: 21 Feb 2011 13:30:01
Message: <web.4d62685394c155b61d72ddf90@news.povray.org>
"Robert McGregor" <rob [at] mcgregorfineartcom> wrote:
> "alanr" <nomail@nomail> wrote:
> > Apologies if this has been understood by others but an explanation I just read
> > seemed so simple I'm baffled it does not quite work as expected.
> >
> > In Moray I created a csg union of a point light with a sphere and created a
> > whiteish material with a finish ambient set to 1, and sphere set no shadow.  But
> > it renders black, albeit light appears to emit from this object.
> >
> > Have to turn the scene ambient up full in order to make the sphere look like its
> > lit, but this of course a produces general glow to all objects from an unseen
> > source which I dont really want.
> >
> > Is setting the scene ambient to 1 the only way to get the sphere to "glow" or
> > have I missed something?
>
> If you're using radiosity then try emissive instead of ambient.
>
> -------------------------------------------------
> www.McGregorFineArt.com

Hi Robert - thanks for your speedy reply - I must be having a senior moment as I
could not figure out how to get what I was after by trying that.  I assume it
was a good suggestion, but my understanding of radiosity matters is very
limited, but your feedback was appreciated.


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From: alanr
Subject: Re: A light bulb
Date: 21 Feb 2011 13:40:00
Message: <web.4d626a3394c155b61d72ddf90@news.povray.org>
Stephen <mcavoys_at@aoldotcom> wrote:
> On 21/02/2011 1:22 AM, alanr wrote:
> > Is setting the scene ambient to 1 the only way to get the sphere to "glow" or
> > have I missed something?
>
> What I think you are looking for is projected_through to allow light
> through an object without the object casting a shadow. Or looks_like to
> make a light source have the appearance of an object. Neither of which
> seem to be available in Moray. I stopped using Moray a few years ago and
> now use Bishop3D as is still being developed and works with PovRay 3.7.
> The other way of doing it is to use “Direct Code” in the Material editor.
> Firstly create a material called Material1 with direct code texture.
> Paste the code below into the “Direct Code”.
> Then create a union of a sphere and point light. Assign Material1 to the
> sphere. You can change how translucent the sphere is by changing the
> diffuse value of interior_texture and change the ambient in the
> interior_texture as well. (I’ve marked both and they are near the end of
> the code.
>
> Code below (watch out for line breaks):
>
> code removed to save space>
>
> --
> Regards
>      Stephen

Thanks for your speedy reply Stephen - but I followed your guidance to the
letter and got a reasonable result, especially when I cranked up the ambient to
1,1,1 and diffuse to 1.  Not sure I fully understand the detail of the code but
thats why I use Moray.

But your solution works which is what matters, and for that I'm grateful.

Now going to post another very fundamental question on reflection.


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From: Stephen
Subject: Re: A light bulb
Date: 21 Feb 2011 16:58:16
Message: <4d6299a8$1@news.povray.org>
On 21/02/2011 1:35 PM, alanr wrote:
> Thanks for your speedy reply Stephen - but I followed your guidance to the
> letter and got a reasonable result, especially when I cranked up the ambient to
> 1,1,1 and diffuse to 1.

I’m not sure I understand it completely myself. I got some advice from 
Alain in the p.binary.images group.

> Not sure I fully understand the detail of the code but
> thats why I use Moray.
>

That’s one of the reasons I started to use Moray. That and the fact I’m 
not very good at visualising scenes.
But it is not a bad idea to be able to read and write some code.
I took Lutz’s advice and spent a couple of weeks playing with PovRay 
before using Moray heavily.

> But your solution works which is what matters, and for that I'm grateful.
>

My pleasure. I’ve not used Moray for ages (partly because it only really 
works with Ver 3.5)

> Now going to post another very fundamental question on reflection.

I’ll let the big brains confuse you. BTW “using photons” is the way to 
go. ;-)

-- 
Regards
     Stephen


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