> Alain <kua### [at] videotronca> wrote:
>> Looks like your shades may not let the light pass through, or maybe the
>> lights are accidently located inside an opaque part of your fixtures.
>
> I have the point light sources moved to the proper positions now, what I need to
> do is give the impression that there is actually a light THERE - not necessarily
> a filament, but that radiating glow that emanates out through the glass.
> My knee-jerk reaction is to incorporate media...

No need for media.
If using radiosity, a look_like sphere, or any shape you may want, with 
an emissive finish will do.
Another way would be to use the back side illumination feature. Simply 
adding a second value to the diffuse parameter turn that on. (diffuse 
0.1 0.7 will diffuse mostly from the back side) Works great with radiosity.

If using photons, beter add photons{pass_through} to the fixture.

...
> Off to make adjustments and render it out again...
>

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Alain <kua### [at] videotronca> wrote:

> No need for media.
> If using radiosity, a look_like sphere, or any shape you may want, with
> an emissive finish will do.
> Another way would be to use the back side illumination feature. Simply
> adding a second value to the diffuse parameter turn that on. (diffuse
> 0.1 0.7 will diffuse mostly from the back side) Works great with radiosity.

Well, I modeled a bulb with a filament, and it looks ok in the include file
render.  Replacing the point light sources with these bulbs gives me --- eeek.


Here's my lampshade glass:

  //  Glass
  difference {
   cone {<0, 0, 0>, 1.95, <0, 4.625, 0>, 3.875}
   cone {<0, 0, 0>, 1.95, <0, 4.625, 0>, 3.875 scale <0.9, 1.2, 0.9>}
   translate < 7.687, 0.4375, 0>
   interior {ior 1.5}
   texture {pigment {rgbt <1, 0.7, 0, 0.9>} finish {emission 0.7}}
   double_illuminate
   }

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Attachments:
Download 'oldlightbulb.png' (30 KB)

Preview of image 'oldlightbulb.png'

Here's my WIP lightbulb include file - I want to make a little point of glass at
the top like an old-time hand-blown bulb...  blob?

(Screw base is borrowed from
// Persistence of Vision Ray Tracer Scene Description File
// File: bulbsokt.pov
// Vers: 3.1
// Desc: Item in "Household fixtures" series
// Date: 7OCT2000
// Auth: James R. Wilson jwi### [at] twcnyrrcom
//
// A standard light bulb and a porcelain socket
// Scale: decimal inches
)

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Attachments:
Download 'oldlightbulb.inc.txt' (8 KB)

I'm gonna guess that this is a max trace level issue...

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Attachments:
Download 'secretpassage.png' (263 KB)

Preview of image 'secretpassage.png'

On 4-11-2014 4:12, Bald Eagle wrote:
> I'm gonna guess that this is a max trace level issue...
>

But radiosity is switched off in this scene surely??

Thomas

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Thomas de Groot <tho### [at] degrootorg> wrote:
> On 4-11-2014 4:12, Bald Eagle wrote:
> > I'm gonna guess that this is a max trace level issue...
> >
>
> But radiosity is switched off in this scene surely??
>
> Thomas

It surely was, but enabling it didn't do much except add a bit of "fill light"
to the dark region.  I'm no longer sure it's a max_trace_level thing, since I
commented out the glass of the bulb, and raise MTL from 5 to 7 ....  Must have
something to do with the looks_like {Filament}?

I've only ever tried using light bulbs or looks_like a few times before, and
it's always a frustrating experience.

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On 4-11-2014 14:04, Bald Eagle wrote:
> Thomas de Groot <tho### [at] degrootorg> wrote:
>> On 4-11-2014 4:12, Bald Eagle wrote:
>>> I'm gonna guess that this is a max trace level issue...
>>>
>>
>> But radiosity is switched off in this scene surely??
>>
>> Thomas
>
> It surely was, but enabling it didn't do much except add a bit of "fill light"
> to the dark region.  I'm no longer sure it's a max_trace_level thing, since I
> commented out the glass of the bulb, and raise MTL from 5 to 7 ....  Must have
> something to do with the looks_like {Filament}?

Not necessarily the look_like, I suspect it might be the light bulbs 
themselves. Why not just go with simple lights, without any bulb around 
them? They will not be visible once the shades are in place. If that 
works, you can add looks_likes represented by simple small spheres with 
high emission. I think wanting to model the bulbs is overkill in this scene.

Thomas

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On 04/11/2014 03:12, Bald Eagle wrote:
> I'm gonna guess that this is a max trace level issue...
>

What does it look like without the isosurfaces?

I have tried a couple of times to use ceiling lamps with the lamp holder 
at the bottom. And always had similar results to yours. But since I 
don’t use radiosity, ambient gets round the lack of atmospheric scattering.
Have you thought of changing the light fitting to one where the holder 
is above the bulb? Like one of these:

http://tinyurl.com/qx2kh9g
http://tinyurl.com/ls9klmy

These may be more in keeping with your room.

http://tinyurl.com/k3yda65
http://tinyurl.com/kb72lgd


-- 

Regards
     Stephen

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Stephen <mca### [at] aolcom> wrote:

> What does it look like without the isosurfaces?

There's not a single isosurface in the scene.  I figured it might have something
to do with going through the bulb glass, then the lampshade glass, but I get the
same effect when I just use a looks_like {sphere}....

> I have tried a couple of times to use ceiling lamps with the lamp holder
> at the bottom. And always had similar results to yours.

It's not the ceiling fixture, since the other images I posted have point light
sources in the exact same places in the fixture, and they light up the whole
scene just fine.   All I get are the shadows that jhu didn't like.

> But since I
> don't use radiosity, ambient gets round the lack of atmospheric scattering.
> Have you thought of changing the light fitting to one where the holder
> is above the bulb?

I have, though as I mentioned, the fixture doesn't seem to be the issue.
The lighting and the radiosity seem to all work fine, I'm just trying to work
out how to get the fixture to have a visible light source - but I'm getting both
this weird cut-off effect (which doesn't make sense if you draw a line from near
the top of the lampshade to the edge of the metal fixture - it should intersect
the wall somewhere low, not look like some sort of water_level height_field
cutoff) and the glowing sphere that seems to work well in the lightbulb WIP
looks like a grayish sphere suspended inside the lampshade.

I'm puzzled by this, though I am often thwarted by seemingly simple and
otherwise-straightforward tasks....

I can post the source if it helps hunt down the issue, and you can see that the
fixture-under-lamp doesn't mess up the scene - something else does.

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> Thomas de Groot <tho### [at] degrootorg> wrote:
>> On 4-11-2014 4:12, Bald Eagle wrote:
>>> I'm gonna guess that this is a max trace level issue...
>>>
>>
>> But radiosity is switched off in this scene surely??
>>
>> Thomas
>
> It surely was, but enabling it didn't do much except add a bit of "fill light"
> to the dark region.  I'm no longer sure it's a max_trace_level thing, since I
> commented out the glass of the bulb, and raise MTL from 5 to 7 ....  Must have
> something to do with the looks_like {Filament}?
>
> I've only ever tried using light bulbs or looks_like a few times before, and
> it's always a frustrating experience.
>

Try max_trace_level 255. If the isue is still there, then, it's probably 
something else.

In this scene, I'd forget modeling the whole bulb and only use a small 
sphere with looks_like. Anyway, the bulbs are realy small compared to 
the rest. Only resort to the fully modelled bulbs if you ever render a 
close up view of the chandelier or the fixtures.

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