Am 08.03.2013 07:53, schrieb s.day:

> Even after all this time I still have plenty to learn, I am obviously a slow
> learner though ;-)

There is /nobody/ around these forums who knows everything about 
POV-Ray. The current dev team included.

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clipka <ano### [at] anonymousorg> wrote:
> With metallic surfaces you do not have any scattering within the
> material - instead, any diffuse-style reflection is the result of
> repeated specular reflection at a very clustered surface. I wouldn't be
> surprised if this indeed results in quite different characteristics. My
> first guess, however, would be that those characteristics would be more
> faithfully modelled with a very rough specular highlight, rather than a
> high-brilliance diffuse term.

You may be right.  I just had a look at some diffuse metallic surfaces, and the
effect I attributed to brilliance depends on viewing angle.  That is highly
suggestive of a very broad highlight, rather than diffuse reflection.

Of course, to model this requires S+P > R, because for a diffuse surface, R = 0!
This requires more thought and experimentation.

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Am 08.03.2013 17:53, schrieb Cousin Ricky:

> You may be right.  I just had a look at some diffuse metallic surfaces, and the
> effect I attributed to brilliance depends on viewing angle.  That is highly
> suggestive of a very broad highlight, rather than diffuse reflection.
>
> Of course, to model this requires S+P > R, because for a diffuse surface, R = 0!
> This requires more thought and experimentation.

In POV-Ray practice, yes. Theoretically we'd still need S+P=R with R>0, 
albeit with a good deal of blur.

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"Cousin Ricky" <rickysttATyahooDOTcom> wrote:
> You may be right.  I just had a look at some diffuse metallic surfaces, and the
> effect I attributed to brilliance depends on viewing angle.  That is highly
> suggestive of a very broad highlight, rather than diffuse reflection.

You know, it's really, really difficult to find truly diffuse metallic objects.
There are plenty of objects with highly blurred reflection, but not blurred
enough for me to consider "diffuse."  The only satisfactory examples I can find
have no curved surfaces and are nailed to the wall.  It's hard to examine
reflective effects of such objects.

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Am 08.03.2013 18:52, schrieb Cousin Ricky:
> "Cousin Ricky" <rickysttATyahooDOTcom> wrote:
>> You may be right.  I just had a look at some diffuse metallic surfaces, and the
>> effect I attributed to brilliance depends on viewing angle.  That is highly
>> suggestive of a very broad highlight, rather than diffuse reflection.
>
> You know, it's really, really difficult to find truly diffuse metallic objects.
> There are plenty of objects with highly blurred reflection, but not blurred
> enough for me to consider "diffuse."  The only satisfactory examples I can find
> have no curved surfaces and are nailed to the wall.  It's hard to examine
> reflective effects of such objects.

Let alone that such diffuse-looking specimen of metal typically don't 
really have a metallic surface anymore, but a metal oxide one.

Sintered metal does seem to do the trick though, depending on how porous 
it is - sintered metal filters, for instance. Judging from images found 
on the internet, I'd guestimate such materials to exhibit a brilliance 
of 1.0 - or maybe even lower.

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clipka <ano### [at] anonymousorg> wrote:
> Am 08.03.2013 18:52, schrieb Cousin Ricky:
> > You know, it's really, really difficult to find truly diffuse metallic objects.
> > There are plenty of objects with highly blurred reflection, but not blurred
> > enough for me to consider "diffuse."  The only satisfactory examples I can find
> > have no curved surfaces and are nailed to the wall.  It's hard to examine
> > reflective effects of such objects.
>
> Let alone that such diffuse-looking specimen of metal typically don't
> really have a metallic surface anymore, but a metal oxide one.
>
> Sintered metal does seem to do the trick though, depending on how porous
> it is - sintered metal filters, for instance. Judging from images found
> on the internet, I'd guestimate such materials to exhibit a brilliance
> of 1.0 - or maybe even lower.

What I've found are:
  - a galvanized plate--my guess is the back plate of an electrical outlet
    box that was never installed
  - brass shelf structures, no patina
  - shelf supports of probably aluminum or white metal.

My windows have non-specular metal louvers, but the surface finish is absolutely
non-metallic.

In places other than my home, I've seen railings, plumbing fittings, and
(possibly) door handles that fit the bill.

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A couple more renders with the correct settings and a different .hdr file.

I could render these all day (literally).

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Attachments:
Download 'lantern_aennis1.png' (330 KB)

Preview of image 'lantern_aennis1.png'

And again...

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Attachments:
Download 'lantern_aennis_2.png' (280 KB)

Preview of image 'lantern_aennis_2.png'

>s.day  on date 09/03/2013 2.13 wrote:
> And again...
>
It's a very nice work. It remembers me of elder days...
Paolo

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Paolo Gibellini <p.g### [at] gmailcom> wrote:
> >s.day  on date 09/03/2013 2.13 wrote:
> > And again...
> >
> It's a very nice work. It remembers me of elder days...
> Paolo

Thanks, I am just trying to get back into using POV after not doing much with it
over the last few years. This is part of a small scene I have been working on
for a while and I thought it would be a good subject for an HDR render.

the lantern is all CSG, some of the details are not that accurate (you could
call it artistic license but really it is laziness ;-).

Sean

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