POV-Ray : Newsgroups : povray.binaries.images : Flexible lamp neck : Re: Flexible lamp neck Server Time
24 May 2022 11:28:16 EDT (-0400)
  Re: Flexible lamp neck  
From: Cousin Ricky
Date: 21 Feb 2021 00:08:08
Message: <6031eab8$1@news.povray.org>
On 2021-02-20 7:24 PM (-4), Bald Eagle wrote:
> Cousin Ricky <ric### [at] yahoocom> wrote:
>> Sneak preview.  The harlequin colors are there for testing.
>> That other lamp in the left background is a rudimentary place holder
>> that I've been using for the past 5 years.
> Well, you've certainly spent a lot of time honing this object.
> The textures are very nice, and they really replicate the real thing.
> The base just looks - real.  The shape, the gloss, the texture on the toggle
> switch, the press-fitting of the lamp neck.  Even the little gap between the
> base and the floor, where the felt pad presumably is.

That _is_ the felt (or rubber) pad.  It's just dark like a shadow.

> The light bulb looks real as well.  I looks like thin glass with a thin layer of
> kaolin powder coated onto the inside.

This was a v3.7 render, so I used a layered texture in lieu of 
finish-level Fresnel.  The material macro autodetects v3.8 and would 
just go straight for the finish-level Fresnel, but you have me wondering 
if I should bother.  When I look at a frosted bulb IRL (actually, an LED 
lookalike), it looks like there's some SSLT going on there, but I wasn't 
going to bother with it.  Maybe the layered texture looks more realistic 
than the finish-level Fresnel?

> It's neat that the texture on the outside of the shade "peeks out" a bit beyond
> the inner white.

That's a happy side effect of an attempt to avoid the radiosity 
artifacts that would otherwise manifest when the lamp is switched on. 
When I first coded the place holders, I ended up with nasty white spots 
all over my render rig until I set no_radiosity on the fixtures.  But I 
only want to do this for the inside of the hood.

> Should be interesting to see your power cord, and the lit final product.

The power cord is still in my "future plans" bin.  I'm thinking about 
commandeering the Rope module from the object collection, as it may have 
already solved the issues that will certainly turn up.  My biggest 
concern here is the plug: different countries have different standards, 
and I'm wondering if the plug should be its own module with 
international options.

> Of course you're going to want to give the neck spline a bit of non-uniform
> wiggle, and from a math and rigging perspective, one would have to define a
> minimum radius that the FMC/Greenfield style neck can achieve and somehow
> disallow sharper bends.  Just a math/programming observation and a puzzle to
> suggest.  :)

A minimum radius will naturally fall out of the constraints that I put 
in the lamp macro.  I'm glad you're going to work on the wiggle.  ;)

> Your placeholder has that antialiasing artifact that just got brought up.

Yes, it is creepy, but I explained why I'd rather live with it.

> The square in front of it is rather bright - a trick of the lighting and
> falloff?

Yes, that's exactly what that is.  The light source uses the bulb radius 
as its fade distance, which results in very bright illumination near the 
light, and a rapid falloff as the distance increases.  If you look 
carefully, you'll notice that the dark squares closest to the lamp are 
also somewhat lighter.

> That thing is gonna look _real_ with an HDR environment.   :O
That's half the intention.

Notice the flying saucer shaped reflection in the blue stripe of the 
hood: that is the distorted reflection of a second place holder lamp 
outside the right of the frame.  Only with hyper-white illumination can 
such a reflection be realistic.  Even so, the light is only 10% of 
normal brightness, because I'm only using it as a fill.  (The visible 
place holder is also a fill.  The main light source happens not to be 
reflected anywhere.)

One problem that concerns me is reflections of lit bulbs.  If the 
reflecting surface has a specular or Phong highlight, you end up with 
twice the reflected light.  For this render environment, I tentatively 
solved this by setting no_reflection on the place holder's bulb, but 
this results in a highlight that doesn't reflect the extent of the bulb. 
  When I release the source code for the lamp, there will be a parameter 
to turn the reflection on or off, and let the user decide what to do 
with highlights--unless someone has a better idea.

> As always, very nice, very meticulous work.


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