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From: David Kraics
Subject: shiny plastic
Date: 13 Oct 2018 01:20:00
Message: <web.5bc148031a2fa99d749dac470@news.povray.org>
Can anyone suggest a good finish to render a television that has the "shiny
plastic" on the front? I tried the finishes in the metals.inc file but they
reflect too well.


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From: Alain
Subject: Re: shiny plastic
Date: 13 Oct 2018 03:41:59
Message: <5bc16987$1@news.povray.org>
Le 18-10-12 à 21:18, David Kraics a écrit :
> Can anyone suggest a good finish to render a television that has the "shiny
> plastic" on the front? I tried the finishes in the metals.inc file but they
> reflect too well.
> 
> 

The finishes from metals.inc are only to be used to model metallic 
surfaces. They are not realist for plastics, paints and varnishes or 
liquids like water.

The reflection from plastics are not constant, they respect the fresnel 
equation.
So, you need to :
1) Use the fresnel in the finish :
  finish{[Finish_Items] reflection{Max_Reflection 
fresnel}[[conserve_energy] More_Finish_Items]}
«conserve_energy» is only needed for transparent surfaces.

2) Add an interior block where you set an ior. It should be in the 1.4 
to 1.7 range. Example :
  interior{ior 1.5 [dispersion Dispersion_Value]}

Having an ior do not require that you have any transparency.
Adding some dispersion can slightly affect the aspect of the surface and 
make the reflection very slightly bluer, unless you use some insane 
dispersion amount.


Alain


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From: Bald Eagle
Subject: Re: shiny plastic
Date: 13 Oct 2018 13:35:00
Message: <web.5bc1f426674b8662458c7afe0@news.povray.org>
"David Kraics" <bar### [at] aolcom> wrote:
> Can anyone suggest a good finish to render a television that has the "shiny
> plastic" on the front? I tried the finishes in the metals.inc file but they
> reflect too well.

A super quick way to get that "plastic look" is to just add some specular
reflection to your texture.

texture {pigment {Blue} finish {specular 0.4}} will give you that shiny look.

from there you can adjust that, and add the reflection keyword to the finish
block - because I'm speculating that your TV is black plastic.

And if you really want to see a big change in how your texture looks - don't
fiddle with the texture, change what's _around it_ since it has a huge effect on
the reflective surface.

A very quick way to get rather astonishing results is just to use an HDRI light
probe (downloadable for free on the web) and some radiosity.   There's an
include file - rad_def.inc in the POV-Ray distribution that you can use.


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From: Stephen
Subject: Re: shiny plastic
Date: 13 Oct 2018 19:05:00
Message: <5bc241dc$1@news.povray.org>
On 13/10/2018 14:33, Bald Eagle wrote:
> "David Kraics" <bar### [at] aolcom> wrote:
>> Can anyone suggest a good finish to render a television that has the "shiny
>> plastic" on the front? I tried the finishes in the metals.inc file but they
>> reflect too well.
> 
> A super quick way to get that "plastic look" is to just add some specular
> reflection to your texture.
> 
> texture {pigment {Blue} finish {specular 0.4}} will give you that shiny look.
> 

Good advice from Alain and Bald Eagle.
I generally have the oposite problem. Making an object not look like 
plastic. :)

> from there you can adjust that, and add the reflection keyword to the finish
> block - because I'm speculating that your TV is black plastic.
> 

Don't start with a reflection value of 1 but start low and work your way 
up. I find it easier to see the differences that way.


> And if you really want to see a big change in how your texture looks - don't
> fiddle with the texture, change what's _around it_ since it has a huge effect on
> the reflective surface.
> 

This is so true for any scene that has reflective objects.


> A very quick way to get rather astonishing results is just to use an HDRI light
> probe (downloadable for free on the web) and some radiosity.   There's an
> include file - rad_def.inc in the POV-Ray distribution that you can use.
> 
>

Bald Eagle is right but I would leave the radiosity to the end of 
building your scene as it can add quite a bit of time to the rendering.

For testing your TV material. Create a sphere with a no image flag. This 
will allow the reflections of the sphere to be shown in the reflections 
of your TV. Convert a HDRi to a png and create a material using this and 
attach it to the sphere. The reflections should show up.
Aside, some HDR images are in a cruciform format which should be used 
with a box not a sphere.

You can download some HDRIs from here:
https://hdrihaven.com/hdris/category/?c=all



> 
> 


-- 

Regards
     Stephen


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From: Alain
Subject: Re: shiny plastic
Date: 14 Oct 2018 15:54:37
Message: <5bc366bd$1@news.povray.org>
Le 18-10-13 à 15:04, Stephen a écrit :
> On 13/10/2018 14:33, Bald Eagle wrote:
>> "David Kraics" <bar### [at] aolcom> wrote:
>>> Can anyone suggest a good finish to render a television that has the 
>>> "shiny
>>> plastic" on the front? I tried the finishes in the metals.inc file 
>>> but they
>>> reflect too well.
>>
>> A super quick way to get that "plastic look" is to just add some specular
>> reflection to your texture.
>>
>> texture {pigment {Blue} finish {specular 0.4}} will give you that 
>> shiny look.
>>
> 
> Good advice from Alain and Bald Eagle.
> I generally have the oposite problem. Making an object not look like 
> plastic. :)
> 
>> from there you can adjust that, and add the reflection keyword to the 
>> finish
>> block - because I'm speculating that your TV is black plastic.
>>
> 
> Don't start with a reflection value of 1 but start low and work your way 
> up. I find it easier to see the differences that way.
> 
> 
>> And if you really want to see a big change in how your texture looks - 
>> don't
>> fiddle with the texture, change what's _around it_ since it has a huge 
>> effect on
>> the reflective surface.
>>
> 
> This is so true for any scene that has reflective objects.
> 
> 
>> A very quick way to get rather astonishing results is just to use an 
>> HDRI light
>> probe (downloadable for free on the web) and some radiosity.   There's an
>> include file - rad_def.inc in the POV-Ray distribution that you can use.
>>
>>
> 
> Bald Eagle is right but I would leave the radiosity to the end of 
> building your scene as it can add quite a bit of time to the rendering.
> 
> For testing your TV material. Create a sphere with a no image flag. This 
> will allow the reflections of the sphere to be shown in the reflections 
> of your TV. Convert a HDRi to a png and create a material using this and 
> attach it to the sphere. The reflections should show up.
> Aside, some HDR images are in a cruciform format which should be used 
> with a box not a sphere.
> 
> You can download some HDRIs from here:
> https://hdrihaven.com/hdris/category/?c=all
> 
> 

There is no need to convert the HDRI to any other format as HDRI is 
directly supported in version 3.7 and later. You can use *.HDR or *.EXR 
files.

For a rectangular longitude-latitude image :
sphere{0 Radius pigment{image_map{ hdr "Name.hrd" map_type 1 interpolate 
1} scale <-1,1,1>}finish{diffuse 0 emission 1}}

The scale is to flip the image so that it show in the correct direction 
from the inside of the sphere.
Some probes may be to bright or dim. Adjust emission to get correct results.



Alain


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From: Stephen
Subject: Re: shiny plastic
Date: 14 Oct 2018 17:25:10
Message: <5bc37bf6@news.povray.org>
On 14/10/2018 16:55, Alain wrote:
> Le 18-10-13 à 15:04, Stephen a écrit :
>> For testing your TV material. Create a sphere with a no image flag. 
>> This will allow the reflections of the sphere to be shown in the 
>> reflections of your TV. Convert a HDRi to a png and create a material 
>> using this and attach it to the sphere. The reflections should show up.
>> Aside, some HDR images are in a cruciform format which should be used 
>> with a box not a sphere.
>>
>> You can download some HDRIs from here:
>> https://hdrihaven.com/hdris/category/?c=all
>>
>>
> 
> There is no need to convert the HDRI to any other format as HDRI is 
> directly supported in version 3.7 and later. You can use *.HDR or *.EXR 
> files.
> 
> For a rectangular longitude-latitude image :
> sphere{0 Radius pigment{image_map{ hdr "Name.hrd" map_type 1 interpolate 
> 1} scale <-1,1,1>}finish{diffuse 0 emission 1}}
> 
> The scale is to flip the image so that it show in the correct direction 
> from the inside of the sphere.
> Some probes may be to bright or dim. Adjust emission to get correct 
> results.
> 
> 


Of course you are right. I am still, mostly, using Pov ver 3.62 SDL.
I really look forward to the news before the end of the year. :)

Apologies to David but the point still stands. Radiosity is a subject in 
itself and takes time. In my opinion.

-- 

Regards
     Stephen


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From: Thomas de Groot
Subject: Re: shiny plastic
Date: 15 Oct 2018 06:30:47
Message: <5bc43417$1@news.povray.org>
On 14-10-2018 19:25, Stephen wrote:
> On 14/10/2018 16:55, Alain wrote:
>> Le 18-10-13 à 15:04, Stephen a écrit :
>>> For testing your TV material. Create a sphere with a no image flag. 
>>> This will allow the reflections of the sphere to be shown in the 
>>> reflections of your TV. Convert a HDRi to a png and create a material 
>>> using this and attach it to the sphere. The reflections should show up.
>>> Aside, some HDR images are in a cruciform format which should be used 
>>> with a box not a sphere.
>>>
>>> You can download some HDRIs from here:
>>> https://hdrihaven.com/hdris/category/?c=all
>>>
>>>
>>
>> There is no need to convert the HDRI to any other format as HDRI is 
>> directly supported in version 3.7 and later. You can use *.HDR or 
>> *.EXR files.
>>
>> For a rectangular longitude-latitude image :
>> sphere{0 Radius pigment{image_map{ hdr "Name.hrd" map_type 1 
>> interpolate 1} scale <-1,1,1>}finish{diffuse 0 emission 1}}
>>
>> The scale is to flip the image so that it show in the correct 
>> direction from the inside of the sphere.
>> Some probes may be to bright or dim. Adjust emission to get correct 
>> results.
>>
>>
> 
> 
> Of course you are right. I am still, mostly, using Pov ver 3.62 SDL.
> I really look forward to the news before the end of the year. :)
> 
> Apologies to David but the point still stands. Radiosity is a subject in 
> itself and takes time. In my opinion.
> 

One can diverge on this though ;-) In most if not all of my scenes, I 
have radiosity switched on from the start, and I rarely change the 
settings, with the exception of recursion_limit, media, and normal, 
which I adapt to the needs specific of my scene. See a sample xode 
example below (watch out for line breaks when copying):

   radiosity {
     pretrace_start 0.08           // start pretrace at this size
     pretrace_end   0.004          // end pretrace at this size
     count 50, 1000                // higher -> higher quality (1..1600) 
[35]
     nearest_count 10, 5           // higher -> higher quality (1..10) [5]
     error_bound 1                 // higher -> smoother, less accurate 
[1.8]
     recursion_limit 2             // how much interreflections are 
calculated (1..5+) [2]
     low_error_factor .3           // reduce error_bound during last 
pretrace step
     gray_threshold 0.0            // increase for weakening colors 
(0..1) [0]
     minimum_reuse 0.015           // reuse of old radiosity samples [0.015]
     maximum_reuse 0.1							    brightness 1                  // 
brightness of radiosity effects (0..1) [1]

     adc_bailout 0.01/2
     normal off                   // take surface normals into account [off]
     media off                    // take media into account [off]
     always_sample off           // turn sampling in final trace off [on]
     //max_sample 1.0              // maximum brightness of samples
   }


-- 
Thomas


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From: Stephen
Subject: Re: shiny plastic
Date: 15 Oct 2018 08:55:44
Message: <5bc45610@news.povray.org>
On 15/10/2018 07:30, Thomas de Groot wrote:
>>
>> Apologies to David but the point still stands. Radiosity is a subject 
>> in itself and takes time. In my opinion.
>>
> 
> One can diverge on this though ;-) In most if not all of my scenes, I 
> have radiosity switched on from the start, and I rarely change the 
> settings, with the exception of recursion_limit, media, and normal, 
> which I adapt to the needs specific of my scene. See a sample xode 
> example below (watch out for line breaks when copying):

But you have been using PovRay for decades and might be described as a 
bit of an expert. :-)
And life has shown me that you should only change one thing at a time. 
The first thing I would do is to add something to show the reflections. 
Then work on the materials, leaving radiosity to the end.



-- 

Regards
     Stephen


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From: Thomas de Groot
Subject: Re: shiny plastic
Date: 15 Oct 2018 11:03:21
Message: <5bc473f9@news.povray.org>
On 15-10-2018 10:55, Stephen wrote:
> On 15/10/2018 07:30, Thomas de Groot wrote:
>>>
>>> Apologies to David but the point still stands. Radiosity is a subject 
>>> in itself and takes time. In my opinion.
>>>
>>
>> One can diverge on this though ;-) In most if not all of my scenes, I 
>> have radiosity switched on from the start, and I rarely change the 
>> settings, with the exception of recursion_limit, media, and normal, 
>> which I adapt to the needs specific of my scene. See a sample xode 
>> example below (watch out for line breaks when copying):
> 
> But you have been using PovRay for decades and might be described as a 
> bit of an expert. :-)
> And life has shown me that you should only change one thing at a time. 
> The first thing I would do is to add something to show the reflections. 
> Then work on the materials, leaving radiosity to the end.
> 

I bow to the wisdom of your age, against the rashness of my doting 
years. :-)


-- 
Thomas


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From: Stephen
Subject: Re: shiny plastic
Date: 15 Oct 2018 11:49:48
Message: <5bc47edc$1@news.povray.org>
On 15/10/2018 12:03, Thomas de Groot wrote:
> On 15-10-2018 10:55, Stephen wrote:
>> On 15/10/2018 07:30, Thomas de Groot wrote:
>>>>
>>>> Apologies to David but the point still stands. Radiosity is a 
>>>> subject in itself and takes time. In my opinion.
>>>>
>>>
>>> One can diverge on this though ;-) In most if not all of my scenes, I 
>>> have radiosity switched on from the start, and I rarely change the 
>>> settings, with the exception of recursion_limit, media, and normal, 
>>> which I adapt to the needs specific of my scene. See a sample xode 
>>> example below (watch out for line breaks when copying):
>>
>> But you have been using PovRay for decades and might be described as a 
>> bit of an expert. :-)
>> And life has shown me that you should only change one thing at a time. 
>> The first thing I would do is to add something to show the 
>> reflections. Then work on the materials, leaving radiosity to the end.
>>
> 
> I bow to the wisdom of your age, against the rashness of my doting 
> years. :-)
> 
> 

My clue was the name of the forum. :-)

All the advice including your settings are good.

-- 

Regards
     Stephen


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