POV-Ray : Newsgroups : povray.binaries.images : Testing ... Server Time: 29 Jun 2017 12:25:21 GMT
  Testing ... (Message 1 to 9 of 9)  
From: Jim Holsenback
Subject: Testing ...
Date: 11 Apr 2017 12:28:30
Message: <58eccbee@news.povray.org>
... these 3.7.1 features. All materials have the finish level fresnel. 
The key light uses the new light fading model. Used type 7 image map 
with the hdr probe surrounding everything and last but not least tau is 
used to position the camera and light source.


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flowers.png


 

From: Thomas de Groot
Subject: Re: Testing ...
Date: 12 Apr 2017 06:56:35
Message: <58edcfa3$1@news.povray.org>
On 11-4-2017 14:28, Jim Holsenback wrote:
> ... these 3.7.1 features. All materials have the finish level fresnel.
> The key light uses the new light fading model. Used type 7 image map
> with the hdr probe surrounding everything and last but not least tau is
> used to position the camera and light source.

Interesting, although I miss a bit of highlights on leaves and petals. 
They seem a bit flat.

-- 
Thomas


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From: Jim Holsenback
Subject: Re: Testing ...
Date: 12 Apr 2017 11:10:50
Message: <58ee0b3a$1@news.povray.org>
On 4/12/2017 2:56 AM, Thomas de Groot wrote:
> On 11-4-2017 14:28, Jim Holsenback wrote:
>> ... these 3.7.1 features. All materials have the finish level fresnel.
>> The key light uses the new light fading model. Used type 7 image map
>> with the hdr probe surrounding everything and last but not least tau is
>> used to position the camera and light source.
>
> Interesting, although I miss a bit of highlights on leaves and petals.
> They seem a bit flat.
>
yeah i know what you mean ... it's the fresnel. perhaps a misuse for 
those materials. this is still a wip and i ran out of time.


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From: Alain
Subject: Re: Testing ...
Date: 12 Apr 2017 19:39:46
Message: <58ee8282@news.povray.org>
Le 17-04-12 à 07:10, Jim Holsenback a écrit :
> On 4/12/2017 2:56 AM, Thomas de Groot wrote:
>> On 11-4-2017 14:28, Jim Holsenback wrote:
>>> ... these 3.7.1 features. All materials have the finish level fresnel.
>>> The key light uses the new light fading model. Used type 7 image map
>>> with the hdr probe surrounding everything and last but not least tau is
>>> used to position the camera and light source.
>>
>> Interesting, although I miss a bit of highlights on leaves and petals.
>> They seem a bit flat.
>>
> yeah i know what you mean ... it's the fresnel. perhaps a misuse for
> those materials. this is still a wip and i ran out of time.

What's the ior of your flower?
Remember that fresnel really always need an ior, or it just don't work 
at all.
My guess for the ior needed would be somewhere between 1.3 and 1.4. 
Close to that of water.


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From: Thomas de Groot
Subject: Re: Testing ...
Date: 13 Apr 2017 06:48:08
Message: <58ef1f28$1@news.povray.org>
On 12-4-2017 13:10, Jim Holsenback wrote:
> On 4/12/2017 2:56 AM, Thomas de Groot wrote:
>> On 11-4-2017 14:28, Jim Holsenback wrote:
>>> ... these 3.7.1 features. All materials have the finish level fresnel.
>>> The key light uses the new light fading model. Used type 7 image map
>>> with the hdr probe surrounding everything and last but not least tau is
>>> used to position the camera and light source.
>>
>> Interesting, although I miss a bit of highlights on leaves and petals.
>> They seem a bit flat.
>>
> yeah i know what you mean ... it's the fresnel. perhaps a misuse for
> those materials. this is still a wip and i ran out of time.

In any case, what I forgot to say, I believe such images would do very 
well in any future Insert Menu for the used features.

-- 
Thomas


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From: Jim Holsenback
Subject: Re: Testing ...
Date: 13 Apr 2017 11:40:28
Message: <58ef63ac$1@news.povray.org>
On 4/12/2017 3:40 PM, Alain wrote:
> Le 17-04-12 à 07:10, Jim Holsenback a écrit :
>> On 4/12/2017 2:56 AM, Thomas de Groot wrote:
>>> On 11-4-2017 14:28, Jim Holsenback wrote:
>>>> ... these 3.7.1 features. All materials have the finish level fresnel.
>>>> The key light uses the new light fading model. Used type 7 image map
>>>> with the hdr probe surrounding everything and last but not least tau is
>>>> used to position the camera and light source.
>>>
>>> Interesting, although I miss a bit of highlights on leaves and petals.
>>> They seem a bit flat.
>>>
>> yeah i know what you mean ... it's the fresnel. perhaps a misuse for
>> those materials. this is still a wip and i ran out of time.
> 
> What's the ior of your flower?
> Remember that fresnel really always need an ior, or it just don't work 
> at all.
> My guess for the ior needed would be somewhere between 1.3 and 1.4. 
> Close to that of water.

yep using 1.3 (water) and hollow on as well. fresnel is angle dependent 
(lighting and/or viewing) right? maybe that's where i'm missing the bus.

also (not /entirely/ unrelated) regarding variable reflection. it seems 
a bit threshold-ish ... that is: reflection { 0, 0.2 fresnel } doesn't 
give exactly what i'd expect but reflection { any-small-none-zero-value, 
0.2 fresnel } does


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From: clipka
Subject: Re: Testing ...
Date: 13 Apr 2017 17:18:40
Message: <58efb2f0$1@news.povray.org>
Am 13.04.2017 um 13:40 schrieb Jim Holsenback:

> also (not /entirely/ unrelated) regarding variable reflection. it seems
> a bit threshold-ish ... that is: reflection { 0, 0.2 fresnel } doesn't
> give exactly what i'd expect but reflection { any-small-none-zero-value,
> 0.2 fresnel } does

Sounds odd to me. Can you post an example?

Theoretically, a polished surface should work best with

    finish {
      diffuse albedo 1
      specular albedo 1 roughness VERY_SMALL
      fresnel
      reflection { 0, 1 fresnel }
      conserve_energy
    }

and it should be possible to shorten `reflection { 0, 1 fresnel }` to
`reflection { 1 fresnel }`.


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From: Jim Holsenback
Subject: Re: Testing ...
Date: 16 Apr 2017 13:32:55
Message: <58f37287@news.povray.org>
On 4/13/2017 1:18 PM, clipka wrote:
> Am 13.04.2017 um 13:40 schrieb Jim Holsenback:
> 
>> also (not /entirely/ unrelated) regarding variable reflection. it seems
>> a bit threshold-ish ... that is: reflection { 0, 0.2 fresnel } doesn't
>> give exactly what i'd expect but reflection { any-small-none-zero-value,
>> 0.2 fresnel } does
> 
> Sounds odd to me. Can you post an example?
> 
> Theoretically, a polished surface should work best with
> 
>      finish {
>        diffuse albedo 1
>        specular albedo 1 roughness VERY_SMALL
>        fresnel
>        reflection { 0, 1 fresnel }
>        conserve_energy
>      }
> 
> and it should be possible to shorten `reflection { 0, 1 fresnel }` to
> `reflection { 1 fresnel }`.
> 

i withdraw my threshold-ish comment after playing around with things a 
bit however i now have these observations:

in the attached image the object on the left has finish level fresnel 
/only/ and the object on the right the same but with fresnel off in the 
reflection block. all other finish attributes are identical for both 
objects. i was under the impression that specifying finish level fresnel 
/did not/ enable reflection level fresnel until specified!


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From: clipka
Subject: Re: Testing ...
Date: 17 Apr 2017 13:19:42
Message: <58f4c0ee$1@news.povray.org>
Am 16.04.2017 um 15:32 schrieb Jim Holsenback:

> in the attached image the object on the left has finish level fresnel
> /only/ and the object on the right the same but with fresnel off in the
> reflection block. all other finish attributes are identical for both
> objects. i was under the impression that specifying finish level fresnel
> /did not/ enable reflection level fresnel until specified!

I confess that this would have been my ad-hoc recollection, too -- but
looking at the source code and wiki I find that's neither how I
implemented it nor how it has been documented (quoting from
http://wiki.povray.org/content/Reference:Finish):

"Setting finish-level fresnel will automatically activate (if set to a
non-zero value) or deactivate (if set to zero) the reflection-level
fresnel parameter. This can be overridden by specifying the reflection
parameters after the finish-level fresnel parameter. [...]"

This is consistent with the implementation.


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