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From: Mike Horvath
Subject: Re: Blurred reflection comparison
Date: 17 Feb 2018 18:24:41
Message: <5a88b9b9$1@news.povray.org>
On 2/17/2018 4:01 PM, dick balaska wrote:
> On 02/17/2018 03:28 PM, Mike Horvath wrote:
>> I posted five images to Flickr showing my experiments with blurred 
>> reflections.
>>
>>
https://www.eurobricks.com/forum/index.php?/forums/topic/159291-pov-ray-surface-realism/

>>
>>
>> I asked on Eurobricks which is the most realistic image? I will also 
>> ask here. Which do you think look the most like real LEGO bricks?
>>
>>
>> Mike
> 
> I like #1 and #2. In all cases, the black road is way too reflective for 
> lego (although I like black reflective on principle).  Unless Lego has 
> changed a lot since I was a kid.
> 

All my bricks are so old and scarred I can't really come to a conclusion 
on my own. For instance, holding a brick so it reflects light from my 
lamp, I can make out the bulb pretty clearly as well as the lamp shade. 
But other nearby objects are barely visible. I don't know if brand new 
bricks would reflect more.


Mike


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From: And
Subject: Re: Blurred reflection comparison
Date: 18 Feb 2018 06:25:01
Message: <web.5a8962621a4227fab244fcf0@news.povray.org>
Mike Horvath <mik### [at] gmailcom> wrote:
> On 2/17/2018 4:01 PM, dick balaska wrote:
> > On 02/17/2018 03:28 PM, Mike Horvath wrote:
> >> I posted five images to Flickr showing my experiments with blurred
> >> reflections.
> >>
> >>
https://www.eurobricks.com/forum/index.php?/forums/topic/159291-pov-ray-surface-realism/
> >>
> >>
> >> I asked on Eurobricks which is the most realistic image? I will also
> >> ask here. Which do you think look the most like real LEGO bricks?
> >>
> >>
> >> Mike
> >
> > I like #1 and #2. In all cases, the black road is way too reflective for
> > lego (although I like black reflective on principle).  Unless Lego has
> > changed a lot since I was a kid.
> >
>
> All my bricks are so old and scarred I can't really come to a conclusion
> on my own. For instance, holding a brick so it reflects light from my
> lamp, I can make out the bulb pretty clearly as well as the lamp shade.
> But other nearby objects are barely visible. I don't know if brand new
> bricks would reflect more.
>
>
> Mike

Hi,

I have another observation for some blur reflection material, some surface is
more blur when you look it perpendicular. Just like variance reflection(aoi
pattern reflection amplitude), the blur has its aoi pattern.

But I don't know this is suitable for lego.


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From: clipka
Subject: Re: Blurred reflection comparison
Date: 18 Feb 2018 07:00:09
Message: <5a896ac9$1@news.povray.org>
Am 17.02.2018 um 21:28 schrieb Mike Horvath:
> I posted five images to Flickr showing my experiments with blurred
> reflections.
> 
>
https://www.eurobricks.com/forum/index.php?/forums/topic/159291-pov-ray-surface-realism/
> 
> 
> I asked on Eurobricks which is the most realistic image? I will also ask
> here. Which do you think look the most like real LEGO bricks?

I find it difficult to judge, as I'm not used to such large LEGO models.
I'd consider a closeup helpful.

Another tip you may or may not already be aware of: For best realism,
make sure to use a modern (v3.7.1/v3.8.0) version of POV-Ray, and make
use of the finish-level `fresnel` statement, e.g.:

    #declare MyLegoMaterial = material {
      interior { ior 1.6 }
      texture {
        pigment { ... }
        finish {
          ambient 0
          diffuse albedo DIFF
          specular albedo SPEC roughness ROUGH
          fresnel on
          reflection { SPEC fresnel on }
          conserve_energy on
        }
        normal { ... }
      }
    }

Presuming you're using normal-based blurred reflections, DIFF and SPEC
should probably be exactly 1.0 each(!), and ROUGH should be very low
(e.g. 0.0001).

Setting the finish-level `fresnel` parameter to `on` causes both the
diffuse component and specular highlights to vary with the viewing angle
in a realistic manner, making specular highlights more pronounced at
shallow angles (just like reflection-level `fresnel on` does for
specular reflection), while reducing the diffuse component's brightness
accordingly (just like `conserve_energy` does for transmitted light).


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From: Mike Horvath
Subject: Re: Blurred reflection comparison
Date: 18 Feb 2018 18:16:30
Message: <5a8a094e@news.povray.org>
On 2/18/2018 7:00 AM, clipka wrote:
> Am 17.02.2018 um 21:28 schrieb Mike Horvath:
>> I posted five images to Flickr showing my experiments with blurred
>> reflections.
>>
>>
https://www.eurobricks.com/forum/index.php?/forums/topic/159291-pov-ray-surface-realism/
>>
>>
>> I asked on Eurobricks which is the most realistic image? I will also ask
>> here. Which do you think look the most like real LEGO bricks?
> 
> I find it difficult to judge, as I'm not used to such large LEGO models.
> I'd consider a closeup helpful.
> 
> Another tip you may or may not already be aware of: For best realism,
> make sure to use a modern (v3.7.1/v3.8.0) version of POV-Ray, and make
> use of the finish-level `fresnel` statement, e.g.:
> 
>      #declare MyLegoMaterial = material {
>        interior { ior 1.6 }
>        texture {
>          pigment { ... }
>          finish {
>            ambient 0
>            diffuse albedo DIFF
>            specular albedo SPEC roughness ROUGH
>            fresnel on
>            reflection { SPEC fresnel on }
>            conserve_energy on
>          }
>          normal { ... }
>        }
>      }
> 
> Presuming you're using normal-based blurred reflections, DIFF and SPEC
> should probably be exactly 1.0 each(!), and ROUGH should be very low
> (e.g. 0.0001).
> 
> Setting the finish-level `fresnel` parameter to `on` causes both the
> diffuse component and specular highlights to vary with the viewing angle
> in a realistic manner, making specular highlights more pronounced at
> shallow angles (just like reflection-level `fresnel on` does for
> specular reflection), while reducing the diffuse component's brightness
> accordingly (just like `conserve_energy` does for transmitted light).
> 


Thanks for the tip. However, I changed the finish to this:



#local ldrawPlasticFin=finish {
  ambient			0
  diffuse albedo		1
  specular albedo	1
  roughness			0.0001
  fresnel			on
  reflection {1 fresnel on}
  conserve_energy
};



Now I see no reflections at all on the bricks.


Mike


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From: clipka
Subject: Re: Blurred reflection comparison
Date: 18 Feb 2018 20:03:29
Message: <5a8a2261$1@news.povray.org>
Am 19.02.2018 um 00:16 schrieb Mike Horvath:

> #local ldrawPlasticFin=finish {
>  ambient            0
>  diffuse albedo        1
>  specular albedo    1
>  roughness            0.0001
>  fresnel            on
>  reflection {1 fresnel on}
>  conserve_energy
> };
> 
> 
> 
> Now I see no reflections at all on the bricks.

Make sure that your materials have an `interior { ior FLOAT }` setting.
For LEGO materials, I recommend a value of 1.6.

When `fresnel` is set to `on`, the intensity of reflections not only
depends on the viewing angle, but also on the ratio between the
refractive index of the material and the refractive index of the medium
around (typically the "atmosphere", which has an ior of 1.0). The more
this ratio deviates from 1.0, the stronger the reflections will be.

By default, POV-Ray materials have an IOR of 1.0.


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From: Mike Horvath
Subject: Re: Blurred reflection comparison
Date: 18 Feb 2018 21:07:12
Message: <5a8a3150$1@news.povray.org>
On 2/18/2018 8:03 PM, clipka wrote:
> Make sure that your materials have an `interior { ior FLOAT }` setting.
> For LEGO materials, I recommend a value of 1.6.
> 
> When `fresnel` is set to `on`, the intensity of reflections not only
> depends on the viewing angle, but also on the ratio between the
> refractive index of the material and the refractive index of the medium
> around (typically the "atmosphere", which has an ior of 1.0). The more
> this ratio deviates from 1.0, the stronger the reflections will be.
> 
> By default, POV-Ray materials have an IOR of 1.0.
> 

Thanks, that worked. Would you be willing to take a look at each of the 
different LDraw materials? Currently, there are about 7 different ones, 
I think.


Mike


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From: clipka
Subject: Re: Blurred reflection comparison
Date: 18 Feb 2018 21:54:38
Message: <5a8a3c6e$1@news.povray.org>
Am 19.02.2018 um 03:07 schrieb Mike Horvath:
> On 2/18/2018 8:03 PM, clipka wrote:
>> Make sure that your materials have an `interior { ior FLOAT }` setting.
>> For LEGO materials, I recommend a value of 1.6.
>>
>> When `fresnel` is set to `on`, the intensity of reflections not only
>> depends on the viewing angle, but also on the ratio between the
>> refractive index of the material and the refractive index of the medium
>> around (typically the "atmosphere", which has an ior of 1.0). The more
>> this ratio deviates from 1.0, the stronger the reflections will be.
>>
>> By default, POV-Ray materials have an IOR of 1.0.
>>
> 
> Thanks, that worked. Would you be willing to take a look at each of the
> different LDraw materials? Currently, there are about 7 different ones,
> I think.

Dunno. Let me know what those materials are, and I'll try to give
recommendations.

I don't currently have the time to set up some LDraw->POV-Ray workflow
myself.


As mentioned before, LEGO's standard opaque plastic has a refractive
index of about 1.6, which also happens to be a good approximation for
LEGO's standard transparent plastic (both clear and tinted).


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From: Mike Horvath
Subject: Re: Blurred reflection comparison
Date: 19 Feb 2018 04:10:27
Message: <5a8a9483@news.povray.org>
On 2/18/2018 9:54 PM, clipka wrote:
> Am 19.02.2018 um 03:07 schrieb Mike Horvath:
>> Thanks, that worked. Would you be willing to take a look at each of the
>> different LDraw materials? Currently, there are about 7 different ones,
>> I think.
> 
> Dunno. Let me know what those materials are, and I'll try to give
> recommendations.
> 
> I don't currently have the time to set up some LDraw->POV-Ray workflow
> myself.
> 
> 
> As mentioned before, LEGO's standard opaque plastic has a refractive
> index of about 1.6, which also happens to be a good approximation for
> LEGO's standard transparent plastic (both clear and tinted).
> 

I attached the latest render as well as a copy of the material 
definitions I used to make the render. Currently, only the 
`ldrawPlasticABSFin` and `ldrawPlasticPolyFin` finishes are configured 
to your specifications. Good luck.


Mike


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Attachments:
Download 'wrapper_townview_close_06.jpg' (408 KB) Download 'materials_mjh_shadowno.inc.txt' (22 KB) Download 'blurred_reflection.inc.txt' (1 KB)

Preview of image 'wrapper_townview_close_06.jpg'
wrapper_townview_close_06.jpg

From: Mike Horvath
Subject: Re: Blurred reflection comparison
Date: 19 Feb 2018 04:23:17
Message: <5a8a9785@news.povray.org>
I forgot to make some important changes to the material definitions. 
I've attached the updated file.


Mike


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Attachments:
Download 'materials_mjh_shadowno.inc.txt' (22 KB)

From: Mike Horvath
Subject: Re: Blurred reflection comparison
Date: 24 Feb 2018 10:47:39
Message: <5a91891b$1@news.povray.org>
On 2/19/2018 4:23 AM, Mike Horvath wrote:
> I forgot to make some important changes to the material definitions. 
> I've attached the updated file.
> 
> 
> Mike

Christoph, do you have any tips on these materials? Thanks.


Mike


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