This is a question of general interest I think.

I have a couple of objects (coming originally from Daz3D) of which the 
materials' specular sizes are translated to 100 in Poseray, and from there 
to roughness values of 0.2xxx in POV-Ray, even after I have modified the 
materials, both in Poser and in Silo. The high roughness makes the materials 
look washed out.

I have been looking into the parameters in all the applications, but I 
cannot discover what exactly triggers this anomalously high setting.

Any idea?

Thomas

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Thomas,

There is a specular size that controls the roughness value in the 
materials tab of PoseRay. PoseRay uses specular+roughness for 
highlights. In Poser this is controlled by the highlight size and in 
DAZ|Studio it is the glossiness in the advanced tab for each surface.

DAZ|Studio has a bug that results in exported scenes with full specular 
strength. Specular strength in DAZ|Studio is a multiplier of the 
highlight color. The only reason I see this parameter exists is for 
changing the amount of highlight without changing the RGB ratio of the 
highlight. Rather useless.

later,

FlyerX



Thomas de Groot wrote:
> This is a question of general interest I think.
> 
> I have a couple of objects (coming originally from Daz3D) of which the 
> materials' specular sizes are translated to 100 in Poseray, and from there 
> to roughness values of 0.2xxx in POV-Ray, even after I have modified the 
> materials, both in Poser and in Silo. The high roughness makes the materials 
> look washed out.
> 
> I have been looking into the parameters in all the applications, but I 
> cannot discover what exactly triggers this anomalously high setting.
> 
> Any idea?
> 
> Thomas
> 
>

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Thank you indeed FlyerX!
This fully answers my question and the DS bug explains the puzzle I hit 
upon.

Thomas


"FlyerX" <fly### [at] yahoocom> schreef in bericht 
news:469e58a7$1@news.povray.org...
> Thomas,
>
> There is a specular size that controls the roughness value in the 
> materials tab of PoseRay. PoseRay uses specular+roughness for highlights. 
> In Poser this is controlled by the highlight size and in DAZ|Studio it is 
> the glossiness in the advanced tab for each surface.
>
> DAZ|Studio has a bug that results in exported scenes with full specular 
> strength. Specular strength in DAZ|Studio is a multiplier of the highlight 
> color. The only reason I see this parameter exists is for changing the 
> amount of highlight without changing the RGB ratio of the highlight. 
> Rather useless.
>
> later,
>
> FlyerX
>
>
>
> Thomas de Groot wrote:
>> This is a question of general interest I think.
>>
>> I have a couple of objects (coming originally from Daz3D) of which the 
>> materials' specular sizes are translated to 100 in Poseray, and from 
>> there to roughness values of 0.2xxx in POV-Ray, even after I have 
>> modified the materials, both in Poser and in Silo. The high roughness 
>> makes the materials look washed out.
>>
>> I have been looking into the parameters in all the applications, but I 
>> cannot discover what exactly triggers this anomalously high setting.
>>
>> Any idea?
>>
>> Thomas
>>

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I did a little test with Silo too.

Silo has a material parameter called 'shininess', which controls the size of 
the specular highlights. By default, it is at value 127. This translates in 
Poseray to Specular Size 1, and hence to POV-Ray to a roughness of 
approximately 0.002

In the same way:
a shininess value of 10 in Silo, translates to Specular Size 10 and 
roughness 0.02443085
a shininess value of 20 in Silo, translates to Specular Size 5 and roughness 
0.01244878
a shininess value of 30 in Silo, translates to Specular Size 3 and roughness 
0.007655948
a shininess value of 40 in Silo, translates to Specular Size 3 and roughness 
0.007655948
a shininess value of 50 in Silo, translates to Specular Size 2 and roughness 
0.005259534
a shininess value of 60 in Silo, translates to Specular Size 2 and roughness 
0.005259534

I assume (but I may be wrong) that shininess plays a fairly identical role 
to 'glossiness' in DS. However, it works consistently as is shown by the 
test.

Thomas

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Thomas,

This shows one of the main drawbacks of all 3D applications. Although 
geometry made up of polygons transfers perfectly most of the time. There 
is no consistent way of defining materials. Even if the material 
properties are named the same and use the same format they are usually 
interpreted differently.

Some times this occurs because of of closed format specifications and 
other times because developers do not adhere to the published 
specifications for the format used. Maybe some time in the future there 
will be a unified format like PDF is for print work today. This does not 
even cover other topics like animation, lighting and commercialization 
which complicates the creation of an unified 3D format more difficult.

In fact the current PDF standard now includes full 3D objects now so 
maybe there is a chance of this happening.

FlyerX

Thomas de Groot wrote:
> I did a little test with Silo too.
> 
> Silo has a material parameter called 'shininess', which controls the size of 
> the specular highlights. By default, it is at value 127. This translates in 
> Poseray to Specular Size 1, and hence to POV-Ray to a roughness of 
> approximately 0.002
> 
> In the same way:
> a shininess value of 10 in Silo, translates to Specular Size 10 and 
> roughness 0.02443085
> a shininess value of 20 in Silo, translates to Specular Size 5 and roughness 
> 0.01244878
> a shininess value of 30 in Silo, translates to Specular Size 3 and roughness 
> 0.007655948
> a shininess value of 40 in Silo, translates to Specular Size 3 and roughness 
> 0.007655948
> a shininess value of 50 in Silo, translates to Specular Size 2 and roughness 
> 0.005259534
> a shininess value of 60 in Silo, translates to Specular Size 2 and roughness 
> 0.005259534
> 
> I assume (but I may be wrong) that shininess plays a fairly identical role 
> to 'glossiness' in DS. However, it works consistently as is shown by the 
> test.
> 
> Thomas
> 
>

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Yes, absolutely, FlyerX.
I found this little test very revealing and it learned me a lot. This Babel 
cacophony in 3D applications made me also accutely aware of the tremendous 
achievements you have reached with Poseray. I can hardly imagine what 
exchanges would have been between Poser, Silo, Wings3D, and POV-Ray 
(forgetting all other applications) without Poseray. The habit of using it 
is so deeply rooted now that we hardly pay attention and think that this is 
business as usual.

Thomas

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My suggestion is to build your own material library directly for Povray and
save it as a text file. Then when you import the scene, you do have to do
some copying and pasting and maybe some other text editing if you use an
image map, but you know what you're getting.

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"fls13" <fls### [at] netzeronet> schreef in bericht 
news:web.46aa9d5e3c289d0946bda8110@news.povray.org...
> My suggestion is to build your own material library directly for Povray 
> and
> save it as a text file. Then when you import the scene, you do have to do
> some copying and pasting and maybe some other text editing if you use an
> image map, but you know what you're getting.
>

Oh yes, of course, I do that quite a lot as a matter of fact. My point 
really was that I got intrigued by the way different applications simulate, 
e.g. specular, and how that translates to POV-Ray. Initially, in my naive 
thinking, I thought that the approach would be the same from all 
applications, but of course that just isn't true. interesting experiments, 
though...

Thomas

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