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24 Dec 2024 13:28:03 EST (-0500)
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From: Texel
Subject: materials
Date: 10 Jun 2003 13:10:03
Message: <3ee610eb@news.povray.org>
Hello,

I want to translate some material from Anim8or to PovRay (for a converter).

In anim8or, my materials have these properties:

Ambient: percentage, color, texture (it can be an image like .gif)
Diffuse:   percentage, color, texture (it can be an image like .gif)
Specular: percentage, color, texture (it can be an image like .gif)
Emissive: percentage, color, texture (it can be an image like .gif)
Transparancy: percentage, texture (it can be an image like .gif)
Bumpmap: percentage, texture (it can be an image like .gif)
Rough: percentage
Brillance: percentage


I am a beginner in Povray and i have tried to find some matches with Povray
materials, but i have not found all of these properties.

How can i modify this example of material in order to convert all of the
propertises i have listed above?
(for example i don't know how to put a diffuse color to this material,
without removing the image).

#declare material01 = texture {
uv_mapping pigment {
   image_map {
   gif "pierres.gif"
   map_type 0
   interpolate 0
   }
}
finish { ambient rgb <0.0,0.0,1.0>}
finish { diffuse 0.7}

}

Thanks.


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From: Christopher James Huff
Subject: Re: materials
Date: 10 Jun 2003 13:44:13
Message: <cjameshuff-FE7902.12354510062003@netplex.aussie.org>
In article <3ee610eb@news.povray.org>,
 "Texel" <gsm### [at] netcourriercom> wrote:

> In anim8or, my materials have these properties:
> 
> Ambient: percentage, color, texture (it can be an image like .gif)
> Diffuse:   percentage, color, texture (it can be an image like .gif)
> Specular: percentage, color, texture (it can be an image like .gif)
> Emissive: percentage, color, texture (it can be an image like .gif)
> Transparancy: percentage, texture (it can be an image like .gif)
> Bumpmap: percentage, texture (it can be an image like .gif)
> Rough: percentage
> Brillance: percentage
> 
> 
> I am a beginner in Povray and i have tried to find some matches with Povray
> materials, but i have not found all of these properties.
> 
> How can i modify this example of material in order to convert all of the
> propertises i have listed above?
> (for example i don't know how to put a diffuse color to this material,
> without removing the image).

Most of these are finish attributes. Here's what is available:

ambient float | color
diffuse float
specular float
roughness float
brilliance float

The "roughness" keyword controls specular, it may not be equivalent to 
whatever anim8or "rough" is. I don't know what "emissive" could be. 
Transparency is usually defined as part of the color, specifying it as 
part of an image_map is a bit trickier, and it can not be defined by an 
image. There is a bump_map feature which is part of the normal 
statement. POV is a bit more limited in that many things are only 
specified as floats or constant colors. The finish diffuse item is just 
a scaling factor for the pigment color. The syntax is fully described in 
the manual.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/


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From: Patrick Elliott
Subject: Re: materials
Date: 10 Jun 2003 14:48:17
Message: <MPG.194fd57b4b699e2a98981f@news.povray.org>
In article <3ee610eb@news.povray.org>, gsm### [at] netcourriercom says...
> Hello,
> 
> I want to translate some material from Anim8or to PovRay (for a converter).
> 
> In anim8or, my materials have these properties:
> 
> Ambient: percentage, color, texture (it can be an image like .gif)
> Diffuse:   percentage, color, texture (it can be an image like .gif)
> Specular: percentage, color, texture (it can be an image like .gif)
> Emissive: percentage, color, texture (it can be an image like .gif)
> Transparancy: percentage, texture (it can be an image like .gif)
> Bumpmap: percentage, texture (it can be an image like .gif)
> Rough: percentage
> Brillance: percentage
> 
> 
> I am a beginner in Povray and i have tried to find some matches with Povray
> materials, but i have not found all of these properties.
> 
> How can i modify this example of material in order to convert all of the
> propertises i have listed above?
> (for example i don't know how to put a diffuse color to this material,
> without removing the image).
> 
> #declare material01 = texture {
> uv_mapping pigment {
>    image_map {
>    gif "pierres.gif"
>    map_type 0
>    interpolate 0
>    }
> }
> finish { ambient rgb <0.0,0.0,1.0>}
> finish { diffuse 0.7}
> 
> }
> 

Hmm.. Simplest answer would probably be that you can't directly. Ambient, 
Diffuse and Specular are coupled to the image map or color you use in 
POV-Ray. They can't be specified as different colors. Emissive doesn't 
really exist, there are way to make a light that has a specific shape, 
but you can't make a normal object 'emit' at a different color than its 
own. The exception to this rule would be a partly transparent object 
containing media that emits in the color you want. Also, when using 
radiosity, the ambient will function as emitting I believe.

Some of this might be possible to do with layered textures, like a green 
object with a partly transparent red layer that has an ambient property. 
That 'should' make the red more obvious in shadow while the green would 
fade out. You could do some similar things with diffuse and specular, but 
again, the layers need to be at least partly transparent for them to 
blend together.

Transparency is generally a function of the image map, texture or color 
used, though there may be a way to make it like Anim8or. I know you could 
do so by taking the existing single color and adding <0,0,0,1> to it. You 
would need to do that for every color used, however I am not sure how you 
tweak an image in that fashion.

Bumpmap and brilliance may or may not work the same.

Rough would be roughness and only works with specular hilights.

This is my best guess, from nosing through the documentation. Someone 
else may be able to provide a better idea about more complex stuff. Seems 
Anim8or provides some quirky ways to set up some of this stuff, but then 
this is not surprising, since the point of POV-Ray is realism, so it is 
designed to calculate most of these things based on the real object 
properties, not discreet definitions, while Anim8or uses these quirky 
things to avoid having to make such calculations in most cases. In those 
cases where Anim8or textures use the same 0-1 values it appears that the 
result would be near direct translation, but when you start using a 
different color or pattern for each property... ;)

-- 
void main () {

    call functional_code()
  else
    call crash_windows();
}


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From: Texel
Subject: Re: materials
Date: 10 Jun 2003 15:10:44
Message: <3ee62d34@news.povray.org>
Ok. Thanks.

Actually, i have to decide if i want to use image OR color (except for
ambient) ?

"emissive" is a color that is emitted by an object (like a light bulb).
If it's not clear enough, you can find some informations here:
http://fly.srk.fer.hr/%7eunreal/theredbook/chapter06.html

For transparency, do i have to use (or can i use) a image with alpha values
(such as .tga) ? It's very boring.  I would have to use "The Gimp" each
times i want to change to transparency value of my images?!


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From: Texel
Subject: Re: materials
Date: 10 Jun 2003 15:29:29
Message: <3ee63199@news.povray.org>
>Seems Anim8or provides some quirky ways to set up some of this stuff, but
then
> this is not surprising, since the point of POV-Ray is realism, so it is
> designed to calculate most of these things based on the real object
> properties, not discreet definitions, while Anim8or uses these quirky
> things to avoid having to make such calculations in most cases.

Anim8or set up the materials in the same way 3DS Max does (an like a lots of
other modelling programs i think). And 3DS Max can create some very
realistic picture like PovRay :)

I will try some other converters or scripts (from other modellling programs)
in order to see how they convert materials.


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From: Tom Melly
Subject: Re: materials
Date: 11 Jun 2003 09:14:32
Message: <3ee72b38$1@news.povray.org>
"Texel" <gsm### [at] netcourriercom> wrote in message
news:3ee610eb@news.povray.org...

<snip>

Just as a suggestion, I would try modelling some very simple textures in
anim8tor, using just one attribute at a time, and then try and duplicate the
texture in POV.

Some postings of the anim8tor settings and resultant images might help povers to
work out what the anim8tor settings equate to in pov.


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From: Anto Matkovic
Subject: Re: materials
Date: 11 Jun 2003 11:12:16
Message: <3ee746d0@news.povray.org>
> Hello,
>
> I want to translate some material from Anim8or to PovRay (for a
converter).
>
> In anim8or, my materials have these properties:
>
> Ambient: percentage, color, texture (it can be an image like .gif)
> Diffuse:   percentage, color, texture (it can be an image like .gif)
> Specular: percentage, color, texture (it can be an image like .gif)
> Emissive: percentage, color, texture (it can be an image like .gif)
> Transparancy: percentage, texture (it can be an image like .gif)
> Bumpmap: percentage, texture (it can be an image like .gif)
> Rough: percentage
> Brillance: percentage
>
>
- POV-Ray have a default global ambient set to 1 (rgb 255), in dinstinction
to many scanlines, where this is usually zero or dark grey. If you find on
IRTC site some images with a dark, well saturated colors like an old
painting, this can be work of Jaime Vives Piqueres. He was used a global
ambient color
set to zero.
- POV values can go over 1 or lower to zero (something like rgb 788 or
rgb -200; not too much usable, but you may know that)
- POV ambient color (in materials) working  something like the ambient and
emission (self illumination) together - ambient 1 (both global and 'local')
and diffuse 0 will do 'flat' , intact, pigment colors.
- diffuse is a simple value, not a color or image
- pigment is something like diffuse color, also transparency can be inside
(in POV: filter or transmit)
- transparency or filter color depend on pigment color
- bumpmap is near the same
- POV specular and roughness come with POV specular highlight - it can be
also phong,  or both of them on the same material.
- Brilliance is a something similar (I suppose)
- POV materials haven't independent  highlights color, this depend on the
light color. In case of metallic finish, this do not depend (more precisely,
'near to do not depend').
- POV-Ray distribution sample scenes, and code from 'insert menu' can have a
different 'assumed gamma' value - you need to pay attention to that.

As a pretty old POV home user, and Max user at work, I can say, that's hard
to say what is more realistic, or 'better'. POV materials controls are
surely simplier and easier to figure out, 'more logic', usually they are
easier for tweaking, and don't tend to loose saturation like a many
scanlines (better color clamping, I suppose). Also,
antialiasing-oversampling things are much easier to setup in raytracers than
in scanlines. Even some good scanline renderers tricks (bitmap environment
reflection, as example) are near to impossible in POV.
Roughly, POV is a typicaly raytracer (what a surprise:), and a very fast
raytracer.


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From: Christopher James Huff
Subject: Re: materials
Date: 11 Jun 2003 16:54:54
Message: <cjameshuff-0240D3.15463011062003@netplex.aussie.org>
In article <3ee746d0@news.povray.org>,
 "Anto Matkovic" <ant### [at] matkoviccom> wrote:

> - POV-Ray have a default global ambient set to 1 (rgb 255), in dinstinction
> to many scanlines, where this is usually zero or dark grey. If you find on
> IRTC site some images with a dark, well saturated colors like an old
> painting, this can be work of Jaime Vives Piqueres. He was used a global
> ambient color set to zero.

This value is actually a multiplier for the finish ambient values. If 
set to 0, it is the same as setting all ambient values in the scene to 
0. 0.5 is equivalent to halving them. Or you could use a color to give 
the scene a specific color cast. It really doesn't do anything you can't 
do otherwise, and setting it to 0 makes it impossible to create glowing 
objects with radiosity. A better solution is to adjust the default 
texture values:
#default {finish {ambient 0 diffuse 1}}

This way, objects have no ambient light unless you specify it, and the 
pigment alone specifies the diffuse reflection. However, if you find out 
you *do* need ambient, for a glowing light bulb for example, you can 
still use it. You can also set the other texture items this way...for 
example, you could set the default pigment to be a seizure inducing 
candy-striped neon green and hot pink, which will quickly alert you if 
you forget to specify a pigment.


> - POV values can go over 1 or lower to zero (something like rgb 788 or
> rgb -200; not too much usable, but you may know that)

Values greater than 1 are useful, especially with more accurate light 
simulation features such as radiosity. Real-world scenes have great 
variation in lighting, not a limited range.


> - POV materials haven't independent  highlights color, this depend on the
> light color. In case of metallic finish, this do not depend (more precisely,
> 'near to do not depend').

With metallic highlights, the surface color affects the highlight color. 
The light color is still important though.

-- 
Christopher James Huff <cja### [at] earthlinknet>
http://home.earthlink.net/~cjameshuff/
POV-Ray TAG: chr### [at] tagpovrayorg
http://tag.povray.org/


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From: Anto Matkovic
Subject: Re: materials
Date: 11 Jun 2003 19:22:25
Message: <3ee7b9b1@news.povray.org>
Christopher,
thanks for explanations (my English is 'as is') - also I don't use POV too
much in a last few years.
I hope I will have a chance to see some of your images.

best regards,
Anto
http://www.matkovic.com/anto

> > - POV-Ray have a default global ambient set to 1 (rgb 255), in
dinstinction
> > to many scanlines, where this is usually zero or dark grey. If you find
on
> > IRTC site some images with a dark, well saturated colors like an old
> > painting, this can be work of Jaime Vives Piqueres. He was used a global
> > ambient color set to zero.
>
> This value is actually a multiplier for the finish ambient values. If
> set to 0, it is the same as setting all ambient values in the scene to
> 0. 0.5 is equivalent to halving them. Or you could use a color to give
> the scene a specific color cast. It really doesn't do anything you can't
> do otherwise, and setting it to 0 makes it impossible to create glowing
> objects with radiosity. A better solution is to adjust the default
> texture values:
> #default {finish {ambient 0 diffuse 1}}
>
> This way, objects have no ambient light unless you specify it, and the
> pigment alone specifies the diffuse reflection. However, if you find out
> you *do* need ambient, for a glowing light bulb for example, you can
> still use it. You can also set the other texture items this way...for
> example, you could set the default pigment to be a seizure inducing
> candy-striped neon green and hot pink, which will quickly alert you if
> you forget to specify a pigment.
>
>
> > - POV values can go over 1 or lower to zero (something like rgb 788 or
> > rgb -200; not too much usable, but you may know that)
>
> Values greater than 1 are useful, especially with more accurate light
> simulation features such as radiosity. Real-world scenes have great
> variation in lighting, not a limited range.
>
>
> > - POV materials haven't independent  highlights color, this depend on
the
> > light color. In case of metallic finish, this do not depend (more
precisely,
> > 'near to do not depend').
>
> With metallic highlights, the surface color affects the highlight color.
> The light color is still important though.
>
> --
> Christopher James Huff <cja### [at] earthlinknet>
> http://home.earthlink.net/~cjameshuff/
> POV-Ray TAG: chr### [at] tagpovrayorg
> http://tag.povray.org/


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