Stephen <mcavoys_at@aoldotcom> wrote:
> I already extracted those figures into Excel so I could play with them
> but you seemed to have missed out the Relative index of refraction. 1.3
> for most of the materials and 1.5 for Marble (I assume that it is
> important). I also found it useful to be able to change the specular and
> roughness in my material.

Well, the refraction would be at the material/object level, as part of the
interior. Water is IOR ~1.3, glass, jade, and pearl are ~1.5, and diamond is
~2.4, not sure what ivory would be.

Anyway, these are just textures that I defined as base SSLT-only textures.
I've noticed that the current SSLT implementation doesn't play well with complex
pigments like color_maps or image_maps; it just seems to ignore them. So I've
been experimenting with layered and patterned textures instead of just pure
SSLT, getting results like these (with spec, roughness, etc in non-SSLT
layers/patterns).

-------------------------------------------------
www.McGregorFineArt.com

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Attachments:
Download 'sslt_textures19.png' (310 KB)

Preview of image 'sslt_textures19.png'

"Robert McGregor" <rob### [at] mcgregorfineartcom> wrote:
> not sure what ivory would be.

Okay, I just found this extensive IOR listing with ivory at IOR 1.54:

http://interactagram.com/physics/optics/refraction/

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>
> Well, the refraction would be at the material/object level, as part of the
> interior. Water is IOR ~1.3, glass, jade, and pearl are ~1.5, and diamond is
> ~2.4, not sure what ivory would be.

> Okay, I just found this extensive IOR listing with ivory at IOR 1.54:

http://interactagram.com/physics/optics/refraction/

Excellent! Just bookmarked it, thanks.

> Anyway, these are just textures that I defined as base SSLT-only textures.

That's a problem with using a modeller, I don't know these coding 
tricks. :-( I thought...

> I've noticed that the current SSLT implementation doesn't play well with complex
> pigments like color_maps or image_maps; it just seems to ignore them. So I've
> been experimenting with layered and patterned textures instead of just pure
> SSLT, getting results like these (with spec, roughness, etc in non-SSLT
> layers/patterns).
>

The Ketchup would make a good marble but I would not like to drink the 
wholemilk. ;-)

The settings I used for my ivory were:
IOR 1.5
colour rgbft <0.914,0.906,0.620,0.000,0.000>
ambient     rgb <0.100,0.100,0.0945>
subsurface { <3,3,2> * 
<0.914,0.906,0.620>,<0.914,0.906,0.620>*<0.914,0.906,0.620>/1000 }



-- 
Regards
     Stephen

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Am 12.02.2011 21:11, schrieb Stephen:

> but you seemed to have missed out the Relative index of refraction. 1.3
> for most of the materials and 1.5 for Marble (I assume that it is
> important).

Yup, 'tis.

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> lamp. The figure is supposed to be made of ivory.
> I know that the values for subsurface { <R,G,B>, <R,G,B>} should be

> Light Transport does not give any values for ivory. Does anyone have any
> ideas how to fudge them?
>
> Comments and ideas welcome.
>

You may try the values for some bone or bone like materials. Ivory is 
after all a kind of bone.

As it is now, the figurine lamp looks more like brass.


Alain

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On 13/02/2011 3:22 AM, Alain wrote:
>
> You may try the values for some bone or bone like materials. Ivory is
> after all a kind of bone.
>

Unfortunately the paper does not have any values for bone-like materials.

> As it is now, the figurine lamp looks more like brass.

I was going for an old ivory look so I expected it to be yellowish. But 
you are right, I thought that the brassy look was from the green light 
from the window. In isolation the hair and arms are still brassy.
Back to the drawing board.


-- 
Regards
     Stephen

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On 02/12/2011 04:49 PM, Stephen wrote:
>> On 12/02/2011 8:21 PM, Jim Holsenback wrote:
>> btw: had a lamp
>> fairly close to what you've got in the shop several years ago except her
>> arms were more upwards and the lamp globe was opalescent
> 

> very fashionable and out of my price range. :-(

yes some of them CAN be pricey ... especially now that some are getting
to be close to 100 years old (10/20 more years). conservative start at
$500/750 ... quadruple or more if it's a famous artist/maker like
tiffany (usually signed) once saw a pair of lamps (one table and one
standing) ... tiffany lily go at an auction for just under $10K

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Am 13.02.2011 04:22, schrieb Alain:

> You may try the values for some bone or bone like materials. Ivory is
> after all a kind of bone.

Not really. Unless you call teeth a kind of bone, too.

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> Am 13.02.2011 04:22, schrieb Alain:
>
>> You may try the values for some bone or bone like materials. Ivory is
>> after all a kind of bone.
>
> Not really. Unless you call teeth a kind of bone, too.

In fact, teeth and bone are essentialy the same base material: calcium 
carmonates.
The enamel covering a teeth is much harder and tranparent, but the 
dentine under that is relatively close to bone and tend toward yellow-beige.

Usualy, ivory tend to be somewhat yellower than bone, even beige, 
especialy after several years.
Ivory can get a beter polish due to a generaly higher density.



Alain

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On 13/02/2011 4:14 PM, Jim Holsenback wrote:

>> very fashionable and out of my price range. :-(
>
> yes some of them CAN be pricey ... especially now that some are getting
> to be close to 100 years old (10/20 more years). conservative start at
> $500/750 ... quadruple or more if it's a famous artist/maker like
> tiffany (usually signed) once saw a pair of lamps (one table and one
> standing) ... tiffany lily go at an auction for just under $10K
>

No wonder I only looked. I do have a couple of chromed barley sugar 
twist lamps (Art Deco). I've never seen opalescent shades only frosted 
white ones.
BTW do you have any code for "opalescent"?

-- 
Regards
     Stephen

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