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[Req] Specular / IOR mapping of texture
Posted: Tue Mar 13, 2007 12:09 am
by mrCarnivore
Another very important aspect for a photorealistic renderer is imho the ability to pply a texture as a specular map. Meaning, that the specularity of a glossy surface can vary according to a (bw-)texture.
This is extremely important if you want to render realistic skin or dirty glossy materials.
Posted: Tue Mar 13, 2007 12:12 am
by OnoSendai
Well.. you can blend with a diffuse material, or with another specular material with lower fresnel_fraction if you want

Posted: Tue Mar 13, 2007 12:27 am
by SmartDen
Can you give an example, Ono? Or anybody else?
Posted: Tue Mar 13, 2007 12:52 am
by mrCarnivore
@OnoSendai: Mmh. Haven't thought about that. Guess I have to admit it is possible.
But as with alpha-mapping this technique is hardly user-friendly. And as far as I understand it, you can only use it as a blend between TWO material settings and not a gradual change in paramtesrs according to the grey-level of the texture pixel...
@SmartDen: OnoSendai is referring to the technique described here:
http://www2.indigorenderer.com/joomla/f ... php?t=1225
Although in this case it is decribed for alpha-mapping, it can also be used for specular-mapping or any other change of material-paramters according to a texture...
Posted: Tue Mar 13, 2007 1:01 am
by suvakas
You can blend as many blend-materials as you want
What do you mean its not working with gradual greys? The blend mask can have whatever gradient in it
Suvakas
Posted: Tue Mar 13, 2007 1:30 am
by mrCarnivore
suvakas wrote:You can blend as many blend-materials as you want
Ok, I will put that remark in the theoretically-possible-but-really-not-usable corner...
But hey, if you write a nice exporter that handles all the awkwardness and delivers a nive user-interface and this blend-blending does not slow down indigo even more, be my guest.
suvakas wrote:What do you mean its not working with gradual greys? The blend mask can have whatever gradient in it
Suvakas
Is that so? What you are telling me is that if I have a material with exponent 50 and a material with exponent 1000 I can gradually blend those two materials using a texture that consists of shades of grey?
Posted: Tue Mar 13, 2007 1:33 am
by OnoSendai
mrCarnivore wrote:
Is that so? What you are telling me is that if I have a material with exponent 50 and a material with exponent 1000 I can gradually blend those two materials using a texture that consists of shades of grey?
Yes.. that should work fine.

Posted: Tue Mar 13, 2007 1:48 am
by suvakas
Hey Ono, I just did a test with blend materials and I can't blend between 2 separate blend materials that are using null material (confusing?

)
Suvakas
Here is an example:
Posted: Tue Mar 13, 2007 1:57 am
by OnoSendai
Yeah, that doesn't work Suvakas.
I don't know if you will ever be able to blend multiple transparent materials together. (have to think about it some more

)
Posted: Tue Mar 13, 2007 2:01 am
by suvakas
Gotcha ! Ok. Actually it would be no problem for me cause i never use a combo like this. Just fooled around for testing purposes
Suvakas
Posted: Tue Mar 13, 2007 2:30 am
by Kram1032
lol funny result!
Posted: Tue Mar 13, 2007 3:11 am
by mrCarnivore
Which brings me back to my original request...
So you just want to leave this current realisation or are you thinking about implementing a more user-friendly approach?
Posted: Tue Mar 13, 2007 4:14 am
by CTZn
The exponent of phong can be mapped already isnt'it ?