[Req] Specular / IOR mapping of texture

mrCarnivore · Post by **mrCarnivore** » Tue Mar 13, 2007 12:09 am

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.

Post by **OnoSendai** » Tue Mar 13, 2007 12:12 am

Well.. you can blend with a diffuse material, or with another specular material with lower fresnel_fraction if you want

SmartDen · Post by **SmartDen** » Tue Mar 13, 2007 12:27 am

Can you give an example, Ono? Or anybody else?

mrCarnivore · Post by **mrCarnivore** » Tue Mar 13, 2007 12:52 am

@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...

suvakas · Post by **suvakas** » Tue Mar 13, 2007 1:01 am

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

mrCarnivore · Post by **mrCarnivore** » Tue Mar 13, 2007 1:30 am

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?

Post by **OnoSendai** » Tue Mar 13, 2007 1:33 am

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.

suvakas · Post by **suvakas** » Tue Mar 13, 2007 1:48 am

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:

Post by **OnoSendai** » Tue Mar 13, 2007 1:57 am

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

)

suvakas · Post by **suvakas** » Tue Mar 13, 2007 2:01 am

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

Kram1032 · Post by **Kram1032** » Tue Mar 13, 2007 2:30 am

lol funny result!

mrCarnivore · Post by **mrCarnivore** » Tue Mar 13, 2007 3:11 am

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?

CTZn · Post by **CTZn** » Tue Mar 13, 2007 4:14 am

The exponent of phong can be mapped already isnt'it ?

[Req] Specular / IOR mapping of texture

[Req] Specular / IOR mapping of texture

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