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wizlon
02-22-2006, 08:58 AM
Do DGS and opaque materials in general exhibit the fresnel effect?

Mental ray's DGS material does'nt seem to include this. Is this a fake and is Fresnel only relevent in transparent materials like glass?

Confused.

Cheers.

Lee.

wizlon
02-23-2006, 09:24 AM
bump.

I really would like to solve this, any help or thoughts would be much appreciated.

Is the DGS just a base for you to add other atributes i.e. fresnel effect, because Mental images state that DGS is a physically acurate material but without taking into account the Fresnel effect how can this be true?

Ta
.


Lee.

T-R
02-23-2006, 01:29 PM
Brendan McCaffrey has put togeather some great phenomenon one of which includes a dgs Fresnel. His collection is a must have IMO.


http://www.bmcaff.com/

wizlon
02-23-2006, 01:37 PM
Yes, thanks I have these, but is this a fake? do Opaque material really exhibit the Fresnel effect?

or did Brendan create these purely for athesetic reasons?

T-R
02-23-2006, 02:28 PM
Oh I see sorry.

"Nearly every material shows this effect more or less, especially transparent objects (every material is "transparent" btw. - it just depends on how many atoms the light can shine through)."


source:

http://www.the123d.com/tutorial/general3/reflections01.shtml

LehaS
02-23-2006, 10:35 PM
built-in dielectric shader supports freshnel effect and mib_glossy shaders also....as it was already mentioned there are also custom shaders developed which exhibit freshnel effect...

Make a search on freshnel and you ll find lots of info on this boards....MR shaders manual i a good place for research also...

wizlon
02-24-2006, 09:32 AM
Thanks Leha, but like I asked in my original question I really needed to know;

Do opaque materials like plastic for example, exhibit the fresnel effect?

Is Fresnel only relevent in transparent/refractive materials like glass, water?

here's a post from another thread:

'The Fresnel effect is based on refraction. You don't get it on opaque objects unless you're dealing with coatings as in car paints.' Chris_TC.

Thanks all.

floze
02-24-2006, 01:10 PM
Thanks Leha, but like I asked in my original question I really needed to know;

Do opaque materials like plastic for example, exhibit the fresnel effect?

Is Fresnel only relevent in transparent/refractive materials like glass, water?

here's a post from another thread:

'The Fresnel effect is based on refraction. You don't get it on opaque objects unless you're dealing with coatings as in car paints.' Chris_TC.

Thanks all.
http://www.graphics.cornell.edu/~westin/misc/fresnel.html
http://www.google.com/search?hl=en&lr=&q=fresnel+reflectance&btnG=Search

And bob's your uncle.

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