what's the differnece in fresnel and...

[lukx]

Can someone please explain me what is the difference when using for glass checked fresnel on and in reflection map fallof with fresnel fallof.
I mean which should be used for glass materials and which for standard mat with some reflection on? How I understand this for realistic glass I should use fresnel on and that is it. But for other materials like plastic or enything else I should put fallof into reflection map with fallof type set to fresnel. Do I get it right?. But the thing is that very offen when I'm using fresnel on glass I got almoust no reflections even when using hdri spherical maps for reflection.

[jujubee]

For fresnel glass reflections are you turning up your IOR to about values of 5-10?

[DaForce]

You should get reflections as long as the reflection color is full white and fresnel is ticked. But it all depends on the shape and position of your glass.
The fresnel tick box is basically fine for everything, but putting a falloff map set to fresnel just allows you some more control

[lukx]

For fresnel glass reflections are you turning up your IOR to about values of 5-10?

5-10 ?! I thought for glass it's 1.54 or something.

"You should get reflections as long as the reflection color is full white "
but in real glass for example widnows, reflections aren't always 100% right?

[DaForce]

The "refraction" IOR of glass is around 1.54.
The reflection depends on the glass surface.

Put reflection color to full white and then turn on fresnel, it wont be 100% thats what fresnel does. You can also untick the little L and then you can control the IOR of the reflection (being more or less reflective) and thus leaving the refraction at 1.54 (where it should be)

Also you will get reflection sif your reflection color isnt pure white but they wont be as strong.... just try it and see but you must tick fresnel

[lukx]

Thank you DaForce now I got it.

[DaForce]

Excellent

[lukx]

Just one more question. Are there any tables with values for reflection IOR like there are for refraction?

[DaForce]

well not that im aware of. Because it all depends on alot of things.. like what type of glass, if its clean or not, if its glazed or now.. is it dirty...etc..

This may help abit
http://vray.info/topics/t0039.asp

But now i dont think index of reflection is as set in concrete as index of refraction.

[jujubee]

Index of reflection (if there is such a thing) is one of those weird parameters I've only recently discovered myself. Perhaps it should be renamed something else like 'reflectivity'...

[s0real]

how about 'refelectivisation' ?

[DaForce]

I think the only reason its there is the IOR (refraction) used to be used to control reflection as well as refraction in previous builds and now that it has been seperated they left it as IOR (reflection) as thats what people are used too I guess.

It does strick me as odd tho. meh as long as it works.

[jujubee]

that label is really confusing to new people and old people alike and probably results in many a bad render. they should really change it...

'Freslectivity'?

[DaForce]

Im thinking "Fresflectionactuator"



This is getting silly

[RErender]

Blevins calls it "complex ior"