[tom]

Great test Mihai!
Cylinders are nice idea....

[tom]

angmac,

I follow and understand your rightful curiosity about plastic material's sufficiency and complex IOR. I see there are great tests going on here and all are quite beautiful. Well, in new material system you'll find more controls over physical phenomenons to control the surface behaviour better for sure. Now, I can't tell more details but I'm sure that you'll enjoy the release and new system.

Best regards,
Tom

[tom]

angmac,

Well, I understand you but it's not wrong that maxwell is physically correct. Imagine the real life has infinite detail to calculate anything and this is practically not 100% perfectly possible, yet. Regardless for any engine, there's nothing perfect to simulate real materials with all physical apsects if you also think their chemical properties etc. Currently, Maxwell is doing this very well and honestly I'm not the one to say this. You may view the results in the site gallery and figure out the difference easily. What I told about the release, it will give you more controls over physical facts. So, this doesn't mean it's not correct now, just not complex enough. It's something like you can't make multicolor dielectrics right now. Tomorrow you will demand rendering nano details maybe, don't you? So, there you'll find great things in time for sure. Always improvement, as in every other software and thing in life...

Best regards,
Tom

[j_petrucci]

:sigh: Not only do we get no updates, but we can't eve get a screen shot or description of the material editor. Thanks NL.

[Micha]

... for dielectrics the same, the fresnel effect looks very light.

[Micha]

... today I have searched for some infos about the specular value of ceramic and find some ceramic images here. I think, this are some more example that something is wrong with the fresnel effect:

[daros]

I agree with mihai, the blurriness of a reflection depends from the distance from the reflectiong point to the reflected point. It not depends from the incidence angle. The illusion of the sharper reflection with a smaller reflection angle is caused because the reflection results stronger, but not sharper, caused by the fresnel effect.

The sharpenss of an anisotropic reflection depends from the anisotropic vector direction in relation to the axis PointofView-Taget. If the anisotropic vector is parallel to the axis PointofView- taget the reflection will be sharper. If it is transversal it will be burred.

[Micha]

I agree with mihai, the blurriness of a reflection depends from the distance from the reflectiong point to the reflected point. It not depends from the incidence angle. The illusion of the sharper reflection with a smaller reflection angle is caused because the reflection results stronger, but not sharper, caused by the fresnel effect. ...

Hmm, in my world I see this effect. But somebody has say: we only see, what we want to see.

Today I have looked in the maxwell helpfile. Tom's plastic spheres dosn't show a fresnel effect too. Only if I want to see it, I see a very slight effect. I'm very curious on the final Maxwell.

[CHRiTTeR]

Anisotropic highlights (thus reflections) and fresnel reflections are 2 VERRY different things. I'll post examples as soon as my current renders are done...

And YES fresnell reflections are a MUST-HAVE-THINGY for ANY renderer now-a-days, surtainly for Maxwell. Such a nice renderer and you're telling me it doesnt do fresnell reflections? Every renderer has fresnel (including all the standard renderers that I know of).
To be honnest and with all rspect, I think it would be a major flop if maxwell doesnt have fresnel reflections. It adds TONS to a realistic look for a material. How do you guys make your carpaint in maxwell without fresnel???

I was thinking about purchasing Maxwell, but if it doesnt fresnel, I will sertainly not buy it.

Just out of curiosity? I hop you guys can adjust the IOR of your transparent materials? If not, how do you guys distinguish transparent plastic from glass? (I'll post an examples of this too)

Seems to me that Maxwell isnt that realistic as it claims... pitty
Or will there be adjustable fresnels reflections and IOR in the final release?

[Kabe]

And YES fresnell reflections are a MUST-HAVE-THINGY for ANY renderer now-a-days

Do you really think the NL coders have no clue about Fresnel? You MUST be kidding...

Fresnel reflection happens in *dielectrics*, and goes to 100% if viewed flat. In fact this is what it does in M~R, too.

This is *not* true for Plastic, and believe it or not, this is correct physical behaviour.

One of the few hopes I have for the new release is a great material engine, that allows great control about the physical properties.

Kabe

[CHRiTTeR]

And YES fresnell reflections are a MUST-HAVE-THINGY for ANY renderer now-a-days

Do you really think the NL coders have no clue about Fresnel? You MUST be kidding...

Yes, I find that also hard to believe. But why isnt there any IOR control then? Not all *dielectrics* have the same IOR you know.

Water (0° C) = 1.33346
Water (100° C) = 1.31766
Water (20° C) = 1.33283

Glass, Arsenic Trisulfide = 2.04
Glass, Crown (common) = 1.52
Glass, Flint, 29% lead = 1.569
Glass, Flint, 55% lead = 1.669
Glass, Flint, 71% lead = 1.805
Glass, Fused Silica = 1.459
Glass, Pyrex = 1.474

Crystal = 2.00
Diamond = 2.417
Emerald = 1.57
Ethyl Alcohol = 1.36
Beer = 1.34
Ice = 1.309

etc...

more rcontrolable colors and IOR settings for the metal material would be nice too.


Aluminum = 1.44
Bronze = 1.18
Chromium = 2.97
Copper = 1.10
Copper Oxide = 2.705
etc...

Fresnel reflection happens in *dielectrics*, and goes to 100% if viewed flat. In fact this is what it does in M~R, too.

100% when flat?!
U mean 0% when parallel (flat -> facing the camera) and 100% when perpendicular.

This is *not* true for Plastic, and believe it or not, this is correct physical behaviour.

Plastic DOES have IOR-based fresnel reflections.
And it seems u need to use the plastic material for far more then plastic alone (rubber, paint, leather,...) because there is no other alternatieve that gives u the needed options, thus u'll need an adjustable IOR get the *correct physical behavios*.

Plastic = 1.460
Rubber, Natural = 1.5191
Asphalt = 1.635
Pearl = 1.53
Polystyrene 1.55
etc..

One of the few hopes I have for the new release is a great material engine, that allows great control about the physical properties.

Kabe

I agree on that one
And I hope an adjustable IOR for reflections and refractions is available in the final version. Otherwise it wouldn't be a final version in my eyes (sorry, just my opinion).
But the fact that there are only a few metals and glasses available makes me think this is a limitation of the current version. Thus it makes me think all the IOR and fresnel stuff will be available in the full version, at leat I hope soo

Also I do hop verry much they have added some support for the procedural maps! Coz I work a lot with those.


More scientifical info about fresnel and index of refraction:
http://wufs.wustl.edu/courses/epsc407_2 ... 030128.htm

[macray]

But you have already found out that you can adjust the IOR for Dielectrics, have you?

[Dane]

Hi

Actually Metals have complex IOR : (n+ik), where k = (a*lambda)/(4*pi), where lambda is the wavelength and a is the absorptionskoefficient.
-And both n an k are wavelength dependent.

For copper I have : n=0,617 and k=4.258 at lambda = 589,3 nm according to my text book in Optics from the university.

-So life is complicated

BR Dane

[CHRiTTeR]

But you have already found out that you can adjust the IOR for Dielectrics, have you?

I have now (I think, still gotta test it), hahaha

But still i think it should be available for all materials that use relfections (and transpancy).

If they make it possible to use procedural maps then there wil be no more need for that btw, because then it would be controlable by a falloff map (in max, dont know how they call it in other apps)

[Kabe]

But why isnt there any IOR control then? Not all *dielectrics* have the same IOR you know.

Unbeeelievable! Different IORs! BTW in the Cinema plugin there is IOR control, so it's a plugin limitation, not a Maxwell limitation.

Plastic DOES have IOR-based fresnel reflections.
And it seems u need to use the plastic material for far more then plastic alone (rubber, paint, leather,...) because there is no other alternatieve that gives u the needed options, thus u'll need an adjustable IOR get the *correct physical behavios*.

We can certainly agree that the current material set is quite limited in that regard, however this is exactly the area where tom said we will see real progress.

So IMO it's definitly not that they wouldn't think about that, it's just not implemented in the "current" beta.

Also I do hop verry much they have added some support for the procedural maps! Coz I work a lot with those.

That is really hard to do in a cross application thingie, because they all have their own procedurals. You could have Maxwell procedurals though I hope.

Nice link btw

Kabe