To Iray Metalicity or to not that is the question

Szark

I was aksed to split this conversation off from PBS Metals , Metallic Plastics and Paints shaders for Iray [commercial]   

I said: In Simple terms having the Metalicity slider takes care of Gloss Weight, Reflection Weight, Anisotropy making them all redundant so you only need to deal with Roughness.  

MEC4D Said: That is almost true Szark , As I mentioned before sliding sliders for the eye is not PBR .. each material has specific standard measured level of reflection  that is the same for all PBR rendering ( not Gloss = roughness ) if you don't have proper metalicity maps you doing it for the eye , then you change the light and you do it again .. correct PBR values are always the same no matter the level of light brightness and btw Gloss is roughness of reflection, Reflection is specular .. 

I replied: I have to admit I don't have this pack yet so I haven't seen your settings. So what I can make out is that you don't use Metalicity but instead set up everything manually in line with PBR? 

So Metalicity is just a quick and dirty way to achive a metal look> Best to set up the shader using PBR standards maunally or buy MEC4D's shader pack/s. :)

DoctorJellybean

Szark said:

So Metalicity is just a quick and dirty way to achive a metal look> Best to set up the shader using PBR standards maunally or buy MEC4D's shader pack/s. :)

Quite often some surfaces which are metal include a texture. If a metal shader is applied, those textures are removed. So in this case I apply the Iray Uber Base and change the Metalicity to 1. Hopefully that is right

Oso3D

DoctorJellybean: Well, first, ctrl-click to preserve image maps. Second, apparently... no, that's not the 'right' way.
 From what I gather, metallicity is essentially a fast/inaccurate way to get the look of metals and reflective surfaces.

Also, I think most of us need to learn what the heck fresnel is, because apparently it's a critical element to accurate surfaces. (I had always just assumed it was mainly useful for wet layers)

 

DoctorJellybean

Well yes, I have tried ctrl-click to preserve the image maps. Somehow that doesn't work quite nicely, maybe that's just me.

maclean

I use Spec/Glossiness for most of my shaders, unless I specifically need a metal effect. Glass, ceramics, plastic etc, all look better (to me) with Spec/Glossiness. But in the end, it's whatever works for you.

mac

PS I may be biased because I picked up most of my Iray tips from Catherine (MEC4D). But I did read all the docs (DAZ & Nvidia) extensively.

Szark

DoctorJellybean said:

Szark said:

So Metalicity is just a quick and dirty way to achive a metal look> Best to set up the shader using PBR standards maunally or buy MEC4D's shader pack/s. :)

Quite often some surfaces which are metal include a texture. If a metal shader is applied, those textures are removed. So in this case I apply the Iray Uber Base and change the Metalicity to 1. Hopefully that is right

" Metalicity to 1" Yeah that is what I am refering, not the metal MDL examples but the Uber Iray Base. 

Szark

timmins.william said:

DoctorJellybean: Well, first, ctrl-click to preserve image maps. Second, apparently... no, that's not the 'right' way.
 From what I gather, metallicity is essentially a fast/inaccurate way to get the look of metals and reflective surfaces.

Also, I think most of us need to learn what the heck fresnel is, because apparently it's a critical element to accurate surfaces. (I had always just assumed it was mainly useful for wet layers)

 

I always use Top Coat fresnel and IOR when needed.

So what base does MEC4D's metal shader use, the Uber Base?

Gr00vus

My understanding is that in Iray, fresnel gives you reflections/specular/gloss (depending on which part of shader you're setting to fresnel) on the angles of parts of objects that are somewhat orthagonal to the camera. In situations where it seems the depth isn't quite there that I'd like, I've been setting top coat in the iray uber shader to fresnel and experimenting with the strength to give better depth via highlights on the angles. It's been useful in making hair look better as well as skin shaders. Here's a brief article about fresnel in 3d rendering in general (not Iray specific).

timmins.william said:

Also, I think most of us need to learn what the heck fresnel is, because apparently it's a critical element to accurate surfaces. (I had always just assumed it was mainly useful for wet layers)

 

 

Oso3D

Szark: Her metals are spec/glossy with top coat fresnel.

I was very confused because my limited exposure to IOR and such, I thought of it mainly in terms of volume effects, with IOR from 1-2, and occasionally higher. Surfaces, on the other hand, are completely different.

I don't think most newbies (like myself!) understand the role of fresnel in physical rendering.

 

MEC4D

Szark what Uber base ? Uber base is a material room that have 3 base shaders style, in most cases Metalicity, glossiness/specular and weighted 

no matter what you use you can get exactly the same result but each style need different settings .

Under Metalicity Diffuse is  Specular at last when Metalicity is set on 1  with a proper map .

I don't use Metalicity as for me is not possible to get all PBR values for that and all programs that do create the maps are not calibrated for DAZ studio or Iray .

Don't forget that my shaders are commercial product and settings can't be shared in public .

I do use Glossiness/specular as I use it for the last 17 years and have no reason to change if I don;t have to.

I do my shaders the way I do because it allow me to make different layers that can be mixed together what would be not possible with Metalicity shader style

Metalicity is not quick dirty way to do things , you still need the correct maps and without proper values you get nowhere closer to PBR no matter what shader style you use all need the same attention .

Everything has Fresnel any surface , whwn you look at the angle you see the light reflecting when you look on object from top the surface is clear from reflection just  like you look at water or plastic or all other stuff .

You can do all yourself and for those that don't have 3 months on research it is up in  the store as good as you can get lol

I hope you got informed , the subject is old as the community with thousand threads on this around the internet it is the main basic ..  go study and learn your stuff if you need.. I don't have to do it anymore it is up in my head already and kinda in the middle of my project but will drop  in later to see what's going on with you gurus ;P

Szark said:

timmins.william said:

DoctorJellybean: Well, first, ctrl-click to preserve image maps. Second, apparently... no, that's not the 'right' way.
 From what I gather, metallicity is essentially a fast/inaccurate way to get the look of metals and reflective surfaces.

Also, I think most of us need to learn what the heck fresnel is, because apparently it's a critical element to accurate surfaces. (I had always just assumed it was mainly useful for wet layers)

 

I always use Top Coat fresnel and IOR when needed.

So what base does MEC4D's metal shader use, the Uber Base?

 

MEC4D

You always need fresnel for everything  in  PBR and not just when you need it , reflection and glossy will not always give you the right effect, fresnel always will 

I use PBR Specular/Glossiness and all old DAZ Studio maps from the past and present are made for  Specular/Glossiness until recently people started to make some metallicity maps for Iray 

but anyway, there is no difference if both shader styles are set correctly .. so not like one is better than  the other .. as both can be set with PBR values .

Szark said:

timmins.william said:

DoctorJellybean: Well, first, ctrl-click to preserve image maps. Second, apparently... no, that's not the 'right' way.
 From what I gather, metallicity is essentially a fast/inaccurate way to get the look of metals and reflective surfaces.

Also, I think most of us need to learn what the heck fresnel is, because apparently it's a critical element to accurate surfaces. (I had always just assumed it was mainly useful for wet layers)

 

I always use Top Coat fresnel and IOR when needed.

So what base does MEC4D's metal shader use, the Uber Base?

 

Szark

I was just interested in what base you sued that was all. I agree with you using the correct maps etc and getting the same results with whatever base is used. I just stuck with the Roughness base as it was more inline with other shaders. I find it easier then the Glossiness/Spec base. yeah like 3DL but more challenging in setting up for me. :)

 

Oh I never mentioned about redistributing your shaders but more of buying them to educate myself futher and saves me doing them myself for my own renders. :P

 

makes me wonder why the Fresenl isn't in the main rougness channel instead of just top coat.

Szark

timmins.william said:

Szark: Her metals are spec/glossy with top coat fresnel.

I was very confused because my limited exposure to IOR and such, I thought of it mainly in terms of volume effects, with IOR from 1-2, and occasionally higher. Surfaces, on the other hand, are completely different.

I don't think most newbies (like myself!) understand the role of fresnel in physical rendering.

 

it all in the process of learning, once you get the basics down you start looking into thngs like this, for me just a natual progression but I am starting to hits my educational limits of the math involved or even where to find such information that is in laymens terms and therefore understandable. :)

MEC4D

The base shaders are created in layers, top coat is almost the same than the other, it just have more functions to choice from, and since fresnel is the last thing you see on any surface that why they put it in top coat , you can skip all layers bellow and go from diffuse to top coat .. just because the layer name is Top Coat mean nothing, you can call it layer  #7 or whatever , DAZ programmers called it to make it easy to follow .. 

before you had 2 specular levels now one is called specular and the other top coat .. but you can choice reflection in top coat function if you need so .. it does really no matter unless you build complex shader preset and take advance of it as I did in my PBR vol.1 where 2 shaders preset can be merged into new one .. but only under specular/glossiness because when using metalicity for metal you can't really merge it with another shader presets and btw any metal surface that does not have black diffuse is no metal under PBR  , only pure metals are PBR or when mixed with another layers on top ..  

now example

you haven a shiny chrome under metallicity now you want to add layer of rust  on top.. oh shut  there is no  second diffuse to plug the rust diffuse map into as the main metalicity diffuse is already taken and working as  specular for the chrome metal ... now you know why I prefer Specular.glossines to take the advantage of the layers and do more .. the second choice you have to buy expensive program that  will do it for you and generate all the needed metalicity maps with PBR values correctly but the result will be final .. rust on top of chrome ..as one shader preset

 

Szark said:

 

 

makes me wonder why the Fresenl isn't in the main rougness channel instead of just top coat.

 

Szark

for people you want to learn more about Metailicity and PBR in general this was informative https://forum.sketchfab.com/t/tutorial-pbr-and-metals-technics/2070

Metalness - Metalness is the trick here, how does it works? It simply creates a specularity based on the diffuse color, so if you put it on the highest value and have a black diffuse, it will not work. If you put a cool gold color on the diffuse, it will generate a golden specularity on it. That is the secret while using Metalness. At the time that I didn't know how to use it, I randomly picked some number until reach some cool results.

Then these two

https://www.marmoset.co/toolbag/learn/pbr-theory

http://www.marmoset.co/toolbag/learn/pbr-practice

MEC4D

the 2-second links are very good to learn basic, just don't mix specular/glossiness info and values with metalicity they are both different so choice one and focus on that skipping the other or  you get lost .

the  most examples from the 2 links are based on specular since the subject is for much longer in practice.

Szark

Thanks yeah I don't get confused with the two bases Gloss/Spec and Metal/Roughness I just prefer the Metal/Rough base. But as you say the Gloss/Spec is pretty much the same as 3DL in some ways. I do understand the basics of PBR and have so for a while now. I was just interested in your set but needed to make sure before I spent what little money I have. Also I want to learn....more. :)

MEC4D

Gloss/Spec  is the basic in 3D in most all programs , Metalicity was invented not too far ago by Disney so they can see the metals colors in the viewports before rendering and also limit the amount of texturing used, they also invented the PBR value charts they go with but the problem now is that each program read it different way and without proper calibration it don''t works exactly the same way , even Gloss/Spec from Vray will render different in Iray 

The path is not simple but worthy learning 

 

Oso3D

Now I'm thinking I ought to make a second version of my procedural shaders based on Spec/Gloss shader. Oy. That's a lot of work. hmm

Thanks for all this info. I had no idea metalicity made diffuse into specular. Oooh.

MEC4D

Yes it use the diffuse as specular color for the metals , and to tell tou the truth I could never set my skin shaders correctly using metalicity , it just did not worked  for me , sometimes by mistake I choice the wrong style thinking what is going on until I realized I am unnder wrong shader style . It is worthy trying as your knowledge from using 3DL will be not lost completely  

timmins.william said:

Now I'm thinking I ought to make a second version of my procedural shaders based on Spec/Gloss shader. Oy. That's a lot of work. hmm

Thanks for all this info. I had no idea metalicity made diffuse into specular. Oooh.

 

Szark

PBR Roughness seems like the new standard for many programs while some are still staying with the Gloss/Spec mode. I suppose it is a personal choice.

kitakoredaz

 I am now learning too,,because,,,,  3d coat, offer three mode,, 1 diffuse + glossiness(specular)

2  metalicity, glosiness,    3, metalicity and  roughness ,  then User need to choose texture for each mode.when export them for another aprication.

when I use PBR materials in 3d coat, and custimize texture,,  I feel, I may better export maps as metalicity mode.

(though at fast,, I simply use,, diffuse and glossiness,, it seems more  clear for me ^^;)

 

but the 2 and 3  is really complex for me,, I understand each map  meaning,  and apply each map for uber iray (metalicity mode)

but I still can not manage them well,,  with uber iray shader (metalicity roughness mode)  correctly without loosing  the appearance which I see in 3d coat,,

 

THen,,  I do not know,, Nvidia use  the word " metalicity"  ,in their MDL  guide book etc,,, then I feel somehow strange,,

it mainly tell "diffuse ,glossy,  specular" and "reflect, transmittsion  emission",  then mix them by layer,

but I have never see "metalicity"  map or such  property,, in iray guide book.

 

Szark

I find the Roughness model easier to use for everything but the trouble is that the metal diffuse map must be the correct colour when using Metalicity...using the Gloss/Spec mode negates this fiddly issue as you are controlling colour via the gloss/spec colours.

kitakoredaz

Yes,, I understand,,,  and metalicity texture should be set with metalicity strongness = 1.00 (I feel so) (DoctorJellybean  said above,,)

then metalicity texture ( non color data)divide,, metal section and  non metal section (diffuse main or mixec)  , then

shader use base color as  diffuse color ,, or for specular color  or mix ,, with the metalicity  ratio,, I feel,,

 

but I had never used,, roughness map ^^; then it somehow confuse me,,, about this case,, rougness value  need to set 1.00 as same as metalicity ?

 

 

Szark

Yes the way I see it working is yes Metalicity 1.00 and Roughness map set to the correct gray scaling and set to 1.00 but a roughness map is only really needed if there is variation is roughness across the surface. Otherwise just use a value. Also a roughness map is the inverse of the old spec maps, white being more rough and black being smooth.

kitakoredaz

Thanks confrim,, then when use roughness texture,, do you  set glossy color  value as 1.00  with no texture?   or keep 0.85 0.85 0.85 ?

(and,,, there are two roughness for glossy and diffuse,, ^^:: then,,,do you apply both? or simply apply

roughness texture  just for glossy? I ignore, diffuse roughness at current,, but seems not correct,,,I feel,,)

Szark

With the Metalicity/Roughness model you keep gloss colour white for everything. As changing it to grey will just make the effect lower and not grey. However with Metalicity set to 1.00 Gloss Weight and Colour are redundant, only roughness counts,

 

Diffuse roughness is more for things like clay, untreated terracotta earth etc etc.

kitakoredaz

 when metalicity 1.00 , with metalcity strenght texture,,(multiple),, the gloss weight and colour are ignored too?  (I feel so,, but feel strange,,

because,, actually,, on each pixel,, metalicity  not 1.00 (multipled with texture data ^^;  )

 

then,, about diffuse roughness,, there should be part which diffuse roughness contribute,,,I feel,,

eg,, I make one texture for swimwear,,for , metalic part (actually plastic like) and cloth part,,  these parts island are clear separated, then  I may need only one texture,,,for each map. then 3d coat export,, with the metalicity, roughness mode,,

usually,, base color map,, rougness map,, normal map, metalicity map.. then I feel,, roughness for diffuse (of course,, it is almost low value)   may need to appy for not metalic area too. though I do not know clear,, ^^;

Szark

yes whe Metalicity is set to 1.00 gloss weight and colour are ignored for the parts of the metalicity weight map that are white, ie METAL, the gray and black parts ie NON METAL, of the map will use the Gloss Weight and colour as normal. Yes this approach is great when you have one map for all surfaces, so you can define the metal parts from the rest using strength maps. This is why I love the roughness model

Oso3D

It can also be fun to create roughness with very highly tiled bump maps.