PBR kinda materials

[elindell]

I like the idea of adding CoronaPBRmat and keeping the old one for compatibility or preference.

[Nik]

I agree with people who wants separate PBR shader and leave CoronaMtl for backward compatibility. I want new, but I don't want to break old

[Juraj]

The current daily build did this very smartly, by adding (like another legacy) check-box.

Old materials render the same, unless you switch them manually and re-adjust (or maybe the converter will know how to do this).

New materials are created with correct behaviour (both fresnel and roughness range was fixed !! big hurray) . This is win-win solution.


Now the answer is where to go from here :- ) Improve this shader with more options like Redshift and AlSurface ? Or create another separate ?

Both options are viable. Although the first (extend current) would need another legacy check-box for glossiness-->roughness inverting. But as Dubcat shown, the Redshift shader has this in options of materials, so you can use both maps without selecting invert in map. Although that is pretty easy now too, since both are linear on range of [0, 1]

Maybe time for some OSL support, so we can create our own shader prototypes :- )

[romullus]

I think best way is to leave CoronaMtl as it is now and to introduce new CoronaPBR material with metalness, roughness etc, which could take input maps directly from Substance designer, DDO and alikes.

[Nik]

I talked with Ondra yesterday and he said that pbr checkbox will be probably merged to Legacy checkbox and I agree that this will be cleanest solution for glossy curve.
But right now legacy mode enables old nonGGX mode. Does somebody cares about nonGGX mode today? I think it can be replaced by "new legacy mode" that enables Corona1.4-like shading model and thats all. IMHO

I think PBR shader should be a separate material just to make sure that devs wont accidentally broke something in old CoronaMtl (keep back.compatibility in mind). But if they're sure that nothing will be broken then I don't care :)

We're all want new cool PBR material like in marmoset etc. with metallness, easy dependent spinners, coating and so on. Who used it know how easy and realistic they are.

1. Enhances CoronaMtl will force users to use new PBR workflow and deal with it (I'm sure pbr options will be enabled by default). I can't say this is good.

2. New CoronaPhysicalMtl would let people decide how to work and smoothly get new habits. Also Converter devs will thank you for that :)

[Juraj]

Agree there, "PBR" check-box can definitely be merged with current legacy. The old Ashikmin and the slight albedo-darkening is absolutely unnoticeable compared to "wrong GGX/Fresnel", so both can exist as legacy.

[pokoy]

Agree there, "PBR" check-box can definitely be merged with current legacy. The old Ashikmin and the slight albedo-darkening is absolutely unnoticeable compared to "wrong GGX/Fresnel", so both can exist as legacy.

I had some scenes where the darker albedo made a hell of a difference.

I have to say I still fear the legacy checkbox thing as much as I ever did - a fix to a fix of a fix etc... It would be far more controllable and user friendly to have a simple dropdown for the shader behavior, like 'shading model 1.0, 1.2., 1.4' etc, at least I'd know what legacy means exactly.
Then, at some point I'd rather have a clean cut, with the promise of never ever remapping channel response curves and another 'shader fix' with every point release. Hopefully we're at this point now.

[Nik]

Well, "Legacy mode" dropdown is very nice idea, but I suppose devs won't like it :)

[Juraj]

Agree there, "PBR" check-box can definitely be merged with current legacy. The old Ashikmin and the slight albedo-darkening is absolutely unnoticeable compared to "wrong GGX/Fresnel", so both can exist as legacy.

I had some scenes where the darker albedo made a hell of a difference.

I have to say I still fear the legacy checkbox thing as much as I ever did - a fix to a fix of a fix etc... It would be far more controllable and user friendly to have a simple dropdown for the shader behavior, like 'shading model 1.0, 1.2., 1.4' etc, at least I'd know what legacy means exactly.
Then, at some point I'd rather have a clean cut, with the promise of never ever remapping channel response curves and another 'shader fix' with every point release. Hopefully we're at this point now.

I think we might be. This corrected Corona Material could be the clean cut that behaves same as PBR, but with traditional controls. I am very satisfied with this solution, old scenes work, new materials also.

Regarding the Albedo darkening, I thought it was just unphysical hack, now the material behaves correctly, and people simply need to learn correct Albedo values. (hint: they soon won't need to :- ) ... )

The legacy dropdown is cool idea, like Windows, but I wonder how hard it would be to maintain, and what unpredictable issues it could cause in scene.

[Rhodesy]

You're such a tease! Is this anything to do with that beta software your testing?

Agree there, "PBR" check-box can definitely be merged with current legacy. The old Ashikmin and the slight albedo-darkening is absolutely unnoticeable compared to "wrong GGX/Fresnel", so both can exist as legacy.

Regarding the Albedo darkening, I thought it was just unphysical hack, now the material behaves correctly, and people simply need to learn correct Albedo values. (hint: they soon won't need to :- ) ... )

The legacy dropdown is cool idea, like Windows, but I wonder how hard it would be to maintain, and what unpredictable issues it could cause in scene.

[Juraj]

Yeah, but unfortunately I spoke to soon. The fresnel still needs fix. Now it has black halo.

[vkiuru]

I remember this darkening of the edges thing from other renderers' development stages also. Might be that PBR is too new to be related to said earlier ones but still funny to see it appear once again :)

[maru]

First we had a dark halo. Users complained. Then we had a bright halo. Users complained. Now we have a dark halo again. User complain. Come on people! Make your minds up!

But seriously, this needs a fix and I can assure you the team is working on it.

[romullus]

And what makes you think that users will stop complaining when this will be fixed? ;]

[Juraj]

I would laugh, but I can't :- ). Ondra made the same joke about bright and dark halo, but the F-Storm developer fixed this in two days. They have correct fresnel, full range, and even glossiness attenuation towards edge (change of glossiness towards sharper specular).

There are better options that Art Physical material, which won't work as should without the fresnel anyway (it will be just redressed CoronaMTL right now), although at least this will have unexpected benefit, we will be able to render with Corona and Vray the same scene.