Does PBR make specular amount maps obsolete?

[dgruwier]

Since IOR already represents the reflectivity of the material, it seems to me that a specular glossiness map in an energy conserving shader is all that is required to have accurate reflections on that object right? And if you need to blend between materials, you'd use a texture to blend between different IOR values?

I'm asking because I often get a specular amount AND a specular glosiness map from texturing, and things always look better if I just discard the specular amount texture, or incoporate it into the specular glossiness texture. I also notice that most 3D scans only come with roughness and not amount.

Any thoughts?

I should note that this is also often called specular/reflection color, including in VRay materials, but I'm avoiding that term because I'm talking about greyscale maps.

[Grigio18]

I also don't put any texture into reflection for all dielectrics.
the Gloss map and the check on glossy fresnel plus the right IOR, seem to give better results and i am happy to remove a map that is always an extra ingredient to manage.
The reasoning is, The reflection color indicates the maximum reflection value (which as far as I know should be 100% for all dieletrics)
The IOR should represent the reflection curve, from the minimum (normal to the surface), to the maximum (90 ° with respect to the surface).

we should have enough parameters to make a correct material, don't we?

[MANUEL_MOUSIOL]

I am using a lot of cgaxis models and while the modelling is good the materials make my teeth gringe. I have to go through every material correct it. 8 ior for wood?? 12 for ceramic. Makes me crazy and the materials don't behave like they should.

The only time there is a reason to reduce specular amount (reflection intensity) is when you have something like a carpet, an object that swallows a lot of light, but you didn't model it like that and are only using a plane e.g.
Or for artistic reasons or a quick fix obviously

[Ihno]

I am using a lot of cgaxis models and while the modelling is good the materials make my teeth gringe.

Also, strange scanline shellac materials which reflect more light than they get. Noise generators basically. Its like the want to make it wrong, looks like they put extra effort in to break it.

[MANUEL_MOUSIOL]

Haha yeah, its terrible. I think they never evolved their old workflow. Their renders look nice enough in their preview setup but that's all the materials are good for. Any other setup and things go downhill.

[^Lele^]

I also generally kept things as simple as humanly possible, and relied on good geometry for complex looks.
Reflectivity amount maps however may help when there isn't a second shader one's blending with (with two shaders of course the amount map would be the blend amount instead of the reflection amount.), and/or when the model doesn't carry enough info on the geometric side (and so likely the amount map would also control other material parameters, to simulate the appearance of two blended shaders with a single one.).

[MANUEL_MOUSIOL]

Exactly. If you want to do two materials in one.
I'm almost exquisitely using vrayblend these days for that.
Scanned textures and pbr materials are a different horse obviously.

[DanSHP]

I am using a lot of cgaxis models and while the modelling is good the materials make my teeth gringe. I have to go through every material correct it. 8 ior for wood?? 12 for ceramic. Makes me crazy and the materials don't behave like they should.

The only time there is a reason to reduce specular amount (reflection intensity) is when you have something like a carpet, an object that swallows a lot of light, but you didn't model it like that and are only using a plane e.g.
Or for artistic reasons or a quick fix obviously

We bought 3 CG Axis tree packs on sale a while ago and created a rather large forest pack library! It dawned on me not long afterwards that the materials were absolutely awful.

When we have time, we go through each tree in the library and update the materials for each one. Tedious. Wouldn't buy from them again.

[piotrus3333]

I use sometimes cavity maps in VRay’s specular slot. grass, carpet etc.

[MANUEL_MOUSIOL]

Is that like a dirt or curvature map?
what exactly are your achieving with it?

@danshp
True, I have an unlimited plan which I got for a huge discount so just for getting models its fine. But do you know a better source for models? Especially when it comes to decoration and furniture?

[piotrus3333]

Is that like a dirt or curvature map?
what exactly are your achieving with it?

@danshp
True, I have an unlimited plan which I got for a huge discount so just for getting models its fine. But do you know a better source for models? Especially when it comes to decoration and furniture?

sort of. shows very small occluded places light does not get to so much.

[MANUEL_MOUSIOL]

So you use it to make these places less glossy or reflect less?

[piotrus3333]

reflect less or not at all.

[MANUEL_MOUSIOL]

And why not make it totally glossy? Still too bright?

[piotrus3333]

it should affect amount of light reflected by object. so diffuse and reflect. not glossiness of its surface.