Meaning of the term 'glossiness' = sharpness or softness

[tricky]

Since starting out with VRay many, many moons ago, the term 'glossiness', to me, has meant 'blurriness'. In other words, a material with very glossy reflections means that it has very blurry reflections. Or a material with slightly glossy reflections means that it has slightly blurry reflections. A material without glossy reflections has sharp, mirror-like reflections.

Is this how you understand it?

Many clients and artists seems to interchange the meanings which has lead to me questioning my own understanding!

Please let me have your understanding.

[Rens]

A material without glossy reflections has sharp, mirror-like reflections.

Correct, however increasing the glossiness spinner will give it more mirror-like reflections, so you could say that when you increase the glossiness you make the reflections sharper.
It's confusing and not very logical, a better name would be roughness or smoothness depending on if you want to go positive or negative for mirror-like reflections. (Also, technically specular reflection is another name for mirror-like reflection, adding more confusion).

[Morne]

Yes that is how I also understand it from a lot of tutorials and explanations.
"In VRay if something is glossy, it has very blurry reflections" (BUT that is the wrong way of wording it because if you INCREASE glossy reflection it becomes less blurry)

A lot of tutorials refer to the more glossy a material is (the more blurry), the more you have to INCREASE your subdivsions when in fact it is the other way around. Glossy means shiny (mirrors etc)

Just think of real life when a client refers to a glossy tile, they mean it is very shiny (like a mirror)

[Raven]

Hey Richard

No, to me glossy has always been, the higher the value. ie 1 for 100% the smoother a surface.
You add a gloss coat to car paint. Glossy photos, are shiny and reflective. Matt are not.
So to me it does not mean blurriness, yes the setting it controls how blurry something is.
But if it where a blurriness setting the spinner would work the other way. ie a value of 0 would be a mirror finish, 1 a matt finish.
That's my take.

[Dariusz Makowski (Dadal)]

Hey Richard

No, to me glossy has always been, the higher the value. ie 1 for 100% the smoother a surface.
You add a gloss coat to car paint. Glossy photos, are shiny and reflective. Matt are not.
So to me it does not mean blurriness, yes the setting it controls how blurry something is.
But if it where a blurriness setting the spinner would work the other way. ie a value of 0 would be a mirror finish, 1 a matt finish.
That's my take.

I agree with this one.

Glossy = reflective/highly sharp.
Matte = blurry reflections

Less glossy means its less reflective in my understanding and more matte means its more blurry... They are confusing aren't they

I think people confused this over years and now is misleading.

[vlado]

When we implemented the VRayMtl material, we took the parameter name from the Standard material in 3ds Max, which has a parameter called 'glossiness' and works in a similar way as the V-Ray glossiness (higher values produce sharper highlights and a more mirror-like surface). With English not being my first language, I did not question the correctness of the term, I assumed that's what it's normally called Later on, the Arch&Design material used the same term in the same way as the Standard/VRayMtl materials, and still later on this seems to have propagated to other renderers as well.

Best regards,
Vlado

[Rens]

I think the confusion comes from the fact that in rendering when you talk about glossy reflections you talk about scattered reflections, not mirror-like reflections. Glossiness is technically correct for what it does in a shader (more glossiness = more mirror-like), however when someone working with shaders says he/she wants glossy reflections they're talking about getting (somewhat) blurry reflections, because that's the value you change to get that result. A client might mean glossy = mirror-like.

[rjohnson33]

I think it's a bit of an odd term still in comparison with how a client or the general public are most likely use it.
I think if someone uses the term glossy they're probably describing something between about 0.8 and 0.96 in VrayMtl terms but not above that range either.

For example I don't imagine anybody would ever describe a mirror or pane of glass as being 'glossy' whereas in the VrayMtl terminology they are the most 'glossy' (i.e. values towards 1.0).

[tricky]

Well at least I am not alone in my confusion with the term. After all these years, I was potentially going to embarrass myself big style.

The main reason I mentioned this is that quite often, I will issue a draft to our client of (for example) a kitchen with a wooden floor and granite worktop. They will say: "That looks lovely (!), but can you make the floor more glossy and can you make the granite a bit more shiny".

In my head, I then start thinking "OK, so my wooden floor has a glossy value of 0.8 at the moment. Should I reduce that to 0.7 or is the client thinking about glossiness in terms of sharpness, in which case, 'more glossy' could mean sharper reflections, in which case I'll have to increase my VRay glossy value to 0.9....on the other hand, he could simply be asking me to make it more reflective, so I need to change the colour value in the reflection slot, or adjust the falloff curve slightly. And then...hang on...I'm using the 'GW Approach' with multiple glossy orbs, so I will need to adjust the values in each of the blend layers and increase the subdivs to reduce the noise......."

Whilst this is going on in my head, the client is already talking about something else!

[Dariusz Makowski (Dadal)]

Well at least I am not alone in my confusion with the term. After all these years, I was potentially going to embarrass myself big style.

The main reason I mentioned this is that quite often, I will issue a draft to our client of (for example) a kitchen with a wooden floor and granite worktop. They will say: "That looks lovely (!), but can you make the floor more glossy and can you make the granite a bit more shiny".

In my head, I then start thinking "OK, so my wooden floor has a glossy value of 0.8 at the moment. Should I reduce that to 0.7 or is the client thinking about glossiness in terms of sharpness, in which case, 'more glossy' could mean sharper reflections, in which case I'll have to increase my VRay glossy value to 0.9....on the other hand, he could simply be asking me to make it more reflective, so I need to change the colour value in the reflection slot, or adjust the falloff curve slightly. And then...hang on...I'm using the 'GW Approach' with multiple glossy orbs, so I will need to adjust the values in each of the blend layers and increase the subdivs to reduce the noise......."

Whilst this is going on in my head, the client is already talking about something else!

More glossy in clients mind is usually a cross between more reflective and sharper reflections. More shiny means more matte and slightly more reflection... Thats at least whats in my head

[Neilg]

Something real world glossy is sharp and reflective. You increase the value of the glossiness in vray to make it sharper.
always seemed right to me.

Nobody would describe a mirror or glass as glossy because it's perfectly sharp and doesn't register on their scale. They would never expect to have to use those terms, we all know they're sharp. (plus 1=basically turning it off, the word isn't used anymore)

[tricky]

Something real world glossy is sharp and reflective. You increase the value of the glossiness in vray to make it sharper.
always seemed right to me.

Nobody would describe a mirror or glass as glossy because it's perfectly sharp and doesn't register on their scale. They would never expect to have to use those terms, we all know they're sharp. (plus 1=basically turning it off, the word isn't used anymore)

What about gloss paint then?

When I used to get my filmd developed at Max Spielman I was asked if I wanted gloss or matte finish. Gloss was mirror like.

[^Lele^]

Gloss in real life, Geometric Optics terms, means sharp, as far as reflections go.
It stands to reason that a Glossiness of 100% (1.0) should produce mirror-like reflections (ie. the reflections cone angle is 0 degrees, one ray is enough), whereas a glossiness of 0% (0.0) should produce a diffuse-like reflection (ie. the cone angle is 180 degrees above the shaded point, making it much similar, if more complex a shading math, to brute-force GI).

The fact that in common situations one would name a material "Glossy" only when its value is below 1.0 (so to all effect making it less than perfectly glossy) has to do with a "binary" language logic switch: it really means the VARIABLE glossiness calculations are active, and more rays will be needed, less bounces, and so on and so forth.

[hoppergrass]

Master Zap did an interesting poll about this on his blog http://mentalraytips.blogspot.com.au...oll.html#links

[Neilg]

What about gloss paint then?

When I used to get my filmd developed at Max Spielman I was asked if I wanted gloss or matte finish. Gloss was mirror like.

That's the same thing, more gloss makes it sharper. it's just that's at .99. a mirror is 1, which is not glossy - it's a mirror.
e: lele explained this better than me