Reflection/ roughness

[Stinkie]

Could you guys please put the reflection and roughness sliders back in SkIndigo? I have no idea how many of the SkIndigo users found those useful, but I've always felt they were a standout feature. Better yet: aside from the the render quality, they were my main reason for buying Indigo.

Pretty please?

[Oscar J]

What are the advantages over IOR and exponent?

[Stinkie]

Ease of use and intuitiveness.

[Oscar J]

True. Though it's not scientifically based - maybe there could be an "advanced settings" checkbox if power users want the IOR/exponent sliders instead.

[Stinkie]

True. Though it's not scientifically based (...)

Probably not, but those sliders work really well, regardless. As far as I'm concerned, anyway.

(...) maybe there could be an "advanced settings" checkbox if power users want the IOR/exponent sliders instead.

That'd work for me, although -possibly- the other way around might be better. (As I'm guessing most Indigo users fall into the 'power user' category.)

[OnoSendai]

I think at some point we'll completely change exponent to roughness, both in the Indigo GUI and in the exporters.

[Stinkie]

Sliders.

[Oscar J]

Probably not, but those sliders work really well, regardless. As far as I'm concerned, anyway.

You can find IOR values for most common materials, but you can hardly find any "reflectivity" values. That's my main concern.

[Zom-B]

I think at some point we'll completely change exponent to roughness, both in the Indigo GUI and in the exporters.

Why switch and not allow both?
Older scenes will be broken if you switch, or is there a possibility to "convert" from exponent to roughness?
Even with a mapped exponent by a texture??!

[bubs]

Sliders.

love it
The slider request I get... I certainly used to use them all the time, (although personally I find the current system more accurate) but as for changing the system... what's the benfit?If it ain't broke and all that...

[OnoSendai]

I think at some point we'll completely change exponent to roughness, both in the Indigo GUI and in the exporters.

Why switch and not allow both?
Older scenes will be broken if you switch, or is there a possibility to "convert" from exponent to roughness?
Even with a mapped exponent by a texture??!

You can convert exponent to roughness, yes.
It is a bit trickier for exponent textures (or shaders).
It is possible in theory though.

[thesquirell]

Ease of use and intuitiveness.

I have to disagree with that, because the minute I started using Indigo this made perfect sense to me. Not to mention scientific accuracy you can get with it. IOR/Exponent system should be kept, or at least given as an option through a mentioned "advanced option" check box or maybe there could be something like a "simple mode" check box that would switch between IOR/Exponent current system and the new planned reflection/roughness. Currently, this system is perfect and I see no need for changing it. If people like sliders so much, they could be introduced as an additional mean of controlling these values, besides the numerical/texture/shader one, but the system in itself is brilliant, imho.

[Oscar J]

Bump. "Roughness" is probably a better term than "Exponent". "Exponent" is very abstract and I've never come in contact with the term in material properties contexts (IRL or rendering) outside of Indigo. Maybe it harks back to Indigo's younger days when they had their mathematic formulas for the reflections, and when varying an exponent to one of the bases in an expression changed the reflection roughness.


Roughness (from 0 to 1) has many advantages:

* Clear limits - From perfectly sharp reflections to a certain maximum roughness, and anything between. New users get an idea of the usable/useful range

* Relatable to percent and fractions and thus easier to communicate, like "twenty percent blurry" = Roughness @0.2.

* A more linear behaviour - the visual difference between exponent 100 and 1000 is far bigger than between 1100 vs 2000, as well as 100 000 vs 1000 000.

* Easier to take the step to Indigo from other applications.

* Less difficult and time consuming to read and write the values.

* The word "roughness" is much more concise and easier to relate to, while "exponent" can mean a million different things in math and physics.

Etc, etc.

IOR is a universal and well known term though. Definitely want to keep that.

[thesquirell]

I will have to disagree on that, because roughness from 0-1 seems harder to control over exponent values which range from 0-1000000(?). If I wanted to pick a roughness value equivalent of, let us say, 6430, or 235 exponent, or ranging from these values, controlled by a map, it would be harder for me to nail those numbers. I actually dislike roughness so much, that I want it removed from Double Sided Thin, and Coating types, being replaced with exponent.

[Oscar J]

Yes, but that's because you're so used to "exponent". The opposite is also true, if you want a certain roughness value, how do you know what exponent setting to use?

The problem is still this: what is "exponent" really? It's a little number in the Phong lighting equation which the vast majority of uses probably have never studied very extensively.