Why does clear glass appearing as shiny black in material editor sample slots?

[JezUK]

Something I'm now experiencing in V-Ray is that glass material (from Cosmos library) looks polished black.

My own glass from my own personal library is clear glass looking preview (right most in attached image).

Cosmos glass is the one in the middle and another glass from a purchased model is the selected slot (also looks like black plastic in material editor slot).

All glasses render correctly - it's just this misrepresentation in the material slots which I'd like to address.

Any ideas?

[vladimir_krastev]

Hi, thanks for posting. Do you have different than completely white fog colour in your materials? If yes then it is normal. It is specific to the material editor preview that is done for performance optimisation. We are looking into ways to upgrade this further.

[hermit.crab]

Fog color, which depends on the scale of the object, maybe? What's the name of the glass from the Cosmos library?

[JezUK]

Fog color, which depends on the scale of the object, maybe? What's the name of the glass from the Cosmos library?

Glass Tinted Gray #0

[JezUK]

Yes, it's the non-white Fog Color that does it.

[fixeighted]

imho there is no real point in trying to gauge material properties this way, other than to get a quick visual reference of generally what the material is.
The representation is just too....unrepresentative in most cases, leading to confusion/sanity checking
I can't imagine it being able to be any better implemented either, as just for something like this, fog depending on scale would need some custom shaderball type mesh in the editor in order to judge the effect.
So that, plus the massive hit from using the Vray version of the swatches, is way too slow for anything but the simplest of scenes.

Using the ipr is by far the simplest way to get things set up...for me anyway

[JezUK]

imho there is no real point in trying to gauge material properties this way, other than to get a quick visual reference of generally what the material is.
The representation is just too....unrepresentative in most cases, leading to confusion/sanity checking
I can't imagine it being able to be any better implemented either, as just for something like this, fog depending on scale would need some custom shaderball type mesh in the editor in order to judge the effect.
So that, plus the massive hit from using the Vray version of the swatches, is way too slow for anything but the simplest of scenes.

Using the ipr is by far the simplest way to get things set up...for me anyway

Of course, I'm just saying it needs to look more like glass (like it does in the Cosmos Browser), and less like a black billiard ball

[fixeighted]

Ah yeah, ideally that would be the case.
My thinking was more that refractive materials (including sss and other special shaders) are so very varied that it'd be impossible to get a suitable representation for them within
the mat editor (and thus for the Cosmos viewer), so a generic thumbnail suffices as a starting point for reference

[vladimir_krastev]

The material editor previews are generated in an small external vrscene and depend on the way this scene is set up. And it is done like that for performance optimisation reasons.
The Cosmos Browser uses different preview.
We are looking into ways of improving the material editor preview in the future but for now this is the reasonable compromise that we could achieve.