Reflect/refract interpolation

[narmer_visual]

Hello ChaosGroup,

Has the function Reflect/Refract glossiness interpolation in VRayMtl been removed in VRay 3.50?
I can't find it anywhere.

Gabor

[svetlozar.draganov]

Yes, it has been removed.
Have you used it on a regular basis?

[Macker]

This will be the first time I've ever heard of anybody using it.

[narmer_visual]

No, I haven't really used it so far.

However I recently came to a problem, in which I had to work on a night shot of a building , with considerably large refractive surfaces with ~0.7 glossiness. Also had reflecting water surface in front of the building, so the reflection+refraction killed my render times.
It took 2-3 hours to render on 5 machines with DR in 2400x1350 px resolution, however, I tried to decrease the settings as low as possible, but to have no noise.
Generally I can not really afford these render times. So using interpolation would offer a nice alternative solution to decrease the render time to ~15 minutes if needed in these kind of situations, or in case of noiseless previews.

So if this solution is gone, is there something for glossy refractive materials, which may not be hyper realistic, but renders relatively quick?

I like to tweak the settings like: decrease max refraction depth to 2-3, make refractive objects invisible to GI, or not to generate GI in VRay Properties, etc.
These can decrease the render times by 10-20%, but that does not mean too much in some cases.

Thank you,
Gabor

[vlado]

It would be better to use the denoiser for this.

Best regards,
Vlado

[narmer_visual]

Dear Vlado,
Thanks for the suggestion. I haven't really tried the denoiser yet, but I will.

[davius3d]

I never used it (specially on videos - it's a source of infinite flickering) *but* right now we're rendering a scenario of a factory where the client wants all elements (machinery, hanging cables, wires, monitors, tubes, everything really) to have a glossy aluminum look. It does NOT have to be photorealistic, if the quality is in the hyperreal/illustrative side then we're good. In this case using reflection interpolation saved ourselves in render time - in a fraction of the regular time we get noise free smooth surfaces render.

I admit this is not a widely used feature. But one of the reasons I like Vray so much is that it is there in case I need it (as I did just now).

[narmer_visual]

I agree, maybe it's not really used often, but can come in handy in some cases. In my opinion it shouldn't be removed long as it is not bothering anyone, or if it's not causing extra work for the developers to maintain it.
This might be a case when a feature is not really used, but as soon as it's removed, users start to complain.

[vlado]

In my opinion it shouldn't be removed

It's already gone

if it's not causing extra work for the developers to maintain it.

It does cause us extra work to support it.

Best regards,
Vlado

[davius3d]

Gone like, for ever? Not accessible even through script?

[svetlozar.draganov]

Yes, they are completely removed not only hidden from the UI.

[Streetwise]

So if I come across a material that has reflection/refraction interpolation detected, how do I go about turning it "off"?

[vlado]

You don't have to do anything, V-Ray will just ignore those options and will proceed as though the options are turned off.

Best regards,
Vlado

[Streetwise]

Thanks for that. A client of mine says that instances of it in materials in older versions of V-Ray can sometimes result in splotchy materials and/or renders.

[jtswfr]

Hi Vlado, I'm with the client referred to in the above post. Can you verify - if a legacy *material* has reflect/refract interpolation turned *on*, the current V-Ray version (3.6+) will ignore those options when *rendering*?
Thanks!