PLEASE bring back prepass mode for VrayFastSSS2

[ben_hamburg]

So, after dreading the step for years, we finally upgraded to Vray5.
Worst case scenario has happened though:
Our rendertimes for our medical stuff, which 95% consists of VrayFastSSS2 materials, have increased 4-5 times and we´re actually in trouble going through iterations and meeting deadlines with our small farm.
And this is only because prepass mode has been deprecated.
I still don´t get it, because we only loose and gain nothin. The quality improvement you might get with actual skin might be nice, but for our stuff its not noticable.
On top of that, we have to redo all our materials and replace vraydisplacement with inferior bump mappings, or our rendertimes would be even higher.
So....
Can you PLEASE bring back prepass mode for VrayFastSSS2?

For the time being we could still install a parallel version of 3ds max 2020 and just keep using our 3.7 Vray licenses to render the medical stuff.
But thats obviously really not ideal and would lead to a bunch of other issues and confusion.

Maybe you can just make a downloadable VrayFasFastSSS shader for the folks like us, that JUST has the prepass mode, if you don´t wanna ship it anymore, so we don´t loose money because of the uprade...

[matanov]

Unfortunately, we are blocked from bringing back the prepass mode by the changes in V-Ray core. All new general improvements like lights adaptivity and other core changes are incompatible with things like prepasses. So even if we prepare a special build for you, there is no guarantee that the renders won't be full of artifacts and other raytracing issues.

Have you tried using a denoiser? There are 3 different denoising engines available in V-Ray 5 and there is also a standalone tool that can blend between frames for smoother denoised animations.

[ben_hamburg]

Well, that sucks for us then...
We´re already using denoiser with a base noise of 0.1. Going any higher doesn´t produce great results.

Stupid question...but could we still install max 2020 and Vray 3.7 and run that parallel in our farm then?
Until we figure out something better, this would be our best option then for the sss stuff...

[ben_hamburg]

Well, looks like deadline supports parallel versions, so I guess its possible.
Thats what we´re going to have to do then, the rendertimes are ridiculous.
S scene that rendered in 2-5 mins. per frame WITH vraydisplacement now renders at up almost 2 hours WITHOUT vraydisplacement.
So we actually loose image quality and with a render times increase up to 24 times...

Rendertimes on "normal" stuff is fine, in most cases better, but full screen multimaterial sss is just bad.
First time in years I am thorroughly disappointed with Vray...

[matanov]

24 times really sounds bad. I know you provided a scene last time but can you send me this one?

[Oleg_Budeanu]

Well, looks like deadline supports parallel versions, so I guess its possible.
Thats what we´re going to have to do then, the rendertimes are ridiculous.
S scene that rendered in 2-5 mins. per frame WITH vraydisplacement now renders at up almost 2 hours WITHOUT vraydisplacement.
So we actually loose image quality and with a render times increase up to 24 times...

Rendertimes on "normal" stuff is fine, in most cases better, but full screen multimaterial sss is just bad.
First time in years I am thorroughly disappointed with Vray...

Can you provide at least a partial scene, maybe one object with that problem? I am really interested in investigating, too, because sometimes I've been asked if I can produce medical renderings, and I am concerned about that. If that's possible - would be really cool and helpful! Thanks!

[ben_hamburg]

Hey there,

So, after talking to support, I got a couple good tips about vraydisplacement, using GI to speed up rendering and adpative lights, which all helped to reduce rendertimes.
Since they couldn´t test with tyCache, I did some more tests at home and was very disappointed to see that rendering with the tyCache increased the rendertimes by a lot again.
Glad to say though, that I found out at least why: When switching from "Vrayinstances" to "Meshes" in the tyCache render tab, rendertimes went back to normal again!
It seems counterintuitive, that meshes would render faster than Vrayinstances, if thats not intentional, it might be worth looking into!

[eimear_carroll]

Hello,

We have the same problem with the Fast skin material doing medical animation, its only raytraced now and its very slow compared to the prepass mode.

I see you have added in Vray 5 the AlSurfaceMtl but it is still slow to render. Looks great, but it is too expensive in time. Why did you deprecated the Prepass mode? and if you dont want to revert it, would it be possible that you provide training on optimizing the new materials to get the same look like the prepass setup and more important render times that we had before?

[ben_hamburg]

Thanks! I knew we couldn´t be the only ones...
Rndertimes are still too high for us, we can afford 2-8 mins per frame for these animations and we are at least twice as slow with raytraced materials.
Not much more optimization to be done there. so we simply reverted back to 3ds max 2020/Vray 3.7 and run that in parallel now. So all medical animations we do with this and use max 2022/vray5 for everything else.
Not ideal, but the best we can do at the moment.