Have you tried V-Ray (RT) GPU ?

[vlado]

as soon as I open up that scene again, there is no way to set Vray Adv. as the renderer. I'm stuck with RT without settings and with no way to change frame buffer size.

It would be useful to get us that scene to support@chaosgroup.com so that we can figure out what's wrong. All these things work fine here but there may be something specific in your case.

Best regards,
Vlado

[kosso_olli]

And it has many features that RedShift doesn't, does not clamp all the shading, thus looks better and with 3.5 and later is much faster on many of the scenes ...


Best,
Blago.

Is this statement based on 1:1 comparisons you do internally? If so, can you share the results?

[Undersky]

Are the reasons for you to think that already mentioned in the threads (i.e. are all of your troubles already mentioned here, I want to be sure that we can gather as much feedback as possible).
Like, is it that bug that you mention and the fact that it doesn't support everything from Adv and it doesn't match it looks? This is important, because no GPU raytracer is currently comparable with the feature set of V-Ray Adv, and V-Ray GPU from all GPU raytracers is by far the closest you can get.
And it has many features that RedShift doesn't, does not clamp all the shading, thus looks better and with 3.5 and later is much faster on many of the scenes ...


Best,
Blago.

Well, I must say that my knowledge of RT is rather limited, due to the fact that there are always some reasons that I stop using it. And that's sort of my point with my comment about Redshift... I don't mean any disrespect or anything, but the stability, the speed, the features in Redshift are just ahead of RT, and given that RT has existed longer than Redshift, they must be doing something right, whereas RT seem to be stomping in the same place.

I had hopes that the hybrid rendering would bring it up to par with Redshift, speed wise, but sadly, that wasn't the case.

But I also understand that they have different purposes... RT, as far as I understand it, is more of a preview renderer, with the potential to use it as final frame renderer as long as it doesn't crash. The equivalence to that would be Redshift's Progressive mode, which is intended for preview only (thus making it slower for final frames). So I haven't compared progressive vs. progressive, but I'm more interested in final frame result / time. I.E Vray RT vs. Redshift in bucket mode. It may not be a fair comparison, but one that makes sense in my line of work.

It would be useful to get us that scene to support@chaosgroup.com so that we can figure out what's wrong. All these things work fine here but there may be something specific in your case.

Best regards,
Vlado

I managed to reproduce the bug and have sent a zip to the support. The image attached to this post shows the difference in settings after the bug has kicked in. It seems that what's triggering it is launching IPR via the Play button in the frame buffer, then resizing the window (forcing RT to change render resolution) and then after a while the settings gets messed up and the only way to get back to Vray Adv. is to merge everything into a new scene.

[vlado]

I managed to reproduce the bug and have sent a zip to the support.

Thanks!

Best regards,
Vlado

[savage309]

Thanks!
This feedback is actually very helpful.

I don't mean any disrespect or anything, but the stability, the speed, the features in Redshift are just ahead of RT, and given that RT has existed longer than Redshift, they must be doing something right, whereas RT seem to be stomping in the same place.

I just wanted to say that we have added interactive gpu accelerated denoising, raytraced sss, directionality for rect lights, stochastic flakes, clipper, algorithm that allows rendering of practicaly infinetely many lights without slowdown (something that only V-Ray and V-Ray GPU has in general) that removes the need of "light samples" options and so many other options to tune, optimized perfromance for layered materials, added support for forest pro forest color texture, correct GGX(GTR), light select that has all GI in it (even with cached gi), disc light, adaptive progressive image sampler, nvlink, hybrid rendering, more than 16 bounces, much less gpu memory usage for reserved system memory, mdl textures and materials, glsl textures ... this is just part of the features that we have added in the last year or two, that actually Redshift doesn't have.

I can go on with all the features (old and new), but I think you get the idea (and it will be rather huge list). Nevertheles, such feedback is very much welcomed and it will help us try to message our users better in the future.

But I also understand that they have different purposes... RT, as far as I understand it, is more of a preview renderer, with the potential to use it as final frame renderer as long as it doesn't crash.

Well, I must say that my knowledge of RT is rather limited, due to the fact that there are always some reasons that I stop using it.

If you have samples for problems - slow rendering, crashes or whatever else, it makes it times more easier for us if you send those over so we can check, and fix them.

I know it is time consuming and I am really thankful to all the people that invest their time in such reports.

Best,
Blago.

p.s. you can't use Adv in Active Shade. This has been always the case. If you turn to Production Render, the Adv will be there again. Also if you use V-Ray GPU after you have used Redshift it will crash. That is because they allocate all the gpu memory (even for empty scene) and they never release it, even after you change the render. If you can ask the guys to fix that, it will be helpful.

[BBB3]

One thing mentioned here that would be useful is to retain access to the IPR settings when switching to RT as a production renderer. Right now, if I'm not mistaken, the only way to change the IPR settings (eg. from dynamic to fixed res) is to go back to V-Ray Adv and change renderer again to RT, by which time all your RT settings would have reset to default.

[thanulee]

I had issues btw, when pressing IPR button while i was on active shade one two times i tried it (after seeing it in a tutorial).
Pc started lagging a lot and i was confused i thought i enabled cpu same time or something and eventually it crashed or i restarted to fix this, cant quite recall.
IPR is working only on cpu right? thanks

[anthonyh]

I don`t use RT because of reading about the disparity between RT and ADV and also because my quadro 4000 is pretty long in the tooth so it offers me no advantage. We`re primarily animation with a small render farm, so backburner frame render or DR for some stills is what we use. Probably stuck in the past because of hardware a bit but it works for now, until we can afford to just throw multiple Titan-X cards into some new uber pcs with no care for the cost. The issue with this is that`s ok for one or 2 pcs but not for a farm, we ain`t made o` money. Played a bit with IPR and it`s promising but again slow on our machines. Can`t use it because vray 3.5/3.6 have enough issues we just can`t use either yet in production.

[biochemical_animations]

Hey folks,

Just wanted to check how many of you have tried V-Ray (RT) GPU in V-Ray 3.5 or later?
If so, what hardware have you used, do you have dedicated GPU for monitor and has it worked for you in general?

If not - why? Was it startup time, render speed, UI, lack of features, interactivity, stability or something else?

Thanks,
Best,
Blago.

Just saw this thread...

my animation workflow totally relies on rt gpu 3.6 hybrid and the stand alone denoiser.

my hardware is outlined in my ghetto build thread, but I have 3 monitors, each plugged into separate gpus and it works great.

[LeePuznowski]

After about a year of extensive use of RT GPU for projects, I find the workflow solid (enough for production). The features are robust enough leaving little to be wanted (needed). This ranges from technical animations, character animations, product shots, production set design mock-ups, etc. My main gripe is simply the 3.6 update, which I'm hoping will be resolved soon, or maybe a nightly?

[kosso_olli]

I wonder what the purpose of RT in CPU mode is these days. I mean, we have IPR for this now, and it doesn't have any disadvantages. At least on my side. And as far as I know, you can even use the GPU for IPR, when you set the production renderer to RT and choose Cuda as the engine. Is this confirmed?

[vlado]

I wonder what the purpose of RT in CPU mode is these days.

It will probably go away.

Best regards,
Vlado

[biochemical_animations]

It will probably go away.

Best regards,
Vlado

I never use it...just use gpu.

[padre.ayuso]

I have always wanted to move onto GPU, but having a render farm with 5 machines that can render my scenes within 10 to 20 minutes (at 4K resolution) with hundreds of lights and millions of polys it has postponed my move until I find it faster to use GPU than to use CPU. Also, I do use GPU when lighting my scene as in the Active Shade.

I tried rendering a scene in GPU the other day (on 3.6) and it was taking hours to clean up at 4K. I sent it through my farm and it rendered within 30 minutes, if not less. Perhaps, as said earlier on this thread, it has to be marketed better.

I used Two Titan X (Maxwell technology) to render the aforementioned scene.

Best
Alex

[Alex_M]

I've used RT on a very small number of commercial jobs since Vray 3.5 but when I did it help me quite a lot. My hardware - 1 x GTX 1080ti 11 GB + GTX 980 4GB (which also powers my 2 displays).
I decided to make some lists to make it easier to understand my impression on RT.

What I like (in order of importance):

1. It's REALLY fast! Compared to my current CPU that is. It's faster than Adv pretty much every time. It would be interesting to see if this speed difference will change in favor of Adv when I upgrade my 6-core 4930k to the 16-core Threadripper 1950x.
2. RT's IPR/active shade is A LOT faster than Adv IPR with my current hardware. Though there are also cases where Adv IPR is faster if I turn on Light Cache for secondary bounces. Maybe the addition of Light Cache in RT IPR/active shade can be considered in the future? I'm interested to see if Adv IPR will become on par with RT IPR speedwise when I upgrade to Threadripper 1950x.
3. RT now fits a lot more stuff into the GPU memory because of the optimizations in the last few updates. Outstanding work!
4. Easier to upgrade hardware in the future - you just stick a new graphics card into the motherboard and you're done. Takes just 5 min. A lot less work than installing a CPU and you don't really waste any space unlike PC towers and render nodes.

What I don't like and why I still don't rely on RT in more commercial jobs (in order of importance):

1. Feature disparity. Still in quite a few cases in my daily work RT doesn't support features that I need for the specific job. Because of this, I'm afraid or I simply refrain from using it in the first place. I find that a lot of my assets, already made for Adv in the 1st place, need to be reworked to look the same in RT. Unfortunately I rarely have the time to redo my assets just so they look as intended in RT. I know that RT and Adv will most likely never produce the same results but sometimes this breaks the deal for me.
2. My computer becomes really slow when I add my display GPU to the rendering. It would be great if Vray didn't use 100% of the resources of my display GPU. Maybe 90-95% so I can at least check my mails and browse the internet. I can't afford a 2nd dedicated GPU at the moment and quite a lot of users also don't have more than 1 dedicated for RT rendering.
3. The lights' directionality parameter doesn't work correctly. I've already reported this.
4. Noise clears slow in highly reflective or refractive objects like mirrors, chrome, windows etc. A lot of times the image is silky smooth, zero noise, except for a few places where there are reflective/refractive objects with a lot of noise that takes really long to clean. Maybe RT should balance the workload so that these hard places get equal amount of GPU power focused on them otherwise the image looks a bit funny - silky smooth everywhere except for a few places.
5. Light Cache is calculated quite a bit slower than Adv. Like 2-3 times slower. Fortunately RT makes up for this with its blazing render speeds but still...
6. Larger scenes are somewhat slow to load into the GPU before rendering starts. Though I think I've noticed that subsequent renders start faster (don't quote me on that). Maybe unavoidable with GPU renderers because data transfer to the GPU RAM is slower than the CPU RAM? Improvements to this will be really welcome.
7. Setting up the lighting setup with RT IPR is a bit unintuitive since it always looks darker in IPR than final rendering with BF+LC.
8. IPR/active shade starts rendering from scratch when zooming in VFB. I've already reported it here.
9. Override depth in Global switches rollout doesn't work with RT so I can't raise the refl/refr depth on all materials quickly. Since all materials by default have a refl/refr depth of 5, they come out dark or black in my RT renders. I simply don't have the time to raise the reflection and refraction depths of every single material by hand. I think I've already reported this.
10. No support for Alpha contribution in Vray object properties.

Other thoughts:

1. Some defaults could be changed. For example RT could automatically detect which is the appropriate device to use. If the PC has Nvidia GPUs installed, it chooses the CUDA engine. If it has AMD GPUs installed, it enables the OpenCL engine. Also, Trace depth could be 15 or 20 by default. Newer users will be confused why their reflections and refractions don't look right or real enough. Just 5 traces is too low in my opinion.
2. Hybrid rendering (GPU+CPU) isn't faster for me in any type of scene and usage case. Moreover, half the time it's actually quite a bit slower than using just GPUs. Maybe my CPU is just too old, I'll test again with the 16-core Threadripper when I get one soon.

Wow, that was a long post. Sorry about that, I wanted to be as thorough and objective in my assessment as possible. Hopefully it doesn't give anyone big headaches. For me, RT is almost there. Just a few things and I will happily consider using it more and more without much (if any) hesitations.