Just a fast feedback for vray gpu 5

[luisgamino2]

Hi Konstantin and Peter Chauchev


I AM rendering some heavy scenes and i can do My renders with a high Quality there is just 2 things that i have found while i was doing some renders

1. Vray gpu with RTX takes too much vram to render a tapestry with vray fur, Even with level on detail on it takes a Lot of vram, with cuda this doesnt happend it renders fine and it doesnt take too much memory i don't know why this happens with RTX, imposible to render with RTX vray fur since it takes a Lot of vram and vray gpu crash

2. Environment fog is an amazing effect and it doesnt takes more memory so i would like to use it since this happens in real life and gives a better look to renders, since in real life there is always an environment fog in exterior Even with sun this happens. But is really slow with vray gpu, with scatter on and off it takes too much time, it is a Nice effect which i would like to use but... Is very very slow, i understand this is a real effect and that is why it takes too much time, but believe me is really slow.

I don't know what else vray gpu team can do to make this effect faster than before.

RTX with vray fur and environment fog needs a real look to resolve this issues


Thanks

[Muhammed_Hamed]

Hi luisgamino2 I hope you are well,

Vray gpu with RTX takes too much vram to render a tapestry with vray fur

We are aware of this behavior, Cuda mode uses less memory than RTX. I have this on the GPU roadmap, the developers will take a look soon
This is not a big issue at the moment as Cuda mode is as fast as RTX in most cases, you can safely use Cuda mode for your scenes
You can stick to progressive mode for rendering, it is efficient on using GPU memory. We have some memory optimizations coming up in V6 like texture compression.

But is really slow with vray gpu, with scatter on and off it takes too much time, it is a Nice effect which i would like to use but

Fog shouldn't use a lot of memory, this is not expected to happen
Fog is indeed slower to render, what I do usually is use a higher noise threshold and rely on denoising. You will find that denoising is very effective with fog usually, you will get away with using noise threshold like .02 or higher(to have a faster render),
On using fog the noise is just more uniform and easy to remove with denoising
in V6 rendering fog is faster with the standard V-Ray renderer, I will ask if this improvement comes to V-Ray GPU
On another note, I do like the fog effect and I use it in all my renders as well

Have a great day!

Best,
Muhammed

[luisgamino2]

Hi Muhhamed

Well RTX is always faster than cuda almost in everything, interiors, exteriores, rendering some trees and plants, vray hair material a long with vray fur is always faster than cuda.

This needs to be adressed since RTX is always faster and Also vray gpu renders very fast on exteriors but takes hours to render an interior space.

About environment fog i probably wrote Bad it doesnt take more memory it just fine about that is the same vram amount with it or with out environment fog.

Really believe Muhhamed is a great tool but is very slow, i don't use this kind of treshold .02 is too much noise, i always use high settings like .01 on final noise.

Also environment fog looks really Nice but with a really low treshold like .0075 or at least .01

Environment fog with .02 or .03 on noise looks really bad and the denoiser for vray gpu doesnt work really well. You loose a Lot of details!!! Even on default or mild set. Even selecting on glass material affects all Channel on vray material.

As i told before this needs too to be adressed it was a Big update on vray next on gpu but it is really slow.

Nothing has changed in years about that.

That why i'm writing since a new major versión is coming in the next few months.

There are a lot of issues that needs to be adressed before You bring new features and don't left things a part. Like issues or things at a half.

Also the blur setting in the vray material sometimes can be helpfull if You have a very crisp bitmap You can give a little bit of blur to make the bitmap more confortable to see, but blur on materials doesnt work on vray gpu.

For example the bitmaps for displacement in a stone wall.
Very usefull here!!!

I Know vray team are busy with the release of vray 6 for 3d max... But i'm writing before the release of vray 6 beta for sketchup so You can check what kind of problems do we have with vray 5.1 and vray 5.2



Thanks again
Best regards Luis Gamino

[Muhammed_Hamed]

Thanks for the feedback as always Luis,

I will see what can be done about fog rendering on GPU.
About RTX vs Cuda, they are usually close in performance except for scenes with a lot of grass or leaves, or hair. This is where RTX could be faster
But generally speaking Cuda mode has been improved on speed and caught up.

Have a great weekend

Best,
Muhammed

[andrei_lazar]

I've spotted the same problem with memory usage on RTX the only way to overcome this was to use the Texture resize function to reduce the texture to a lower value this way i could render with RTX normaly. For example(depends on scene) i can use a maximum 5k texture resize on CUDA, whereas 2048 is necessary on RTX. It you run out of memory renders go very slow.

Muhammed_Hamed Is there a way to flush the GPU memory after render? I had some instances where i needed to exit 3dsmax and open it again in order for the GPU to render at full power as it seemed sluggish. A 50sec frame would take 6 min and after a quick restart it got back to normal

[luisgamino2]

Hi Andrei_lazar

Is not only the vram i have found a Lot of issues with vray gpu, yesterday i was rendering a Big scene with a Big wall of 2d displaccement for a stone wall, i just increased the texture resolution from 256 to 500 or 1000 not that much, this gaves me a Lot of issues, vray gpu didnt render i was so worry for My gpu, why one gpu didnt work??? It was the texture resolution You have to left by default with 256 to avoid issues.

With vray cpu You can increase that parámeter with out issues there is no issues with vray if i increase that parámeter but with vray gpu You have to be very cleaver... Sometimes i suffer with vray gpu and sometimes i enjoy vray gpu...this is not normal is like a lottery with vray gpu... One Nice day, in another day a bad day with vray gpu

for small scenes works really Nice, but when You begin to use vray fur or vray displacement or 2d displaccement then vray gpu suffers.

But seems that all vray gpu users suffers sometimes with vray gpu.

Vray cpu on the other hand is very Stable and works everything out of the box with no issues.

[Muhammed_Hamed]

Muhammed_Hamed Is there a way to flush the GPU memory after render? I had some instances where i needed to exit 3dsmax and open it again in order for the GPU to render at full power as it seemed sluggish. A 50sec frame would take 6 min and after a quick restart it got back to normal

Hey andrei_lazar , thanks for the report!
I'm investigating this now, it is correct that V-Ray doesn't release GPU memory until you exist 3Ds Max

I will report back with more information soon

About GPU memory management, this should be improved in V6, it is high priority to us. We have texture compression working internally, it helps with complex scenes.

Best,
Muhammed

[Muhammed_Hamed]

luisgamino2 We need a scene for the displacement issue. Being able to reproduce on our side, I will make sure this gets fixed
I'm testing with 5.2 now, displacement is working fine. This is something specific to your scene

Best,
Muhammed

[luisgamino2]

Hi Muhhamed

I could render the complete proyect with RTX in bucket mode, that worked fine for me. Cuda with progressive mode didnt work i don't know why.

But i have found that if You increase the resolution up to 500 or 750 or Even 1000 vray gpu doesn't work really well.

Vray gpu suffers when You increase that parámeter "the resolution"

It says the max... Is 1000 millions... That information is not correct... So i choose 1000 for My 2d displacement thinking it was fine... It was too high with vray gpu that is why i found a very unstable moment with vray gpu.


So it should Say be carefull with this parámeter if You are using vray gpu, something like leave it by default or at least increase to 500 so You won't get an error.

with vray cpu You can go further with these settings but with vray gpu is different... Sometimes i wonder when i'm going to find another error with vray gpu or another unstable moment.

Thanks for your help Muhhamed, i prefer keeping My scenes by My own since i work sometimes years on that scenes.

But we can have later a team viewer if You want to check what happened.

For me it is fine right now... Thank god we have cuda and RTX.

If cuda doesnt work, well RTX works... 2 kind of solutions for every moment with vray gpu.

What sometimes makes me angry is when i found an unstable moment with vray gpu and i have to spend time where is the error and how can i fix it... When it should work out of the box for heavy or small scenes.

The other day when i was rendering a church proyect... Vray gpu didnt render with RTX but rendered perfectly fine with cuda mode. That was for the vray fur, with RTX takes a Lot of vram but with cuda it doesnt take too much memory is fine with cuda.

Other than that... Vray gpu is fantastic!!! Is just sometimes scary me when something weird happens

Thanks
Best regards Luis Gamino

[Muhammed_Hamed]

Thanks for the feedback as always luisgamino2

We are aware displacement works differently between V-Ray and V-Ray GPU, it is something that we will look at some point. Generally speaking stick with the default values for GPU displacement, and use it reasonably to avoid memory limitations

I can arrange a Team Viewer setup, keep in mind we need to be able to reproduce an issue on our side in order to fix it
I'm glad you are able to render your scene now, although if you send it to us we will investigate and solve this behavior so you don't run into it again

For now I still recommend Cuda mode and progressive rendering, it is the most efficient setup on using GPU memory

Best,
Muhammed