Vray RT problem

V-Ray V-Ray for 3ds Max Issues
1

In active shade mode with this test scene works perfectly. When I try to render it gives me this and does nothing, just black screen. I try to use CUDA.

I am just using the latest nightly build.

More questions:

Should I enable SLI or disable while using cuda render?

How many gpu cards should I enable? The more the better?

Thanks.

2

Should I enable SLI or disable while using cuda render?
No, make sure SLI is off. V-Ray can use all the GPUs by itself (you can configure the GPUs that are going to be used with the tool named ocldeviceselect.exe that comes with the V-Ray installation) and SLI is not needed and can cause troubles.

How many gpu cards should I enable? The more the better?
Yes, just keep in mind that the GPU memory does not stack (2 GPUs with 2 gigs each equals 2 gigs of usable GPU memory for the rendering, not 4).

About the problem you have - there is a problem with the attachment, so I can’t see it, but in the latest nVidia drivers (ones after 344.16) Light Cache and SSS are broken and are causing crashes. In active shade Light Cache is disabled, so this may be the problem. We are already talking with nVidia for that issue and we hope that some of the next driver updates will fix it.

3

I think its 4 gigs, but its a 970 so its just 3,5 for some reason. Doesn’t matter. I always have the latest drive, now its 347.52 I dont know if that problem is still exist with that one.

4

Do you have any recommendation for when vray rt just doesn’t start with cuda? CPU render is fine, its going perfect even in vray rt, but when I try to use cuda render the vray render server administrator doesn’t pop up. When I start manually it says “there is another server already running”. It might be running but nothing happens, renders start going but blank screen, gpu cards don’t start. 3ds max re run not helping. Even activeshade does not start. Yesterday at least activeshade worked, and now.. nothing happens. Why? It seems completely arbitrary.

5

Can you make sure that you are not running V-Ray as a service ? Windows restricts the access to the GPUs of the services.

6

Then why is that even an option?:slight_smile:

7

However no. I dont think so. (Im not even sure what is that difference) I do what I always do. Start 3ds max, the dongle is in, start “Launch vray license server” then try to render stuff. Sometimes it works, yesterday activeshade worked with gpu like a charm. Today it doesn’t even start. With cpu there is no problem. I just dont know what am I doing differently today, that it does not start. Administrator window doesent pop up, now I got this.

If I set it back to CPU it renders fine.

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8

Can you double check this ? Please go to Windows Control panel > Admin. Tools > Services and look for VrayRTSpawner service

If it is there and running, please try to stop it and run a test with RT / GPU again.

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9

Hello Tashko

Thanks for replying.

I disabled vray as a service but it didnt help me much I’m afraid.

Then tested it, first I got this:

Then second and third try, for third try there was just a black screen, nothing happened the render kept calculating:

What do you reckon?

Thanks, Denes

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10

Thank you very much for the quick response.
Can you try to restart 3ds Max and on a new simple scene enable GI from the render settings and change both engines to Brute force / brute force then satrt RT/Cuda again.

11

With both set to brute force, it works.

Thanks!

Denes

12

Glad to hear that. OK then, I see that you are using driver version 347 where Light Cache and SSS are broken. You can revert back to an older driver version 344, for an example and you will be able to use LC for RT/GPU renderings.

13

Thanks, I hope Nvidia fixes it soon.

Denes

14

Latest 347.88 driver fixes the SSS2 and LC problems.

15

Cool, thanks:)