GPU Render fails on large scene : MemoryManagerGpu

[sean_brown]

Hello,

When my Maya scene gets to a certain size, the vray IPR and GPU rendering begins to fail. I get errors such as the one below. What does the error mean? Is this normal? Is there a scene size limit for GPU rendering? Are there tips to work around it?

Thanks

// Error: line 1: V-Ray : [MemoryManagerGpu::setupManagedMemoryInstance] 2: Could not allocate device buffer with size: 2451552 bytes
// Error: line 1: V-Ray : [MemoryManagerGpu::releaseUnmappedMemoryFromInstanc e] 2: Could not release device buffer

[nicolas_fuminier]

Hello sean_brown

It look like your GPU(s) VRAM can't handle your scene.
On an other word your scene is too big for your Videocard RAM.

There is a lot you can do to optimise your VRAM scene (textures, geometry, render setup) but first you have to be sure the issue come from your VRAM.

In the VRAY frame buffer you have tools to manage your VRAM consumption and also you can check your windows task manager (if you are on windows obviously)

See what happen when you try to render your scene in regard of your total amout of VRAM.
See also if you have more than one Videocard (on a single computer), it will take the lower amount of VRAM avaible on each card as a maximum avaible.

There is tons of advice we can add to this topic, but first you have to check.

Best,
Nicolas

[sean_brown]

Hello sean_brown

It look like your GPU(s) VRAM can't handle your scene.
On an other word your scene is too big for your Videocard RAM.

There is a lot you can do to optimise your VRAM scene (textures, geometry, render setup) but first you have to be sure the issue come from your VRAM.

In the VRAY frame buffer you have tools to manage your VRAM consumption and also you can check your windows task manager (if you are on windows obviously)

See what happen when you try to render your scene in regard of your total amout of VRAM.
See also if you have more than one Videocard (on a single computer), it will take the lower amount of VRAM avaible on each card as a maximum avaible.

There is tons of advice we can add to this topic, but first you have to check.

Best,
Nicolas

Hi Nicolas,

Thank you so much for helping me. Here is what I've found out.

First when I try to render with the GPU, the stats show nothing because it fails and gets cancelled. But here is what I see in the Log and the memory usage in Task Manager. I have 1080ti.



when i render with the CPU, these are the stats:

[nicolas_fuminier]

I'm not a expert with GPU crash, but I've seen some of them.

It's look like a VRAM issue to me (carefull I can totally be wrong). You haven't enought VRAM on your 1080 to fit your scene inside.
I guess you not that far to fit your scene into your VRAM but you miss a bit RAM.

As I can see before your crash you have a lot of Geometry (about 5.2 Gb).
Can you hide just some of them (not all of them) and see if it fit to your card ? It's not for the final render, it's just to see if everything is good on all the other possible issue.
Do you have Vray displacement on some object in your scene ? If yes can you try to desactivate it and test.
Can you reduce the polycount on some of your object without loosing to much quality ?
Do you have object in your scene hidden or not seen by your camera who can be hide ?
I guess with a 1080ti you are already rendering with CUDA and not with RTX (just to be sure) ?
You can also try to render without light cache and go straight forward with brute force, it would be much longer to render (and maybe a bit noisier) but it need less VRAM than light cache.

You can also check Muhammed_Hamed tips to optimize your VRAM issue (can't find the full post)
There is a short version : https://forums.chaos.com/forum/v-ray...ay-maya-2020-4

Or go check the Chaos page about VRAM optimization
https://support.chaos.com/hc/en-us/a...-GPU-rendering

Happy render,
Nicolas

[Muhammed_Hamed]

Well said nicolas_fuminier , thanks for your help

With the release of V6 the GPU documentation will get updated with information about saving GPU memory, from my posts here
Here is a link

Best,
Muhammed