Out of Ram -64gb Machine?

[Charlie Nicols]

So, we are running into this problem where we get the following message,

System is running low on RAM. You may experience excessive parsing times and/or crashes.
You will probably have to simplify the scene.

Our workstations have 64gb of ram.

I am using 3 Xrefs that total 1.65gb - Yes it's large but it needs to be!

This only seems to happen when rendering for a long amount of time. The Ram slowly gets eaten up.

We have denoising turned on.

Scene Stats;

Polys - 34.7M
Lights- 28 - Grouped
No Proxy as of yet - Don't think they would help the ram situation?

Interactive Light Mix Turned On

Multiple elements rendering - total around 13

Render size 6000*6000*

Rendering for a VR - Using the Corona Camera Mod.

**also like to note the base ram usage is 4gb and 8.8 with max +scene open.

[Ondra]

How many render elements do you use (including lightmix)?

[Charlie Nicols]

13

[Ondra]

ok, if all of them are denoised, then this can actually take up to about 30GB RAM. That could be it. We will add memory usage statistics to the low memory message in next build

[LUKEC3D]

Hi, if can help, we work on scene 20/ 30 x biggest with billion of polig with 4 / 5 xref and with 64 gb ram work good. Only we use LIght mix to find good light, and then re-setup light with new parameters and render with 5 / 6 Render elements, but wthout light mix, and all work good. Use denoising and render on 7000 pixel .
Bye
LukeC3D

[totinguis]

Hi, I have been having this issue as well with very complex scenes with denoise, but no light mix and with around 6 render elements including masks. Scenes with 30 million polys and up this warning pops up and sometimes renders ok, sometimes renders extremely slow and sometimes crashes max. This seem normal to me on huge scenes, but what really makes me scratch my head is that I'm having this issue with a really simple interior scene with around 6 million polys. When ever I hit render on res higher than 3k this warning pops up and sometimes max crashes. Inbetween I randomly get normal to extremely slow render times.
Scene geometry is OK and modelled from scratch, no client model whatsoever, biggest textures are 4096x4096 and my workstation have 32gb 2400mhz ddr3

[Charlie Nicols]

ok, if all of them are denoised, then this can actually take up to about 30GB RAM. That could be it. We will add memory usage statistics to the low memory message in next build

This is great news. We can't have this problem as not all our workstations are 64gb so finding out where we can make cuts will help.

[maru]

Are you by any chance using displacement in your scene?

Here are some additional tips on optimizing RAM usage:
https://coronarenderer.freshdesk.com/support/solutions/articles/12000023310
https://coronarenderer.freshdesk.com/support/solutions/articles/5000534930
https://coronarenderer.freshdesk.com/support/solutions/articles/5000675854

[Charlie Nicols]

Thanks for those articles, I had read them. The scene has no displacement and has now been optimized further.

As an update to this after keeping a close eye on a 150 pass - 7 hour render on one of our 32 gb machines I can confirm the RAM issues we have been having are happening at the Denoising phase.

The render sat between 21-23 gb of ram usage until the Denoising phase started. At this point the ram usage shot up to 32gb and paged.

At the end of the Denoising phase the machine dropped to 19gb until render end.

The render was being distributed to 4 other machines via backburner.