Big vrscene temp file and huge RAM usage

[fasterG]

Hi,

I'm trying to render out a scene with 12 cartoon characters and some chairs. Everything is referenced so main mb file is small and nice.
My problem is that I can only batch render 4 frames at a time. The temp vrscene file is then 8GB, and the RAM on main station is quickly reaching 95% (total of 64GB).
More frames lead to 99% RAM usage and after that things go south.

First I planned to render the characters 3 or 4 at a time, but there is not enough time in this project.
So I need to learn from this. What solutions are there?
Is there a way to limit max RAM usage and still be able to render the scene?
This huge vrscene temp file, is it because of the references? I use distributed rendering.

Im on Maya 2018.4 and Vray 3.6.

Thanx.

[Morbid Angel]

Hey fasterG, can you explain a bit about the vrscene? are you rendering out of maya or you are using standalone? In theory if you use mayabatch you don't need to write multiple frames to a single vrscene file. If you need help rendering this project send me an email: silhouetteimages@gmail.com I have a farm and I will help you out.

[fasterG]

Hi,
Oh that's very helpful
The main scene file is an ordinary .mb. The vrscene is the one that's created in Local -> Temp.
Yes I batch render from inside Maya. DR using a couple of extra nodes. It takes about 20 min for the scene to start render, then the individual frames is around 4 mins.
So the real bottleneck is the constant start and stop (and deleting the temp vrscene file in Local->Temp every 4 frames..).

I think I just have to babysit the computers all day so I have some images to work with tomorrow.

[Morbid Angel]

are the characters complex? do they have fur on them? it could explain why this is that slow. Or perhaps displacement?

[fasterG]

Ok, that may explain things..
They don't look very complex, but they have different modes built-in, hair and dress wise. Even if I use poly mode for the hair now (instead of nHair / xGen) it could still bog down the computation?
I don't think fur is involved. Maybe displacement somewhere, not really sure tbh since I bought the rigs.

[Morbid Angel]

it would be a guess but the hair has a render time tessellation which is if too high will result in a very dense hear subdivision and so will require a lot of ram, its probably where the issue would be.

[fasterG]

I have another go at my character with xgen hair. It sure looks nice but almost unrenderable

Yesterday I made a test scene where I posed the character in a room (no char anim). IPR worked fine and single frame render was quick and snappy. So I animated a camera and started a batch render of 150 frames (distributed to a couple of render nodes). After 55 minutes the render started!
55 minutes to prepare the scene for rendering. In User->AppData->Local->Temp a vrscene was slowly growing to around 10GB before the render started. Why?

I don't know much about xgen but it seems strange? Especially with a static pose. When I switch to simple poly modeled hair the render starts in a couple of minutes so its obviously something with xgen.
Any suggestions how to cut the start up time?
(Along with the scene file, .mb, there are automatically .xgen and .abc files generated. Is there a way to freeze/bake the hair for static scenes?)