handle heavy scenes causing high ram usage (automotive)

[arqrenderz]

+1

[Rhodesy]

I think C4D also keeps a copy of the scene in RAM too which sucks. I used to use a trick with Vray a few years ago where you just close your scene once the render had started and you could save some RAM but you had to be careful with IES lights. But from what I have learnt about Corona is that it continually still has to sample all the C4D native shaders that are being used in the scene. So Im guessing if I close the scene in the background they will not be read anymore?

Either way I find my 64GB soon fills up on highish res scenes with lots of layers which can be a real pain as it always happens when you are nearing the end of the scene creation and just want to hit render and leave.

[Frood]

doubles the memory usage by storing the entire evaluated scene and retaining it during and after rendering.

Regarding memory usage and evaluated scene:

This one puzzles me since the day it poped up: https://corona-renderer.com/bugs/view.php?id=1947
Unfortunately there is no conclusion (at least on mantis). It has always been my understanding that the renderer gets a evaluated scene for a given frame/tick only - at least for simple geometry without any animation.

However rendering that scene as is and after collapsing everything to stack result leads to ~40GB vs. ~10GB(!) max working set.

It seems that the complete stack history is passed to the renderer (?). This means if we have trouble rendering complex/large scenes there could be a one-button "solution" (destructive) named "Collapse" from the Utility panel? Isn´t this something that should happen anyway when the scene gets evaluated?


Good Luck

[Ondra]

I can only speak for Corona, but Corona does not request nor gets nor stores anything with history - we get flattened triangle mesh after all modifiers, end of story. It is however possible 3dsmax stores something extra when we request this. Quick hunch: erasing undo history might help?

[Frood]

Well... no. The scene from issue #1947 is a very good example:

1. Restart max, open it, render it: 40 Gigs.
2. Open it, collapse stacks, save it, restart max, open it, render it: 10 Gigs ram...

And with "history" I was just refering to some existing modifier stack, not to the undo history.

Good Luck

[Charlie Nicols]

I posted here about this, https://forum.corona-renderer.com/index.php/topic,6176.0.html . See for test results.

[Frood]

Yes I´ve seen this but there is nothing unusual with your tests imho (including max staying at high ram usage after a render). I´ve done something similar for v1.4 and while it´s all expected, you have to be aware of what happens if you activate adaptivity/denoising. Doesn´t mean that there is no room for improvement though. Afaik there are some ideas in the drawers to lower cVFB memory consumption generally.

But the problem with the mentioned scene above is about just geometry with collapsed stack vs. geometry with some modifiers in the stack. Black Max magic maybe.


Good Luck

[Charlie Nicols]

Yes I´ve seen this but there is nothing unusual with your tests imho (including max staying at high ram usage after a render).

So you are telling me for one of the most basic scenes you can make in 3DS MAX combined with Architectural Visualisation production ready render settings I am going to struggle with corona and machine with 32GB worth of RAM?

[Frood]

I´m telling you another thing: You are not alone :) You can waste every ram on earth with high resolutions and additional passes. I can easily fill my 64GB box rendering a Max teapot with 4 segments.

But as mentioned, VFB memory allocation is another story.


Good Luck

[Juraj]

You are not alone :) I can easily fill my 64GB box rendering a Max teapot with 4 segments.

:- )

I am not sure if this is more of pub bragging ( "that is nothing, I can do....") or alcoholics anonymous meetup ( "I too waste my ram easily" ) but it cracked me up.

But yeah, 64 is the new 8.

[Ondra]

I can fill it with 3 lines of C++. 2 if I break our coding conventions :D

[Christa Noel]

 I can fill and break any ram in this universe with half of boiling teapot :D

[FrostKiwi]

I can fill it with 3 lines of C++. 2 if I break our coding conventions :D

With April 1st coming up, please implement this to show up once every year.

[pokoy]

Love it, good one!

[Christa Noel]

Nice idea! Haha