Chaos Corona Forum

Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: DanyA48 on 2018-02-05, 21:37:49

Title: Render take huge time !!
Post by: DanyA48 on 2018-02-05, 21:37:49
Hi !!

I have a big problème with my scene.
I'm modeling an house, so i allready done bedroom, living room and kitchen.

Now i'm trying to render differents views from cameras.
To tchek luminosity i hide all elements and try to render in 640x480 but after 10min Corona still calculate illumination ! I mean render screen stay black (except four-five white small points).

I allready done some renders before and i never get this probleme.

So there are my questions :
- if i hide all objets before render, corona calculates them even if they are hide ?
- how can I do to only calculate objects in my camera field ?

Regards !!
Title: Re: Render take huge time !!
Post by: romullus on 2018-02-05, 22:11:09
What do you mean by saying that you've hide all ellements? Maybe you've accidentally hide the lights and there's nothing to emit light in your scene?
Title: Re: Render take huge time !!
Post by: DanyA48 on 2018-02-05, 22:41:18
Hi Romullus

I mean in layers panel i closed "eyes".
Necessary lights are not close (i use sun and  HDRI)
Title: Re: Render take huge time !!
Post by: sprayer on 2018-02-05, 23:05:29
Just check what current task in rendering dialog, to be check if it's rendering or making preparation for rendering. And check you ram usage, is it enough for your scene? And double check light =)
Title: Re: Render take huge time !!
Post by: DanyA48 on 2018-02-05, 23:47:06
Just check what current task in rendering dialog, to be check if it's rendering or making preparation for rendering. And check you ram usage, is it enough for your scene? And double check light =)

"Current Task : Préparing geometry"
Préparing displacement + geometry take 20min.... to render a kitchen 1280*900. The task is still in progress... :-/

About light
I only have sun and HDRI. Nothinl else.
Title: Re: Render take huge time !!
Post by: sprayer on 2018-02-06, 09:48:26
Check this settings http://imagizer.imageshack.com/img922/8161/0AbCfn.jpg try to set higher or remove displacement material for test
Title: Re: Render take huge time !!
Post by: romullus on 2018-02-06, 10:44:04
Do you get warning about low RAM? It wouldn't hurt to attach screenshot of VFB with stats tab visible.
Title: Re: Render take huge time !!
Post by: maru on 2018-02-06, 12:22:03
What resolution are you rendering at?
It's probably displacement calculation being too detailed, and you may be running out of RAM.

More info: https://coronarenderer.freshdesk.com/support/solutions/articles/12000023310
Title: Re: Render take huge time !!
Post by: DanyA48 on 2018-02-06, 12:27:24
Check this settings http://imagizer.imageshack.com/img922/8161/0AbCfn.jpg try to set higher or remove displacement material for test

Hi Spray. Thank you for your contribution.
I found the problem : I removed all displacement maps on basic wall texture.
And Screen Size was set on "1"

On my laptope (currently im working on my laptop waiting for my work station back) i have a warning message about RAM. But as i said in my post I allready done all previous render with these warning messages.

Anyway now, without Displacement map on the wall i can make render (8h for 1280*900...a kitchen viz ... I know it's creasy but usual with this laptop ah ah !! )
Title: Re: Render take huge time !!
Post by: DanyA48 on 2018-02-06, 12:33:16
What resolution are you rendering at?
It's probably displacement calculation being too detailed, and you may be running out of RAM.

More info: https://coronarenderer.freshdesk.com/support/solutions/articles/12000023310

Thank you Maru. Appreciate !

That was the problem. My basic wall material had displacement map. Evenif i only rendered the kitchen, my house wall with displacement was calculated.
I removed displacement map on wall texture and now it's ok !
Title: Re: Render take huge time !!
Post by: DanyA48 on 2018-02-06, 12:36:20
So depending computer it's better to incrase Bump parameter intead low "Screen Size" in Displacement setting ?
Title: Re: Render take huge time !!
Post by: maru on 2018-02-06, 13:43:58
So depending computer it's better to incrase Bump parameter intead low "Screen Size" in Displacement setting ?
It's best to use bump for small, fine details, and displacement for large features only.
Think of a brick wall:
Bump - cracks, scratches, surface structure
Displacement - brick pattern
Title: Re: Render take huge time !!
Post by: DanyA48 on 2018-02-06, 15:25:55
So depending computer it's better to incrase Bump parameter intead low "Screen Size" in Displacement setting ?
It's best to use bump for small, fine details, and displacement for large features only.
Think of a brick wall:
Bump - cracks, scratches, surface structure
Displacement - brick pattern

Thank you !!
I got it !
Title: Re: Render take huge time !!
Post by: Njen on 2018-02-08, 19:35:07
And when using displacement, rarely do you ever need to go below a screen size of '1', as lower values are essentially creating edge lengths of tessellated geometry that are smaller than a pixel, which is mostly unnecessary.
Title: Re: Render take huge time !!
Post by: DanyA48 on 2018-02-09, 06:55:33
And when using displacement, rarely do you ever need to go below a screen size of '1', as lower values are essentially creating edge lengths of tessellated geometry that are smaller than a pixel, which is mostly unnecessary.

Ok, thank you Njen !!
Title: Re: Render take huge time !!
Post by: benzodm on 2018-03-20, 02:25:50
Hello everyone, I need help with slow rendering too. I need to render a huge image for the poster, so resolution set to 5906x4724 and rendering is very slow for some reason, also CPU is not loaded at all. I've searched some info about low thread priority, but there is no option like that in Corona 1.5. I used to render the same scene couple of months ago in 2000x1500, and it took me 1-2 hours for 50-60 passes, CPU was loaded with 70% and more, and now it's only 5-10%. Any solution for this?  Also, i've set 3dsmax.exe to real-time priority

AMD Ryzen 5 1600
16gb RAM 2400
3ds max 2016, Corona 1.5
Title: Re: Render take huge time !!
Post by: Njen on 2018-03-20, 13:03:48
16gb of RAM is not much, sounds like Corona might be hitting your HDD swap disk.
Title: Re: Render take huge time !!
Post by: TomG on 2018-03-20, 13:15:20
Sounds very much like memory, especially when changing resolution changes the render speed from what would be expected.

This article covers most of the causes / solutions, e.g. LightSelect render elements each need more memory, so higher resolutions with lots of those can require a lot of memory (reducing the LightSelect layers, or even backing LightMix to scene and removing the layers, can help). https://coronarenderer.freshdesk.com/support/solutions/articles/12000023310-i-am-getting-a-sudden-rise-in-ram-usage- (https://coronarenderer.freshdesk.com/support/solutions/articles/12000023310-i-am-getting-a-sudden-rise-in-ram-usage-)