large renders produce black frames, Mental Ray

[Spacelord]

Hi there,
I posted this on CGTALK and didn't get a response.
As you can see I'm trying to figure out how mental ray stores
frame buffers and why when I render using a crop rendering for splitting up large renders it works. But when I send a large render off to be split rendered over the network
I get the errors I talk about below.


Hi there,
I'm having issues rendering to strips (network rendering).
I'm trying to render a large image 10000x6900.
Its an interior shot using FG, Mr sky and Mr Sun.
All I get back is a black image with the mental ray tile outlines,
(those white corner things), no image just black.

http://img150.imageshack.us/img150/7429/blacktileswn2.png
Has anybody else seen this ?
I'm using 3dsmax9/mental ray, 2 gig of ram in each machine,
Windows 32bit.

cheers

I got it to work in the end, using satelite rendering.
I found out it was running out of disk space to save the frame buffer to.
I thought as long as there was plenty of swap space ( I had 3gigs set ),
but I figure out Mental Ray doesn't seem to use the system swap space.
Mental Ray uses its own and I only had 98meg free on the C: Drive.
So I cleared 3 gig off and it rendered using satelite rendering.
Strange though, that it wouldn't work rendering to strips (network rendering).
I'll have to check the other machines and see how much
hard drive space is available.

Does anyone have any info on storing frame buffers ?

[Spacelord]

Does anyone have any insight to rendering large frames in Mental Ray & 3dsmax9 ?
Is it best to have Gigs of Ram and 64bit windows ?
Has anyone test this ?
I've definitely found out that Mental Ray uses its own disk space for frame buffers and not the systems virtual memory/page file.

Whats the biggest render and complex scene people have rendered in Mental Ray ?

[Dodgeas3d]

I got this problem too... its becouse memmory limit, if image istoo big it simply crash memmory buffer, showing that black squares.
I managed to render like 6000x4000 with FG and SSS, but I used conserve memmory option and placeholder objects.

By the way u should use 3gig switch in windows it helps on some big renders, couse standart windows memmory management is limited 2 gig per program swap file and other 2 gig to kernel. So win 32 bit allowsonly 4 gig of max swap file. what gives 3gig switch is that it makes 3 gig for program and 1 gig to kernel memmory management.
You can find how to make that switch here http://technet.microsoft.com/en-us/library/e834e9c7-708c-43bf-b877-e14ae443ecbf.aspx

Another way is to use backburner for rendering single frame and enabling split scanlines, so renderer splits whole image 10kx10k to for example 5 images 2kx2k renders them and then combines. See max user reference for how to setup split scanlines. It helps render huge scenes not crashing MR.

I found that its all in frame size as if it gets over 2k and if scene is huge its allways problems showing up. try rendering as lower size strips as possible. Its bad taht strips support only horizontal splits, dunno why but if one side of render frame is big enought it couses crash for example u can easily render 1000x1000, but will get crashed rendering 1000x6000 or even 100x6000, becouse one side is too big.

Goodluck!

[Spacelord]

Hi Dogeas,
Thanks, My machines have had the 3gig switch for a while now.
It definitely makes a difference. I still get that error everynow and then. I also find split rendering has problems too.
Since the image is only split into strips and not split in to tiles causes problems. Since it still has to use the complete width of the image.
So if the image is 10,000px wide and only 150px high its sometimes still to large for Mental Ray.


Thanks for the reply

[oliviercefai]

I have just posted a new thread about this subject FYI

[Spacelord]

Hi Olivier,
Why start a new thread ?

cheers

[nisus]

Whats the biggest render and complex scene people have rendered in Mental Ray ?

Don't know, it's still rendering ;-))

nisus

[MasterZap]

A little bit of MaxScript perhaps?


rollout SplitRender "Split Render Tool" width:250 height:100
(
radiobuttons splitcount "Pieces to split render in:" labels:#("1", "4", "9", "16") default:2
spinner width "Total width:" type:#integer range:[0,32000,3000]
spinner height "Total height:" type:#integer range:[0,32000,2400]
spinner overlap "Pixel overlap:" type:#integer

checkbutton show "Show image while rendering" checked:on

edittext filename "File name:" text:"my_filename"
edittext extension "File type:" text:".jpg"

button doRender "Do the render"

on doRender pressed do (
a = splitcount.state
b = splitcount.state * splitcount.state
-- actual render width and height
w = width.value / a
h = height.value / a

bm = bitmap w h
p = overlap.value - 1

for i=0 to b-1 do
(
row = i / a
col = i - floor(row) * a

render renderType:#blowup region:#((w/a)*col,(h/a)*row,w/a*(col+1)+p,(h/a)*(row+1)+p) outputwidth:w outputheight:h outputfile:(filename.text + row as string + col as string + extension.text) vfb:show.checked progressbar:(not show.checked) to:bm
)
unDisplay bm
)
)

-- create the rollout window and add the rollout
if splitRenderFloater != undefined do
(
closerolloutfloater splitRenderFloater
)
SplitRenderFloater = newRolloutFloater "Split Render Tool" 250 225
addRollout SplitRender SplitRenderFloater

[Spacelord]

Don't know, it's still rendering ;-))

nisus

Hey Nisus,
you finished that render ? :) haha

[blueshavu]

Hello, I have the same problem with MAX2009design... I´ve to render to blowup and match in photoshop... a waste of time really.
please if anyone knows how to post it

thanks all

[nisus]

Héhé, yeah most renders are done by now ,-p

20min for a 3800px wide image with tons of trees and lights and nice materials with glossy reflections... yeah right... (read: not!)...
Afterall we are 3009 already, aren't we?

rgds,

nisus

[charlydue]

[QUOTE=MasterZap;2028]A little bit of MaxScript perhaps?

I love you Zap

As seen on TV... It's changed my life

[charlydue]

I've found this:

http://www.neilblevins.com/cg_education/reducing_memory/reducing_memory.htm

ALSO:
For those wandering what VFB is
Virtual Frame Buffer= Rendered Frame Window and can be found at
Render Setup>Common>Render Output

[charlydue]

I've found this:

http://www.neilblevins.com/cg_education/reducing_memory/reducing_memory.htm

[nisus]

Hey Nisus,
you finished that render ? haha

Almost done now... 22% ,-p

nisus