Mental Ray struggles

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  04 April 2003
Mental Ray struggles

Im doing some tests using Maya 4.5 and Mental Ray 1.5.1.

Im using TGA test images off 2000x2000, 4000x4000 and 6000x6000. Maya's renderer can handle the images just fine, but mental ray shuts maya down with the 6k render. (And isnt too stable on the 4k one.)

Its been spitting out errors saying its low on memory and the classic "exception thrown" error.

I am on an AMD XP 2000+, 1 Gig of Ram and have a 350 meg page file.

Any suggestions here, or is a 6kx6k texture just a bad idea overall?

I'de also like to add that I've tried saving out the textures as high resolution JPG's (Which maya can't read for some reason.) And as Maya IFF files (Which adobe crashes when I try and save images bigger than 2k by 2k)

Thanks...!

Mike R
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Mike Rhone
-VFX Artist-

Dust Rig - tutorial for Maya

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Last edited by Rhonedog : 04 April 2003 at 12:31 AM.
 
  04 April 2003
Just a bit of general advice. Your page / swap file should be similar in size to your RAM.

Maybe if you give yourself a bigger page file you might get less crashes?
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Bliz::..

homepage:www.anthonyrosbottom.com
 
  04 April 2003
i'm not too savvy with big renderings, but if i remember correctly from what i read tuning the BSP settings can fix out of memory errors
 
  04 April 2003
oh, and memory mapped textures could help you too - take a look at the imf_copy utility and memory mapped textures in the mental ray reference manual
 
  04 April 2003
Check your geometry approximation settings carefully - at default settings MR often ends up tesselating into far more polygons than the Maya renderer does - and that eats memory for lunch.

-jeremy
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Jeremy Birn
Author, Digital Lighting & Rendering, 3rd Edition
 
  04 April 2003
Thanks for the help so far people.

I've upped my page file to a gig, and have messed with the BSP settings. As for my geometry approximation settings Jeremy, I'm using plain old polygons, so there no optimizing to do as far as I can see. (The options are grayed out on polygonal meshes)

When it does crash, I get the windows C++ Warning:
Runtime Error!
Program: C:\ProgramFiles....maya.exe
Abnormal program termination

Under memeory and performance options, I have tried BSP and Grid, as well as dropped the BSP settings way down. I will admit that I dont know anything about those settings though. Im just mashing keys here

Maya/Mental ray seems to be stable up until I increase the sampling Quality from the min=0 Max=2 settings I use to preview, to 1,3 or 2,4.

So I'm left with the same questions I had before: Why does maya not like textures bigger than 4k x 4k, and why does increase the sampling quaility crash maya?

Are there any other suggestions? I can accept a LONG render time, just no crashies
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Mike Rhone
-VFX Artist-

Dust Rig - tutorial for Maya

Tonga the Fox - Free cartoony rig for Maya!
 
  04 April 2003
I think it's not Mental Ray but Maya, I get these damn memory exceptions flying all over the place when I try to render big files with lots of detailed hierarchical SubD's with lots of hi-res textures - which is just about all my renderings, since that's what it takes to do realistic human characters... yet I have 2 Gb of RAM... grr
 
  04 April 2003
Quote: Originally posted by Rhonedog
Under memeory and performance options, I have tried BSP and Grid, as well as dropped the BSP settings way down. I will admit that I dont know anything about those settings though. Im just mashing keys here


In terms of BSP settings, higher tree depth = more memory usage, and smaller leaf size = more memory usage - so you don't just lower all the numbers.

-jeremy
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Jeremy Birn
Author, Digital Lighting & Rendering, 3rd Edition
 
  04 April 2003
Thanks for the info Jeremy. I'll cease with the mashing.

Stahlberg, I'll join you in your ranting... I dont know if you're having the EXACT same probelms as me, but do you have any work arounds that may help? A 4k texture shouldnt be able to kill any program, and its been the same with maya 4.0 and 4.5.

Only with the MR renderer though. (Except when I tried loading the 6k texture, maya crashed before I even got chance to hit the render button)

Thx for the help so far everyone.

m

P.S. This is the error I get from the output window:


====================================
Cause of memory exception
====================================
372.641 Mb Free Memory
1363.500 Mb Free Swap
137.329 Mb Size of alloc
10.000 Mb Low Memory Threshold
====================================
Memory use when exception was thrown
====================================
====================================
2177 Page faults
379.785 Mb Peak total size(Estimated)
241.666 Mb Peak arena size
====================================
379.238 Mb Current
25.000 Mb MEL
13.203 Mb Arrays
0.031 Mb Pixel Map
0.844 Mb Object Arrays
0.313 Mb NURBS Geometry Cache
1.000 Mb NURBS AG
185.364 Mb File Texture Mipmaps
0.125 Mb NURBS Surface Shapes
10.667 Mb Render Cache
0.249 Mb Transforms
0.938 Mb Data Blocks
====================================
__________________
Mike Rhone
-VFX Artist-

Dust Rig - tutorial for Maya

Tonga the Fox - Free cartoony rig for Maya!

Last edited by Rhonedog : 04 April 2003 at 08:05 AM.
 
  04 April 2003
A 4k x 4k texture ??!!!! Admittedly I don't know what you intend to use the end result for but are you sure you need a 4k x 4k texture?

Even if you need such a large texture for the colour and bump maps, imho you don't need the same res. for specular, diffuse and all the other material options available. Even a colour map that high can be made reduncent with some good vertex colouring working with a lower res colour map.

Or could you break your scenes into different texture sets? e.g. 2k square face texture for close up head shots, a 1k square whole body texture for medium range, full body shots etc. etc.
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Cheers,
Bliz::..

homepage:www.anthonyrosbottom.com
 
  12 December 2003
I have been trying to get a scene to render for too long in Mental Ray and have been getting the runtime error over and over again. Missery loves company because I am now glad I am not the only one. I have been to other forums and others do not seem to be running into this problem. As I write this I hear the base drum of another runtime error. arrrgggg. What the hell to I have to do to get a great render out of Maya. It has no problem when the scene is simple. It will render a great set of chair.

The maya render will hit 2.5 gigs with virtaul. Mental ray will not pass 1.7.

I have 1 gig ram. I am running a XP 2500 Barton
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Just one more render and will go to bed.......Is that the sun coming out??????

Last edited by RickStefani : 12 December 2003 at 01:42 AM.
 
  12 December 2003
use the disk based texture maps.. Saves tons of ram.
 
  12 December 2003
Quote: Originally posted by Bliz
A 4k x 4k texture ??!!!! Admittedly I don't know what you intend to use the end result for but are you sure you need a 4k x 4k texture?

Even if you need such a large texture for the colour and bump maps, imho you don't need the same res. for specular, diffuse and all the other material options available. Even a colour map that high can be made reduncent with some good vertex colouring working with a lower res colour map.

Or could you break your scenes into different texture sets? e.g. 2k square face texture for close up head shots, a 1k square whole body texture for medium range, full body shots etc. etc.


4kx4k's not that bad, it's certainly necessary for realistic texturing of characters if the UVs aren't broken up into sets (something I haven't figured out how to do reliably yet myself). Heck, depending on how close up the camera goes, one might need a 4k map just for the head for fine bump-mapping detail like lip-wrinkles. Also, for large ground planes that don't tile, one would need massive texture sizes too.
 
  12 December 2003
I rather work with four 2k textures then one 4k textures. You then will have the same amount of pixels, but Maya can handle these kind of sizes better (specialy on my computer, it's 3 years old now).
Off course you can work on one large 4k texture in photoshop, and then splitting it up for usage in Maya.
You only have to do a bit more of mapping.

:: Galactor ::
 
  12 December 2003
Thanks for the tip on saving ram but To the task at hand, are you saying that the problem is that mental ray will not work with virtual memory? So I have to go buy two more gig, (three total) to render complex scenes? I am already compositing the three images.

What is the comonality to all of us that are having the mentalray shutdown. There are people out there that are not having the problem. There must be a conflict somewhere.
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Just one more render and will go to bed.......Is that the sun coming out??????
 
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