Mental ray crashing due to memory

[kiwi3d]

I had this exact problem today, Was rendering a large scene, and it would render about 200 odd frames then crash, I set it off again and watched the task manager and you could see the ram usage slowly climb up to the point it ran out of ram. Only solution i came up with was to render out 150 frames at a time, then reboot the pc and render out another 150.

[neogeo51]

Hi I had the same problem with XSI 32bit at the last job. If you have to stick to xsi32 try optimizing the objects in your scene via poly reduction e.g.. In the render options under optimization turn on dynamic bsp tree and set both memory limits to your needs depending on how much memory your workstation has. Keep in mind that windows also needs some ram to run. With the same scene form that job I run a test render on one of my XSI 64bit workstations and the rendering worked fine without any errors. But the render process catched about 4 to 6 GB of RAM during render.

[CiaranM]

Hi,
what are your BSP settings like?
What is the render bucket size (smaller = less memory)?
Are you using Foundation? If not, have you tried to render from command line?

Cheers.

[SFDD]

Hi there I am using MR to render a scene but I get this error message after a while.. Any ideas how to fix it?

Hey IpiotisDinos:

I'm a relative XSI newbie, so please don't take this as anything more than one guy's experience. During my first big project with XSI, I also ran into a mental ray memory error. Things went fine for a few hunderd frames and then the whole thing would error and die on me. After adding another 2GB of RAM to my machine didn't help, I realized the error was actually caused by an error in one of my shaders. (I was using the cell shader piped into a specular port. Don't ask me why it caused the error, but it did.) Anyway, once I sorted that out, I no longer got the errors.

The "hint" I had was that I was getting a random error on the status bar when the offending object was selected. It didn't seem to cause any problems during test renders, however, so I ignored it. (I wish I could recall what the error was, but I've blocked that entire horrible week from my mind now.) But a few hundred frames into it, and wham.

Anyway, I though I'd bring this up just in case.

[scottsch]

If you are running out of memory, check your shaders. There may be one that has a IOR that's causing more calculations to occur which requires more ram.

I discovered something important this week about the architectural material shader. If you check "optimize" reflections (shader tabs - optimize - refractions - enable checkbox), it will make nicer glossy reflections that render faster BUT it will also cause mental ray to gobble ram by leaps and bounds... and crash XSI if it hits your physical memory limit.

I found this out because I couldn't figure out why a scene was crashing after importing some basic models. I opened taskman and noticed the ram usage was ridiculous. It turned out that they had optimize>reflection>enabled in their architectural material, and turning it off stopped the crashing and extra ram use.

This is probably a bug in mental ray.

[Saturn]

hmmm why not specifying a memory limit ?
Mr crash because you reach the physical memory limit ( 2 GB ). limit it ( 512 Mb ) and it will never crash for this reason.

[scottsch]

Sometimes mental ray disregards the memory limit you set in render options. The above case is one example, which is why I think it's a bug. My memory limit was set to 800MB and mental ray blew past it within 20 seconds of starting the render and then crashed at the 1,600MB mark as it hit a memory allocation error.

I should also point out that in the scene I was working with, turning off optimize reflection in the archmat shader brought memory usage down to no more than 450MB during the entire rendering - versus a crash at 1600MB with optimize reflection turned on.

Having both reflection and refraction optimize turned on makes the memory problem even worse, btw.

[adrencg]

maybe this is a frustrating answer, but for me this was an extremely frustrating problem ---and setting memory limits and mesh splitting made render times go through the roof.

I went over to 64bit and bought 4 x 2gb sticks.

8GB ram = no more memory problems.

4GB should do just fine for most things, but I'm a scene abuser.

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