Mental Ray "Memory Limit"

[Matt McDonald]

I'm kind of new to Mental Ray and noticed in the Render Dialog on the Processing tab there is an option called "Memory Limit" mine is currently set at 650mb.

 

I read about the option in the help menu and it sounds like this setting controls the balance of memory allocated for textures vs. geometry. It also sounds like if the setting is not quite correct Mental Ray will still allocate memory appropriately but it may do so more slowly. It also indicates that the default is 1024mb.

 

I am I interpreting the setting correctly and does anyone have any advice on how I should set it and why?

 

I am running Max 9 on x64 and my machine has 4Gb of RAM.

 

Thanks for the help.

Matt

[manish_mv]

We ll it is basically the the memory usage of mental ray while rendering which you can increase or decrease any time. Now it needs to be increased if the scene is taking a lot of time in translation of the scene it means you can devote more system resources on it you can easily increase it as per your system configuration as you have 4 gb of ram you may allocate 3 gb i.e. 3072 mb and rest 4 other programs but remember standard 32 bit xp doesnt support more than 1.5 gb of ram to utilise ur 4gb ram you must have a 64 bit os installed with 64 bit max.

[Tommy Burns]

What should the Page Size, Bitmap Size Threshold and Memory Pool setting be at for a normal 32bit quad core workstation with 2.75gb Ram

does anyone know?

 

Thanks in advance

[Matt McDonald]

Tommy, I have yet to really dive into the bitmap pager but I have finally found some pretty good info on my original question.

 

Manish_MV, now that I have learned more about this function your answer makes more sense to me than it did originally. Thanks for the help.

 

So here is what I have figured out:

 

The memory limit setting is like a warning track. It tells mental ray ”hey buddy, if you start using this much RAM on your own then you need to start flushing objects from memory or you are going to crash and burn!”. I created a scene with 2500 teapots, dropped in an MR sun & sky and rendering with the default 650mb memory limit. Max used 479 megs of RAM and rendered in 26 seconds. I then set the memory limit up to 2048mb and it rendered using (basically) the same amount of max memory in the same amount of time. I then dropped the memory limit to 100mb. The scene only used 409 megs of RAM (most of the time sticking around 380) and it rendered in 1 minute 12 seconds.

 

So I guess the rule of thumb is to figure out how much memory your system has available while idling (with your Max file open) and then figure out how much memory you still have available, then set your max memory lower than that number for cushion (remember, my scene poked up to 409mb, by the books it shouldn’t have passed 331mb, but my max memory was ridiculously small).

[manish_mv]

Hey Nice !

 

Thank you