[rzick]

Can't seem to figure out exactly what is happening, but I keep getting intermitent crashing when trying to export a large scene. I've added an additional object and now I can't export anything without it crashing Layout. Seems like the frequency increaes as the size of the MXS increases. Right now it is around 400 meg. I have eneough memory, even though about 1.3 gig is consumed by LW.

I don't really think it is a memory issue and was wondering if anyone else has had this behavior. The crash occurs at different points in the export process, not always at the same place. If I remove an object (any object) and bring the resulting size of the MXS down it won't crash. Seems like I can't get it above 400 meg.

??????

[Mihnea Balta]

Are you using 32-bit or 64-bit Lightwave? If LW is already using 1.3 GB and the MXS is 400 MB, you're at 1.7 MB, which is very close to the 2 GB limit for 32-bit applications.

[rzick]

32 Bit. I wasn't aware that you can only have up to 2 gig loaded into memory at one time on a 32 bit application. Why in the world would you install more than 2 gig of RAM in that case? If anything, I would think it would write to the page file.

[Mihnea Balta]

Having more than 2 GB of RAM with a 32-bit OS only helps if you need to run several memory-hungry applications at the same time. It can also help with disk access times in some cases, because there's more room for OS buffers.

As you probably know, a 32-bit OS can only access 4 GB of memory (because the largest number you can represent with 32 bits is just over 4 billion). Windows divides this space into two halves for each application. The bottom 2 GB are usable by the application directly, the other 2 GB are used by OS services, drivers and so on. The other 2 GB aren't necessarily system RAM, it's just a space where the OS can map things without giving applications direct access (for example, some of it will point to the memory on your video card). It doesn't matter how much RAM you have or how big the swap file is.

Windows can be configured to allocate 3 GB of address space to applications and only 1 GB to the kernel with the /3GB boot flag (see here for an example). However, this can affect the stability of the system or some programs and it might not always help if the application itself makes assumptions about pointers having their top bit clear. Make sure you have at least SP2 before trying this, XP SP1 sometimes refuses to boot if you add that flag.

The simplest fix is, of course, to use a 64-bit OS and 64-bit LW, but unfortunately it's not the cheapest one.