« on: July 03, 2015, 08:04:32 PM »
Meshmixer will not inherently crash from "insufficient RAM" on any computer that has virtual memory enabled (IE all modern computers, unless you disabled it explicitly for some reason). If you set a hard limit on your system's virtual memory usage, *or* you run out of hard-disk space for virtual memory, then it will crash because the operating system will not be able to give us more memory to use.
Except in the cases of significant memory leaks (which can occur but usually are quite obvious and we find them quickly), the vast majority of RAM usage is just to store the triangles of your mesh (including undo history), the rendering data structures, and the spatial data structures we need to efficiently manipulate the mesh. These are about as compact as we can make them. We can use less memory, but then the operations will be slower - this is an unavoidable trade-off. Our preference is to use more memory and have more interactivity.
On a modern CPU/GPU with sufficient RAM, you can work with up to about 5 million triangles in the active object. Larger than this and the compute and rendering overhead starts to slow things down too much. In these cases more RAM will *not* help. When I say "sufficient RAM", my guess would be 8GB, I have a 64-bit system at home with 8GB and I can work with the same files I use on a larger machine. However, I can't also be running a ton of other stuff.
We have used much larger files (I test sometimes with a 10M triangle file, and at least one user has reported loading in a 36M triangle file). This requires more RAM, but it won't crash if you have the disk space for the virtual memory. However it will be incredibly slow (the rendering will grind to a halt) and this makes many tools unusable.
If you want to work with huge files, please try Autodesk Memento. This software (also free) makes a different trade-off, it handles arbitrarily-large files but doesn't provide the range of interactive tools that meshmixer does.