Hi Sebastian - there is no particular file size limit but there is a runtime memory size limit that MoI cannot use more than about 3.6GB of memory , or about 1.6 GB if you are on a 32-bit operating system. That's because MoI is a 32-bit program.

Runtime memory usage is a little different than just plain file size, because a lot of additional things like display mesh data are calculated for the runtime display, so there will usually be a quite a bit more memory consumed at runtime than just the file size.

679Mb is a quite large file though, and I'd generally recommend breaking something of that size up into a couple of different files, until your runtime memory consumption does not reach that approx 3.6GB limit - check the memory consumption of MoI.exe in Task Manager every once in a while to see if you are approaching that. A lot of things will generally stop to function if you actually hit the limit so it's best to leave a bit of cushion to make sure that you do not actually hit the limit and run into failed allocations.

Another thing that can help a lot is if you turn down the display mesh density to make coarser display meshes. That will make for a somewhat rougher looking display but it trims down runtime memory consumption by quite a bit. See this post about what settings to adjust for that:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4643.4

- Michael

Thanks Michael. I think you nailed it with the runtime memory. I have been monitoring memory usage and that is when it seem to start giving me headaches. And I can't break it up 'cos MoI always gives up the ghost. Question then: if I lessen the display mesh will that affect the quality of the model when I export it?

UPDATE: Set the value to 5 (was 0.2) and unchecked inflections and its worked!! What I have been trying to achieve the last 2 days worked in under a minute!!! Very happy. Now please excuse while I go kick myself. Hard. Several times.

Hi Sebastian,
.02 for the display angle? Yes, this would be overkill. 5 would still be quite high. I think MoI's default is 10 but i work at a lower angle too, but I am not loading 600 mb files.

The mesh angle will not affect accuracy at all. It's just what your looking at in the MoI viewport. If you set to coarse, then zoom way in, you would have to learn to trust the numbers and add some other techniques to model accuratly, because at the higher zoom level, things can start to appear "off" from what they actually are.

5 has got you going, but dont be afraid to try working at 10 (10 would still be better than "most other systems")

Hi Sebastian,

> And I can't break it up 'cos MoI always gives up the ghost.

To split it up into smaller files, try selecting some objects (like maybe just half is fine) and then write only those objects to a new file using File > Export. Then don't delete them since that will create a huge undo unit - instead use Select > Invert to flip the selection around and then do another export.

That should help to break the file down into 2 separate files.

- Michael

> I have been monitoring memory usage and that is
> when it seem to start giving me headaches.

Yeah all kinds of actions require allocating some memory at least for a while to do stuff, so everything will start to fail if it reaches the "memory totally full" type state - you want to try to never reach that point.


> Question then: if I lessen the display mesh will that affect the
> quality of the model when I export it?

Nope, the export mesh is calculated totally separately from the display mesh, so the display mesh setting has nothing to do with the export.

- Michael

Hi Sebastian,

> UPDATE: Set the value to 5 (was 0.2) and unchecked
> inflections and its worked!!

Yeah 0.2 is extremely tight - that's asking for only a deviation of 0.2 angular degrees between surface normals of the display mesh, so that's going to generate a tremendous number of triangles.

Even 5 degrees is still quite tight - the default is 10 and even that is on the tighter side.

If you are working with large files I would recommend setting "Mesh angle" to 25 degrees (25, not 2.5) and uncheck "Add detail to inflections" and that will help lessen the memory load by quite a bit.

- Michael

Thanks for the replies, everyone. Like I said, I got it sorted and learned something too :)