How big should projects be limited to? I've got a 3dm file that's over 100mb, is that going to start causing problems for Moi? Is there a general rule of thumb when working on a complex object with a lot of parts?

Hi Jim, it's hard to put any one specific limit on that because a lot can depend on what hardware you're running on.

For example if you're running on a small netbook computer with limited RAM, that's going to have a much significantly smaller maximum workable file size than a quad-core desktop machine with maxed out memory.

So it's pretty situational...

100mb is not necessarily going to cause any problems with MoI, but that is getting on the fairly largish side and somewhere much more than that neighborhood you could need to start doing things like separating things out into multiple files instead of having everything all in one single big file. But it all depends on whether you're seeing things bog down though.

If things are bogging down, one thing you can do to reduce memory consumption is to make the display mesh density to be rougher - to do that go to Options > View > Meshing parameters, and change "Mesh angle" from its default of 10 degrees to something more like 25 degrees, and uncheck "Add detail to inflections".

That will make for a somewhat rougher looking shaded appearance of surfaces but it will also reduce memory consumption by quite a bit on heavy models.

- Michael

OK, thanks for the quick reply! Man, do you ever get out? Why aren't you out partying it up on a Friday night!?
Anyhow, if I break things up, at that point I'm then forced to work on individual sections and I can't see it all together any more, correct?

Hi Jim,

> Anyhow, if I break things up, at that point I'm then forced
> to work on individual sections and I can't see it all together
> any more, correct?

Yeah, that's the tradeoff. But if you're exporting pieces to a renderer anyway you could view them all together there in there in the rendering environment.

Another thing you can do is just hide pieces that are making things sluggish, then you can show those big pieces to temporarily see the full thing, it's not too bad to have things bogged down when you're just doing a quick overview, then hide them again to go back to work on any one particular piece.

Another thing that can speed things up a lot is if you just hide edges in the model - often times on a complex model drawing the edges actually takes the most amount of time so if they are hidden it can make for a big display speedup.

- Michael

At the moment I'm working with a 190mb Moi file. all is layered and objects named, so it's easy to switch things on and off to work on them or have them in the background.

Another thing you might take into consideration: the amount of RAM that is used. With my file I'm close to 1.5gb RAM usage and I experienced some strange crashes of MoI that never occured ever before when I tried to export too many things at once via .obj. Otherwise it works as a treat and I can only say that MoI saved my ass on the current job.
As I don't see a 64bit version mentioned anywhere this might be a bottle neck in future for me - any plans to change that Michael?

Michael - Is MoI large address aware? Is it possible to turn this on? I know it has worked wonders for a few other programs I use on my workstation (well, any x64 machine with 4+ GB).

Thanks, I'm not having any problems so far, but I was concerned that it might get too big and then the saves would crap out leaving you with a corrupted file.

Hi macray,

> Another thing you might take into consideration: the
> amount of RAM that is used.

Yes, that's actually what limits things - not really file disk size specifically.

When a file is loaded, the memory consumption of it in RAM is a lot more than just the disk size, for a lot of various reasons but one big one is information calculated for the display.

If you're working with large files that are getting close to the maximum amount of memory that can be used (about 1.6 GB on a 32-bit system, or something like 3.6 GB on a 64-bit system) you can help reduce memory consumption by turning down the display settings as mentioned in the 2nd post in this thread. The lower density display mesh will look a bit chunkier than the default one but it will reduce memory use by quite a bit.

You can also make more memory available to MoI by just running it on a 64-bit system instead of a 32-bit system - even though MoI is a 32-bit program if you run it on a 64-bit system it will have twice as much memory available for it to use. That's because on a 32-bit system the upper half of the 32-bit memory address range is reserved for use by the operating system, but on a 64-bit system that's not the case and the full 32-bit address range is given to the application to use.


> With my file I'm close to 1.5gb RAM usage and I experienced some
> strange crashes of MoI that never occured ever before when I tried
> to export too many things at once via .obj.

Yes, running out of memory is a particularly tricky thing to guard against, it's probably the easiest way to crash MoI. Unfortunately it's a particularly difficult thing to deal with well because it can alter program code flow at quite a lot of different points.

So to make things run smoothly you don't really want to hit an out of memory situation at all, keep a bit more of a buffer before that happens - lower display settings, or work on things as separate files instead when you are getting close to this limit.


> As I don't see a 64bit version mentioned anywhere this
> might be a bottle neck in future for me - any plans to
> change that Michael?

It takes quite a bit of work to maintain multiple versions at the same time, so right now I don't really have any specific plans to have a 64-bit version. Maybe at some point in the future when I can just switch to only have that and not a 32-bit version at all, but that will probably be quite a while.

There are actually other things that are more important than that for handling large data sets, like having an instancing system.

But as I mentioned above, there are benefits to running the current 32-bit version on a 64-bit operating system, you actually get double (or even a bit more than double actually) the amount of addressable memory if you do that.

So if you're getting close to a 1.6 GB RAM usage right now, running on a 64-bit operating system would actually help deal with that.

- Michael

Hi Nick,

> Michael - Is MoI large address aware?

Yup MoI.exe is already marked as large address aware.

That means that on a 64-bit system, the operating system will allow MoI to use the upper half of the 32-bit address range for its own use rather than having it reserved for the operating system's use.

So when you're running MoI on a 64-bit operating system, it is able to use something like 2GB more RAM than if you're running on a 32-bit operating system.


> Is it possible to turn this on?

It is turned on already, so you don't need to do anything special to activate this, other than just having a 64-bit operating system.


- Michael

Unfortunately there is no option for 64bit windows here. Will see that I get used to work on separate files if this goes on. (64bit windows is foreseen for the next company laptop. Order is given, but no clue when in ht next months this will be there so it will for sure take some more time to work in 32bit...)

My main concern at the moment: I don't want to switch to some new (to me) cad system to be able to design the things I need to do now. So to have a 64bit moi would help. For a while the work via separate files will have to make do.

Hi macray,

> For a while the work via separate files will have to make do.

Don't forget the display density adjustment too - that actually makes a pretty big difference to reduce RAM usage on heavier models.

Go to Options > View > Meshing parameters (the settings at the top), and set Mesh angle = 25 degrees, and uncheck "Add detail to inflections".

The display will look a bit more jaggedy but memory use will go down by a chunk.

- Michael

As this is mainly about piping-this should be helpful. Thanks for pointing at it again.

Hi macray - yeah piping tends to make a particularly heavy display mesh so you'll probably see a pretty good memory reduction with the rougher display settings.

Another thing that I'd like to try in the future is something more like make an initial rough display mesh for everything and then go through and in the background calculate denser and smoother ones but only if there is plenty of memory still available.

- Michael

>Yup MoI.exe is already marked as large address aware.

Awesome. Thanks.