I am trying to import as STP file which is 375mb in size. MOI thinks about it for about 20mins and then gives me a file with nothing inside. Does MOI have an upper limit of the file size it can import?
I have a mac with 12GB of RAM . ..
Matt j

I've had this problem before, usually caused by block definitions inside the step file.

If you have Rhino you can open, explode the blocks, save, and open in MoI.

Anyone have any solutions if you don't have Rhino to fall back on?

Hi Matt, MoI is just plain old running out of available memory when that happens. MoI is a 32-bit program so it's only actually able to use 4GB of your memory and a 375mb file is quite large in size. You will probably need to get that exported out from whatever application is writing it into a few separate files instead of one single gigantic file.

> Does MOI have an upper limit of the file size it can import?

There is no one specific limit, since it depends on what kinds of things are in the file - for example like AW mentions above if there are a lot of block instances inside the file that will balloon into a much larger size in memory at load time as they each become an individual object at load time into MoI right now.

Also if the object has a whole lot of little tightly curved pieces in it, that will consume more memory for display mesh generation when it is loaded.

You can lighten the memory load somewhat by changing a setting to use a rougher display mesh, that's a setting under Options > View as described here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=4643.2

Setting the "Mesh angle" to a rougher angle like 25 degrees and unchecking "Add detail to inflections" will make for a somewhat rougher looking display but also lighten up the density of the display meshes and that can help reduce memory consumption by quite a bit on more complex models.

But still it is somewhat doubtful that a huge 375 mb file will be able to be loaded all in one single chunk, you will still likely need to have it broken into a couple of pieces instead.

- Michael

Thanks for the answers, I guess it makes sense. Smaller files it is then.
A cheeky question - is a 64bit version ever likely?
matt

Hi matt,

> A cheeky question - is a 64bit version ever likely?

Probably at some point yes, but it's likely to be quite a few years away. It will be a pretty major effort to do it since it will involve an across the board update to a lot of things including using a new compiler, and updates to all libraries.

It will be similar in some sense to producing a new operating system version, and right now I've basically spent the past 6 months already doing that similar kind of thing to produce the Mac version already, so I'm not really enthusiastic about turning right around and doing another generally similar type of work right away...

That kind of work is actually somewhat dangerous for me to dig into because it involves a huge amount of work and then at the end of all that work what pops out the end is actually for a lot of people no different than what I had before, because the 64-bit version will produce absolutely zero benefits for people who are not dealing with huge data.

So I have to weigh that (the "absolutely zero benefits to a lot of people") against the amount of work required, and that's what makes it not a good "bang for the buck" type of work for me to focus on as a priority right now.

The sort of core concept and focus for MoI is much more that it's a tool for drawing and creating new things, and importing a 375mb STEP file is not really so much aligned with those goals in the first place really. It's sort of more of a side effect that MoI is good at that kind of CAD file conversion to polygons since it has a high quality mesh creation mechanism, and I certainly don't object to people using MoI just for file conversion (many do use it just for that because of its mesh quality) but it's not really the core mission.

Then on top of all of that, I think it's likely that some particular feature areas like implementing an instancing mechanism to better deal with highly repeated objects could probably enable a much better handling of large data files in many cases than 64-bit-ness actually...

- Michael

Thanks for that long reply micheal. For me MOI is both the easiest modeller and the best converter around!! Please take that as a compliment ;-) I regular work with huge files (i work in the aircraft industry). We also bought CAD loader from luxologu to go with Modo and in my opinion its not a patch on MOI - OK it has nice features where you can assign different levels of mesh details to different parts, however if it has to deal with a large file (+10mb) it is very slow and cumbersome. In my experience in 3D (15 years) the files are not getting any smaller so I need to be able to crack open these files. I have worked with 280mb files in moi in past and it was OK. Maybe it could be a possibility to develop an add on that first looks into the structure of a STP file and you can select just sections of the file at a time to import and convert . . ? But then what do i know . .just a thought?
BTW i do use MOI for about 50% of my modelling, and I use the MAC so i can't thank you enough for pulling that off recently - great work!
matt

Hi matt, I'm glad that you're making use of MoI for modeling too!

> Maybe it could be a possibility to develop an add on that first looks into
> the structure of a STP file and you can select just sections of the file
> at a time to import and convert . . ? But then what do i know . .just
> a thought?

Unfortunately the details of dealing with STEP format are pretty darn complicated, so MoI's STEP import is handled for me by a library that I license - I'm not sure that right now that library is structured in such a way that it exposes that information of just structure alone and being able to selectively import. It's probably something that would need to be developed and added into that library first before MoI would be able to make use of it.

- Michael