I cannot seem to export as igs and stp, which are vitally important as I need to continue work on some models in Alibre Design. Whenever I try to export the program just hangs, the does that spinning thing. If I try to minimize the window I get a message that the program is not responding and do I want to shut down or wait or look for a solution on the internet.

The model is 84Mb in size. Not the largest be any means. Also I tried import the 3dm straight into Alibre but got the following result:










Why won't it export?

Hi bigseb - how long are you waiting for it to complete the export?

With a large model like that it could possibly take a while for the exporter to crunch through the entire saving process.

While it is busy working it will look froze up like that and give you that "not responding" type message if you try to mess around with it while it is busy working.

If you look in task manager and it is still consuming CPU that means that it's just busy working away and you probably just have to be a little more patient and wait for a few minutes for it to do its work.

In v3 I want to make things look nicer when it's crunching away on a big import or export like this, instead of it appearing frozen but for the time being if it is crunching away just let it do its thing for a while.

- Michael

Not sure now if I waited 1 hour or two for it finish. Either way it's long. How can I tell if it is actually doing something?

Any chance V3 will run on multiple cores? Might speed thing up....

Hi bigseb, that's a pretty long time to wait.

> How can I tell if it is actually doing something?

If you open up Windows task manager and look at the line for MoI.exe and it has activity in the CPU column, that means that it is still crunching away and not actually crashed.

Is it possible that you've maxed out memory consumption or something like that ?


> Any chance V3 will run on multiple cores? Might speed thing up....

MoI does use multiple cores currently for the mesh generation stage when exporting to a polygon mesh format.

Making use of multiple cores is a very delicate and error prone operation though, it involves splitting things up into a lot of smaller separate tasks that can be executed in parallel and then carefully coordinating them when they finish.

It's not something that you just turn a switch on and it automatically gives improvements, it takes a lot of special work to make use of multiple cores and it also is only suited for types of calculations that can be split up into small pieces.

I do want to make use of multiple cores in some more situations in MoI in the future but it tends to be an area that requires a lot of careful work.

- Michael

I have an i7-870 and 8Gb RAM, that should be plenty crunching power. Here is a snapshot of the task manager:

Hi Sebastian, so that 13% indicates that it's still crunching away on one core calculating something.

It only shows 13% because it's only going on one of your 8 CPU cores, but that still means it's not actually crashed, but there may be some other kind of a problem than an actual crash like stuck in an infinite loop somehow, although I have not seen that happen before with the exporters.

Is this with MoI v3? Can you try with v2 and see if there is different behavior in v2?

Can you possibly send the file to me so I can test with it over here? I guess you would need to use some kind of service like Dropbox or Windows SkyDrive since it's too big to send through e-mail.

- Michael

The zipped file is only 12MB so emailing is possible...

Hi Sebastian - you can try to e-mail it to me at moi@moi3d.com, it still may be a bit too big though but I'm not sure.

- Michael

Also the part that looks complex about your model there is what looks like several hundred little holes drilled into one area.

If you want to get this into Alibre right now you might try exporting just the main body in it without those holes and do the hole drilling inside Alibre instead, that would make for a more simple structured export.

- Michael

Another thing that might be an issue is that the holes look like they're quite teeny-tiny in size.

You might try scaling the model up in size by 10 times or so and see if having not quite so tiny features goes better as well.


Those are just a couple of ideas that might help until I can figure out why the export is taking so long.

- Michael

"try exporting just the main body in it without those holes and do the hole drilling inside Alibre instead"

I had considered that but its not how it should work either.

The holes are 2mm in diameter, 2880 off.

The email has been sent, I hope it helps. I used 7zip to zip it.

> I had considered that but its not how it should work either.

Agreed, but if you want to get a model transferred right now that could be one way to get it done.

You also might look at some of the 3DM import settings and change some options in there - possibly turning off "model healing" may help since that could make it do less fiddling around with the imported data.

- Michael

Hi Sebastian, thanks I got the file through e-mail.

Over here I tested with a slightly older version of Alibre's using 3DM import, and it seems to come in if you don't enable the "healing" option.

Here are the options I used:



Then importing the 3DM into Alibre gives this result:





There seems to be some problem with the display mesh not being right one some of those little holes:




That looks like it is probably a display issue where the display mesh is not getting generated properly, a single surface with thousands of little holes is a pretty big stress test for any triangulation mechanism, and I think it's likely that only the display triangulation of those areas is messed up and not the actual NURBS model geometry itself. That may cause you some problems if you need to rely on the Alibre triangulator for generating output to the special KeyShot Alibre version that doesn't have the regular file import options. Normally to get a better triangulation you would want to use MoI to export the mesh instead, but your renderer needs to support the normal render interchange file formats such as OBJ format for that to work.

I'm running a part check in Alibre to see if it checks out ok but it's taking a really long time to run.

So using the above settings for the 3DM import into Alibre may do the trick for you right now, although it looks you may run into problems with this kind of geometry if you need to rely on Alibre's triangulator for mesh generation.

- Michael

Hi Sebastian, I'm pretty sure that those filled in holes in the Alibre import are a display mesh generation problem and not actually bad geometry. I also tested importing a 3DM of just the one single face with the numerous holes in it like this:



If you spin it around and look at this single surface from the backside, you can see all the trim curves for the holes are actually there but some bad triangles have been created between some of the holes:




That's really looking like a triangulation issue - probably the base geometry itself like the actual surface and edges are ok here and could be used for operations that work directly off of the geometry.

This kind of situation with one single surface that has a lot of little interior holes in it tends to be somewhat difficult for triangulators to handle, so that's not entirely surprising to see some problems in that area. If you need Alibre's triangulator to handle this you may need to split it up so that it's made up of a few long strips of surfaces instead of one big surface that has so many little internal trim holes inside of it.

- Michael

Michael,

I know I mentioned this in the email but I'll repeat for the good of the other forum users:

Alibre has its own import issues. I half expected it to not import the file incorrectly, regardless of format. That is entirely separate though from the issue of MoI taking several hours to export a file in the first place. When it comes to product design models are often highly detailed, there should then be no limitation on the complexity of the part. That would defeat the purpose of product design.

Hi Sebastian, in e-mail you mentioned that it did finally export out of MoI but only after letting it sit overnight.

So it appears to be not a crash or actual lock-up bug but a performance issue, my guess is that it probably has something to do with this particular situation of having a high number of trim curves contained within a single surface.

I'll investigate it, but I'm not sure yet when that will lead to a solution, it may take a variety of different tests and also some back and forth with the author of the I/O libraries that MoI actually uses to do the export. It's something that will need tuning in the library, not in MoI's own code directly.

So I probably won't have an answer for you right away on why the export from MoI for this model takes so long, but I will try to find out what is happening and if it can be improved though.

In the meantime some of the methods that I described above can probably help to get your work done now - try doing the holes in Alibre, or try using 3DM import into Alibre with the settings as I showed above.

- Michael

I got a surface with 3200 x 1.2mm holes, export without any problem in under a minute... there's clearly something wrong here !

Hi DesuDeus, is your one a solid with little tubes also joined to the holes or just an individual surface?

- Michael

Individual surface, that's why :)
There's the tubes also but not the backface !

But I'm pretty sure that I tried to export the whole solid and it worked but it was too high polycount so I decided to do it with surfaces.
At this time I was on an i7 920 @ 3.5ghz and with 6gb of memory. It's better to export a cube before with low angle settings like 20° then export the solid, so that your exporter is set to 20° and not 5° for example !