I own TuboCAD Pro and have some 3D models that I would like to get into Lightwave 3D. TurboCAD can save to IGS, but there is a plugin to save to 3DM that I do not yet own. Is there any advantages to saving to 3DM over IGS for use with MoI?

Hi Drakon, re: IGS versus 3DM

Typically IGES format only contains individual surfaces instead of solids, similar to if your model had been separated or "exploded" into individual surface sheets that are not glued to one another along their edges anymore.

So when MoI reads in an IGES file, it will go through a joining process where it glues those surfaces together to form a solid again.

That joining process is not likely to be needed with 3DM format, because 3DM is more likely to have fully joined solids stored in it rather than individual surfaces stored within the file.

So there is some advantage to 3DM over IGES since the 3DM import will involve one less mechanism being applied to it at import time into MoI. That joining procedure can get to be fairly time consuming on highly complex models.

But unless your models are of a significantly high complexity it is not likely to be a big issue.

So I would think that probably just using your current IGS export should be fine.

- Michael

Thanks Michael. I have already spent a lot of money on software this past year trying to make 3D mechanical models for animation. So far all I have to show for it are CAD models that I cannot get out of TurboCAD in a usable format for Carrara or Lightwave. Looks like MoI is what I have been looking for all this time.

Hi Drakon, yup MoI should work well for that!

I think for Carrara you would want to use OBJ format export from MoI, and MoI also supports LWO export for going to LightWave.

You should be able to give it a try with the MoI trial version from here:
http://moi3d.com/download.htm

Just open your IGES file, and then do a "Save As" using OBJ or LWO...

- Michael

Just to second that...IGS is really tedious to work with. Export to STP/STEP or if you can get something to port it straight to 3DM would be worth it IMHO.

If your working with single parts IGES it might not be too bad, the issue really gets nasty when your dealing with assemblies with tight tolerance parts (and the surfaces get joined to the wrong parts creating a nightmare).

If you are dealing with assemblies and your stuck with IGES - a little work around you might want to check to see if you can export the assembly as individual files part files. You can then import the individual parts and edited as needed so they are clean. Then see if you can tinker with some scripting options to import the "set" into a single assembly file (Michael might want to verify if you can script the files in batch but I seem to remember something about some batch processing scripts). Just a little work-around I had come up with back when dealing with Unigraphic and Rhino (before Pro-E and STEP finally arrived at the workplace) :D

Cheers!
AW

Hi Michael,

is there a way for you for coding to identify which surfaces are part of an original polysurface? Joining the wrong surfaces is a big disadvantage of IGES. Last I got a CAD model by a client, a desin concept with interleaved parts. The parts was stuck into each over without gaps, so surfaces was coplanar and an IGES import caused wrong conections - a worst case for IGES.

-Micha

Hi Micha,

> is there a way for you for coding to identify which surfaces
> are part of an original polysurface?

No, not in all cases. But it is possible to have this information come through properly.

If the IGES file was created with a different "level" (basically the equivalent of a layer in an IGES file) for each part, then there should not be any problem because MoI will only try to join together surfaces that belong to the same level. That was a new function for MoI v2, I added it in for one of the earliest v2 beta releases.

If you have a file that contains number of parts that touch each other at some common edges, and you have no other way to separate them (either by breaking into separate files, or by having parts in separate levels), then you'll need to turn off automatic joining (Options > Import/Export > IGES options > Join surfaces on import) and select the proper pieces manually and join them.

- Michael

Great, thank you for the little extra function and the reply. Good to know. :)