Hi Larry, yes MoI v4 is now a 64-bit program and so can use all your system memory instead of running into 32-bit limits. So it can handle much larger files than v3.

Also there have been some other improvements such as using multiple CPU cores for processing objects so usually it's a lot faster loading files too.

There is a collection of all the V4 beta release notes at http://moi3d.com/wiki/V4Beta.

However, CAD file translation is a very complex area, the thing that tends to cause the most problems is that different CAD systems represent trim boundaries in somewhat different ways particularly on closed surfaces and so that means there can be some processing needed on trim boundaries at import time. It's a somewhat fragile area and when you see the type of distortions you mention it means something didn't go quite right with that. This can usually be corrected by doing some repair operations like untrimming and retrimming the messed up surface. There is a tutorial on these techniques at http://moi3d.com/forum/index.php?webtag=MOI&msg=446.17 .

Your propeller.stp model has the same issue in v4 as in v3. Unfortunately because it is a delicate area and we are at the very end of the v4 beta time period, it is not an area that I feel comfortable with making changes to because of the risk of introducing other bugs. It is an area that I would like to tune up in the future but it will have to happen earlier in a release cycle rather than at the end.

What happens with propeller.stp if you use IGES format instead of STEP/SAT ? If your software has an option for using IGES type 144 surfaces that could potentially have a trim boundary closer to what MoI needs and so might have less processing needed on it.

re: mould.quadlobe.toy.stp - the same plug problem is happening with v4 here as well. V4 does now import all the colors. If you delete that square plug you can then show naked edges (http://moi3d.com/forum/index.php?webtag=MOI&msg=6051.2) to see where it was supposed to be. There is a very skinny ring there, only 0.0017 units wide. That can generally cause problems having such a small width. But if you select the object you can then use Construct > Planar to fill it in and then it all seems to be ok after that.

re:
> 2. Can I install MOI 4.0 alongside and separate from MOI 3.0 and not have it interfere with MOI 3.0 in any way,
> including not overwriting or changing MOI 3.0's configuration file?

By default they will install to separate directories but they will use the same moi.ini file. But there isn't any problem with them using the same moi.ini file, v4 will add some more entries to it for new things in v4 but those are just ignored by v3. It is possible to make v4 use a separate moi.ini file, you can do that by either putting a moi.ini file in the same folder as moi.exe, then it will use that one. You'll need to make v4 run with administrator privileges for it to be able to write to the file though. Or another thing is if you pass a path to a moi.ini file (put " " around it if there are any spaces in the path), it will then use that ini file.

re:
> Otherwise I'd rather not switch to MOI 4.0 until the release version. I have the thread limit set to 1 and
> the undo levels to 0 to save memory so as to be able to import and export more complex models and meshes.

Moi v4 is far, far better at dealing with complex models so if that's an area you're working with I would definitely recommend using v4 now instead of v3. There are improvements in a lot of areas for this - no 32-bit memory limit, multi core object processing on load, a file progress indicator on load rather than everything just freezing until it's done, and improvements in the display engine.


re:
> 3. When exporting to .obj, without choosing to weld vertices, MOI 3.0 sometimes introduces unnecessary
> vertex duplication / seams.

If I understand you correctly those seams are in spots where a surface has a hole in it. Most polygon mesh formats do not have the concept in them of a polygon with an internal hole in it, so when there is a hole in a surface after it has been subdivided, the polygon will be divided through the hole so as to bridge the outer and interior loop so it can be represented by a regular polygon instead of a polygon with an internal hole "island".


> 5. What will be the upgrade price to MOI 4.0 for MOI 3.0 customers?

The upgrade price is $100 between versions, although if you ordered MoI v3 within the past 8 or 9 months or so you will be able to get a free upgrade.


> 6. Any ETA on the release version of MOI 4.0 and the release version of MOI 5.0 ?

I don't have a specific date yet, there will still be one more v4 beta release before the final one. I don't have any idea yet when v5 will be released. It should not be anywhere as long as the gap between v3 and v4 though which has been from a major rewrite undertaken for v4 to get it to be 64-bit and also a Mac native build.

Thanks, - Michael