Hi Jacobo, thanks for reporting these additional issues!
It turns out that new cracking is a bad side effect from doing the scaling.
There is a slight gap between the surfaces in that area. When scaling up, it increases the size of the gap to be large enough so that it will not join. MoI will only attempt to join together edges that pretty close together - within a maximum of 0.005 units.
If you look at that joined object in the normal viewport (not the mesh export display), if you look closely you can notice that the edges there are a bit darker than normal - this is because there are actually 2 edges there right next to one another since they did not get joined to one common edge. When 2 edges are drawn over top of one another they will appear slightly darker than normal.
However, I think that I've actually found a way to fix the original problem with join so that scaling will not be required.
I've made a patch for you here:
http://moi3d.com/beta/join_patch.zip to install the patch, unzip the moi_lib.dll file and copy it over top of the old one in c:\Program Files\MoI beta Aug-1-2007 .
I have not tested every part of your model yet, but it looks like this should enable join to work properly without doing the scaling trick, so it should handle all areas properly now including the one that was broken by doing scaling.
Can you please give that one a try and see if you can get proper results without scaling now?
> I always get this kind of discontinuity in the number of
> segments in some rounded surfaces. I was wondering if there would be
> a way to get rid of that.
This can happen in areas where there is a change in curvature. That surface that you show there is curved with a slightly smaller radius (more tightly curved) near the middle than near the ends. The mesher tests each quad to see if it is within the angular tolerance - those ones that got additional subdivision were not within angular tolerance so they got subdivided more.
It's going to be a difficult thing to get rid of without also reducing detail too much in more irregular curved shapes. This kind of refinement helps create details in surfaces with smaller tightly curved bits in them. Maybe I can include an option in the future to disable this kind of refinement, I'll have to think about that one a bit and what kind of negative side effects that could cause.
You can turn the angle down and try to use "Divide larger than" or aspect ratio controls to try and more evenly divide things up instead of the angular test.
- Michael