Hi Jörg,

> Can you explain how you solved the problem?

I used "untrim" to erase the trimming boundaries on those pieces and that then recovers the full original underlying surface, I then retrimmed them with your curves to make a better quality trimming boundary.

There's a short description of untrim here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=444.4

And there's a longer tutorial on these kinds of object repair techniques here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=446.17


> How do you get away the unnecessary cuts / edges
> without having to re-engineer all need?
> I can look at the file, but do not the way to solve the problem.

There were some areas where there were several cut up pieces that were actually parts of the same original surface. When 2 surfaces come from the same exact underlying surface you can use boolean union on them and it will be able to eliminate any in-between edges in that case, it can also heal (remove) edges between 2 co-planar planes in the same way.

So to clean those up I used Edit > Separate on your model to break it into individual surfaces, then picked 2 of those fragments at a time and then did boolean union on the 2 fragments to get a result without any interior edges.


> New cuts are set through trimming?

Yes, after an "untrim" to get rid of the badly formed boundaries then I used Trim after that to cut it to a cleaner new boundary. At one point I took one of your longer curves and flattened it down to 2D to use as part of the trimming boundary.


> My approach is this: I Separate the parts from each other, then create the curves from
> the edge selections. I use for lofts or sweeps.
> I'm not sure whether this is the right way.

This is how I formed the actual surfaces - however you need to have clean trim boundaries in order to use this technique - things like little tiny weird edge fragments like you had before will lead to problems.

Once I got all the edges set up cleanly I picked 2 edges at a time and did a Construct > Loft to build the surface between them, then those pieces were joined to the other ones.


> The edges of your model are continuous! How did the surfaces have created?

In some areas I used the Merge command to merge together a bunch of fragmented edge segments into longer edge pieces:
http://moi3d.com/2.0/docs/moi_command_reference10.htm#merge


But it's actually best to try and avoid needing to do these kinds of repairs in the first place, if possible you want to get the model constructed out of somewhat more simple and cleanly meeting pieces from the earliest stages.

- Michael