Hi Micha,

> (6) mesh #4
>
> Seems to be the same problem like at (4) and I don't understand it, why edges
> are independent from the surfaces

Well, edges are not restricted to only be along the natural boundary of a surface.

If they were, then you would be unable to trim surfaces in many situations.

Here is an example - say I start with this plane, it is a simple surface where it has 4 edges that are on the natural boundary of the surface:



Now if I take a curve made up of many different segments and trim that plane, it will create a bunch of new edges on that surface:



You can see there that I turned on control points for the surface as well, and the plane surface is still there underneath those 10 new edges that form the new boundary.

Similarly you can have any number of trim curves on a curved surface as well, and it is possible to have trim curves that touch each other smoothly rather than at a sharp corner - that is what was happening with this previous model, if you go in and try to select the outside edges of that cylinder you will see that you can select a small portion of it, which is actually one small edge itself, the boundary is made up of a number of small edges touching one another rather than one single large edge.

Check out this FAQ answer for some more illustrations on how trim curves and an "underlying surface" work:


A larger number of edges makes for a more complex topology and will prevent MoI from doing things like spacing points out evenly across a larger distance like it can do when the edges are larger.

So if you want the most optimal mesh result, it will help to have an optimized topology as well.

A complex topology will also tend to generate a more complex mesh result as well.

The mesh will still be valid on a non-optimized topology (as in no holes, etc...). But since you are very interested in getting the best possible mesh, you will need to also give the mesher clean topology to work with.

In general it is a pretty simple situation, I mean you can't expect the mesher to generate perfect results when it is given lower quality inputs. (sometimes low quality can mean different things, but I've described previously the types of alignment conditions which help for this purpose of all quad generation).

There's a saying: "Garbage in, garbage out", - if you don't start with a high quality result it is not realistic to expect the highest quality result out the other end!


> and how to delete edges.

In MoI this can be done by selecting all the edges of a single surface (not a joined surface, use Edit/Separate) and pushing delete. Check out this object repair tutorial for more info:
http://moi3d.com/forum/index.php?webtag=MOI&msg=446.17


> I would like to
> avoid the effect per Rhino script befor I export the object to MOI. I afraid, at
> complex models the "separate-edge-delete-join" method could be a problem.

Yes, it can definitely be difficult to do a cleanup of messy stuff on a complex model!

But if you don't provide clean inputs, it is just not possible to get the very best quality outputs.

Keep in mind that MoI does not have the same level of human judgment and analysis that you can apply, it is a very difficult problem to do a fully automatic cleanup without judgement to assist the process.

- Michael