Hi Ironice - you can use the Flip command in MoI to flip an object, some more info here:
http://moi3d.com/2.0/docs/moi_command_reference10.htm#flip

> And this, if i invert the object in SI, it looks like this. Other
> objects with the right normals looks much better and there
> is no dark triangles.

That looks like Softimage is discarding the imported vertex normals when you do the flip - you may want to report that as a bug to Autodesk because instead of doing that it should just simply flip the vertex normals as well rather than discarding them and recalculating new ones from the polygon faces.

Mechanical type models don't work very well with automatic vertex normals where the normals are just computed as an average of all surrounding faces, it usually works a lot better to have the vertex normals from the original CAD model to be used.

- Michael

Hi Ironice, also actually the easiest thing to do is to just turn on double-sided lighting in your rendering settings, and that way it won't make any difference when you go to render the object which way the vertex normals happen to be pointing.

One other thing - if you can get your object to be a solid that has a completely connected skin then that will automatically get its vertex normals oriented to point to the outside of the solid volume. If you have an open surface object then the positive surface normal direction is arbitrary.

But if you use 2-sided lighting in your rendering, it doesn't matter which way is the positive direction anyway.

- Michael

Thank you very, very much Michael.

Flip was the solution.
It looks now great. :)