Oh, that's much to read. :) Thank you for the answers.

First - why I'm fighting with the low poly count? I offer 3D visualisation and get my models from my clients. So, often I can't choose, how detailed the models are. Some production models, most from software like ProE, are so complex, that I must try to get the lowest possible polycount. For example if a designer send me a train seat and like to see a coach full of this seats, best rendered in very high res and without visible tessalation at 100% at the screen - worst case.
So my tests go in the direction low poly count and best quality. I happy to see that MoI doe's a great job for that.

Thank you PaQ for the 'avoid smaller than' hint. That's a good polycount saver. :)

Michael, I see, if I like to get a perfect mesh, than best I model at MoI. ;)

Now I better understand the concept of curves and trimmed surfaces. Thank you for the deatiled infos.

>> Two other things to this - at Rhino I found, that some triangles can be converted
>> to quads (maybe this is fixed in your internal version like you wrote at (9))
>This was with the Mesh#6.3dm model? Was this instance where you could convert some triangles to quads happening at the default mesh >parameters, or only at a particular parameter?
>If you can tell me the parameters you used to run into that, I can test with it over here and see if it is fixed by the other fix or not.

(Rhino "o" model - Mesh#6.3dm)
33° -> "96 triangles were converted into 48 quads."
22° -> "226 triangles were converted into 113 quads."

>> and could it be possible, that the CentroidTriangulation option is
>> part of the general meshing parameters?
>Is it something that you expect to be turning on or off very often?

I don't know - if I mesh an object, than I look at the preview and if I see a problem, than I change the parameter to get a better result. So, best would be good to get all control at one place.

Thanks,
Micha