Hi Mik (MIKULAS) and Pilou,

and thanks a lot for your suggestions.

Yea...I already knew all this products : MeshMixer, NeoBarok, etc...etc...
and I currently, often or occasionally, use all of them.

But I think that all those products, although they are with no doubt very powerful and very useful for some "exotic" or particular situations,
they can't be used for "standard" Poly/SDS modelling.
They can be rather a good companion to couple with a main modelling software.

For example i also use the fantastic MagicaVoxel (https://voxel.codeplex.com/), but it could never be my main modelling package...

Anyway, thanks to all.

Ciao.

- Marco (mkdm)