Voila, here's a correction of the gear.
I have tried a little render test and I definitively have to change my workflow. Every edges are filleted, and I just can't move around my object anymore because it's way to heavy.
Takes 10 minutes to meshing the object for a 500.000 polys .obj output. (on a xeon quad 3.2)



IT would be really cool to find a smart way to handle more complex model like this. I suppose layers is a solution ... but even with layers it seems that all in all nurbs require more computer power than I though.

It's more easy to handle this amount of details with subdivision polygon method. You just handle the cage object, and subdivide it only for the rendering.

Here I have reduced the details in the MoI viewport, using something like 80° for the mesh angle, and remove the 'add details to inflection' of course. But it's still unworkable ... it takes age to do a mirror or a simple move.

Maybe a solution will be to able to store the fillets in an history stack, so you can choose to hide/show them when needed ...