How to make boundary curves from mesh objects?

[bsideB]

Hi everybody,

I need to find an easy way to make a boundary or a silhouette curve of STL/mesh bodies.

I use that curve as a limit for machining.
Actually I make an sketch using splines and afterwards I offset that curve and extrude it to generate de machining stock, but this costs me lot of time.

I've tried to make it automatically using "Insert->Curve from bodies->Extract Curves->Shadow OutLine" but it always asks me to set the "Hide Invisible Lines" view, even when is activated.

Any idea?

Thanks,
Dani.