If you don't want to use *.arx and preview curves on 3DSOLID, then you could try command SURFEXTRACTCURVE and watch I suppose LWPOLYLINES/SPLINES on which I suppose you need to pick point... There are 2 directions, so you could create both directions and finally use OSNAP "int" - intersection... But to get 3DSOLID, you'll need Rhino, I don't know other way around this - non uniformly scaled 3DSOLID/SURFACE blocks... And AutoDesk wasn't interested in making this feature - it is long time issue, though it was related only for 3DSOLIDS/SURFACES - I mean EXPLODE-ing block that contains them...