Exporting mols in 3D graphical formats



I wold like to know a easy way to manipulate molecules (expecially
 proteins with ribbons, and so on...) in 3d commercial graphical packages
 (i.e. 3D-Studio). I already tried to export structures as VRML, but
 often they are too big to manage (~15Mb)
 If someone knows some script, o coverting utility, please help me!
 Thanks
 Stefano
 *********************************
 Forli Stefano
 Dip. Farmaco Chimico Tecnologico
 Universita' degli Studi di Siena
 Via Aldo Moro
 I-53100 Siena, Italy
 Phone: ++39 0577 234307
 Fax: ++39 0577 234333
 *********************************