The Convert to Mesh command converts any extrude, multiple extrude, sweep, subdivision, or wireframe object into a mesh object. Use the Object Info palette to edit the mesh object vertices. The command can also collect a number of separate 3D polygons into a single mesh object.
A mesh object can contain up to 30,000 vertices.
To convert to mesh:
Select the 3D object to convert.
Select Modify > Convert > Convert to Mesh.
The object changes to a mesh object. To edit the mesh, select Modify > Edit Group and edit the 3D polygons that make up the mesh.