Extruding a STL mesh
 

Dear Friends,
Does anyone know how to extrude one face of a STL file in any of the geometry designing softwares? I have a STL file and would like to extrude one of its faces (which is a circular face) in the direction normal to the face.

I tried ICEM, but it needs a driving curve/vector and I dont know how to specify normal vector as the driving vector? Is it possible to find normal vector in ICEM? ICEM has also some other possibilities but it only extrude b-spline surfaces and STL files are faceted surfaces.

Is there any way in ICEM or any other software.

Best