How about:
ITriObject triObj = (ITriObject)myNode.EvalWorldState( 0, true ).Obj.ConvertToType( 0, TriObjClassID );
IMesh mesh = triObj.Mesh;
int faceIndex = mesh.IntersectRay( myRay, rayPoisition, normal );
Marsel Khadiyev (Software Developer, EPHERE Inc.)