Method 1 - The Short Way

  CRhinoCommand::result CCommandTest::RunCommand( const CRhinoCommandContext& context )
  {
    CRhinoGetObject go;
    go.SetCommandPrompt( L"Select brep" );
    go.SetGeometryFilter( ON::brep_object );
    go.GetObjects(1,1);
    if( go.CommandResult() != success )
      return go.CommandResult();


    CRhinoObjRef ref = go.Object(0);


    // Simple translation transformation
    ON_Xform xform;
    xform.Translation( ON_3dVector(18,-18,-25) );


    context.m_doc.TransformObject( ref, xform );
    context.m_doc.Redraw();


    return success;
  }

Method 2 - The Long Way

  CRhinoCommand::result CCommandTest::RunCommand( const CRhinoCommandContext& context )
  {
    CRhinoGetObject go; 
    go.SetCommandPrompt( L"Select brep" ); 
    go.SetGeometryFilter( ON::brep_object ); 
    go.GetObjects(1,1);
    if( go.CommandResult() != success )
      return go.CommandResult();


    const CRhinoObjRef& ref = go.Object(0);
    const CRhinoObject* obj = ref.Object();
    if( !obj )
      return failure;
    const ON_Brep* brep = ref.Brep();
    if( !brep )
      return failure;
    ON_Brep* dupe = brep->Duplicate();
    if( !dupe )
      return failure;


    // Simple translation transformation
    ON_Xform xform;
    xform.Translation( ON_3dVector(18,-18,-25) );


    if( !dupe->Transform( xform ) )
    {
      RhinoApp().Print( L"Unable to transform object.\n" );
      delete dupe;
      return failure;
    }


    ON_3dmObjectAttributes attribs = obj->Attributes();
    context.m_doc.AddBrepObject( *dupe, &attribs );


    // Since CRhinoDoc::AddBrepObject() make a copy of the input
    // brep, we are responsible for deleting the original. Otherwise
    // we will leak memory;
    delete dupe;
    // Delete the selected object
    context.m_doc.DeleteObject( ref );
    context.m_doc.Redraw();
    return success;
  }

VB.NET (Rhino 4)

Method 1 - The Short Way

  Public Overrides Function RunCommand(ByVal context As IRhinoCommandContext) _
    As IRhinoCommand.result
    Dim go As New MRhinoGetObject()
    go.SetCommandPrompt("Select brep")
    go.SetGeometryFilter(IRhinoGetObject.GEOMETRY_TYPE_FILTER.polysrf_object _
                      Or IRhinoGetObject.GEOMETRY_TYPE_FILTER.surface_object)
    go.GetObjects(1, 1)
    If (go.CommandResult() <> IRhinoCommand.result.success) Then
      Return go.CommandResult()
    End If
    ' Simple translation transformation
    Dim xform As New OnXform()
    xform.Translation(18, -18, -25)
    Dim objref As MRhinoObjRef = go.Object(0)
    context.m_doc.TransformObject(objref, xform)
    context.m_doc.Redraw()
    Return IRhinoCommand.result.success
  End Function

Method 2 - The Long Way

  Public Overrides Function RunCommand(ByVal context As IRhinoCommandContext) _
    As IRhinoCommand.result
    Dim go As New MRhinoGetObject()
    go.SetCommandPrompt("Select brep")
    go.SetGeometryFilter(IRhinoGetObject.GEOMETRY_TYPE_FILTER.polysrf_object Or _
                         IRhinoGetObject.GEOMETRY_TYPE_FILTER.surface_object)
    go.GetObjects(1, 1)
    If (go.CommandResult() <> IRhinoCommand.result.success) Then
      Return go.CommandResult()
    End If


    Dim objref As MRhinoObjRef = go.Object(0)
    Dim obj As IRhinoObject = objref.Object()
    If (obj Is Nothing) Then Return IRhinoCommand.result.failure
    Dim brep As IOnBrep = objref.Brep()
    If (brep Is Nothing) Then Return IRhinoCommand.result.failure
    Dim dupe As New OnBrep(brep)


    ' Simple translation transformation
    Dim xform As New OnXform()
    xform.Translation(18, -18, -25)
    If (Not dupe.Transform(xform)) Then
      RhUtil.RhinoApp().Print("Unable to transform object." + vbCrLf)
      Return IRhinoCommand.result.failure
    End If


    Dim attribs As IOn3dmObjectAttributes = obj.Attributes()
    context.m_doc.AddBrepObject(dupe, attribs)


    ' Delete the selected object
    context.m_doc.DeleteObject(objref)
    context.m_doc.Redraw()
    Return IRhinoCommand.result.success
  End Function

C# (Rhino 4)

Method 1 - The Short Way

  public override IRhinoCommand.result RunCommand(IRhinoCommandContext context)
  {
    MRhinoGetObject go = new MRhinoGetObject();
    go.SetCommandPrompt("Select brep");
    go.SetGeometryFilter(IRhinoGetObject.GEOMETRY_TYPE_FILTER.polysrf_object
                       | IRhinoGetObject.GEOMETRY_TYPE_FILTER.surface_object);
    go.GetObjects(1, 1);
    if(go.CommandResult() != IRhinoCommand.result.success)
      return go.CommandResult();
    // Simple translation transformation
    OnXform xform = new OnXform();
    xform.Translation(18, -18, -25);
    MRhinoObjRef objref = go.Object(0);
    context.m_doc.TransformObject(ref objref, xform);
    context.m_doc.Redraw();
    return IRhinoCommand.result.success;
  }

Method 2 - The Long Way

  public override IRhinoCommand.result RunCommand(IRhinoCommandContext context)
  {
    MRhinoGetObject go = new MRhinoGetObject();
    go.SetCommandPrompt("Select brep");
    go.SetGeometryFilter(IRhinoGetObject.GEOMETRY_TYPE_FILTER.polysrf_object
                       | IRhinoGetObject.GEOMETRY_TYPE_FILTER.surface_object);
    go.GetObjects(1, 1);
    if(go.CommandResult() != IRhinoCommand.result.success)
      return go.CommandResult();


    MRhinoObjRef objref = go.Object(0);
    IRhinoObject obj = objref.Object();
    if(obj == null)
      return IRhinoCommand.result.failure;
    IOnBrep brep = objref.Brep();
    if(brep == null)
      return IRhinoCommand.result.failure;
    OnBrep dupe = new OnBrep(brep);


    // Simple translation transformation
    OnXform xform = new OnXform();
    xform.Translation(18, -18, -25);
    if(!dupe.Transform(xform))
    {
      RhUtil.RhinoApp().Print("Unable to transform object.\n");
      return IRhinoCommand.result.failure;
    }


    IOn3dmObjectAttributes attribs = obj.Attributes();
    context.m_doc.AddBrepObject(dupe, attribs);


    // Delete the selected object
    context.m_doc.DeleteObject(objref);
    context.m_doc.Redraw();
    return IRhinoCommand.result.success;
  }