Embedded a qwt3d example into my project

[Make it GREAT again]

Hello, guys.
I want to embedded an example (mesh) of qwt3d into my project. The example has its own UI which should be placed somewhere onto the UI of my project. I tried moving its source files to my project and prompt the class of my project to parent level. But it seems not the correct way to go.

My project is simply this
#ifndef TESTGUI_H
#define TESTGUI_H

#include "meshmainwindow.h"
#include <QMainWindow>

namespace Ui {
class TestGui;
}

class TestGui : public QMainWindow
{
Q_OBJECT

public:
explicit TestGui(QWidget *parent = 0);
~TestGui();

private:
Ui::TestGui *ui;
};

#endif // TESTGUI_H

Mesh looks like this
#include "ui_meshmainwindowbase.h"

class QLabel;
class QTimer;
class QAction;
class QFileDialog;
class LightingDlg;
class ColorMapPreview;

class MeshMainWindow : public QMainWindow, protected Ui::MainWindow
{
Q_OBJECT
public:
MeshMainWindow( QWidget* parent = 0 );
~MeshMainWindow();

Qwt3D::GridPlot* dataWidget;

public slots: