To get an idea of the size of the objects in the scene, we can add a simple visual grid.
In this tutorial, we added the component OglGrid. It display a simple grid on a chosen plane. By default, the grid is displayed on the plane xy. If we know the size of the grid (10 units in the example), we can have a visual hint on the size of the liver. It also gives the orientation of the liver compared to the grid.