Md2 loader Question ---about Geometry

There is a line of code:
objRoot.addChild(new Shape3D(array, app));

Where app == Application and
array == QuadArray

I understand that the Shape3D is being added to the scene graph but what is the QuadArray> and what does it do?

Any help is appreciated.
Thanks

Nevermind… I think I understand. This is the platform that the figure is standing on. If I am wrong please correct me.