The Geo COMP holds the geometry to be rendered. It references the material to be used for rendering, has transform controls, and allows instancing. We don't need to build our SOP networks in there; we can also just send our final geometry in one of these via an In SOP. Also, sometimes, it's useful to have the material that is to be used inside the Geo COMP, to be referenced via ./phjong1, for example. A Geo COMP can hold other Geo COMPs, which is especially useful since we can only assign one single material to a particular Geo COMP for rendering (although it can contain many MATs). An example of what can be achieved by this technique is the wheel asset that is located at /project1/advanced/wheelAsset, which is a more advanced example; but still, take a look at it for a second to get a more clear idea of the structure.

The Geo COMP might seem pretty useless at first glance, for example, its transform controls. Why not just put down a Transform SOP if we want to move things around...