Object Space
The coordinate space in which the vertices of a mesh are specified is called the object space. When preparing meshes for use in vvvv it makes sense to think about the object-spaces dimensions. If you need realistic scaling from between different meshes you'd best think of one unit in object space being equal to 1 meter in real life.
Otherwise if you're just dealing with a bunch of objects that need no special size it's often useful to keep their vertices within a 1 unit cube.