 Additional assembly of fibrils is guided by fibroblasts, which deposit fully formed fibrils from fibripositors.In the fibrillar collagens, molecules are staggered to adjacent molecules by about 67 nm (a unit that is referred to as ‘D’ and changes depending upon the hydration state of the aggregate).In each D-period repeat of the microfibril, there is a part containing five molecules in cross-section, called the “overlap”, and a part containing only four molecules, called the "gap".