Figure 1.

Schematic diagram of the components of entity handles and views. The molecular structure is represented as a tree-like structure rooted at the entity (E). The levels of the tree are formed by chain (C), residue (R) and atom (A). In green, an example entity view containing only a selected subset of elements is shown. The hierarchy of the entity view is separate from the handle; however, at every level the view maps back to its handle, giving access to its properties.