Use this tab window to define the functions of
  parts.
  The engineering function structure is a conceptual level of product construction.
  Functions can be arranged in a structure. Each function on the bottom level can also
  have parts and the corresponding part structures attached.  The purpose is to organize
  the product structure so that it is familiar to multiple disciplines and to help with
  the construction of a product without having to immediately decide all its properties. 
A function is the intended use of connected part(s). One
  part can be connected to more than one function, i.e., it can have several
  functions in the product structure. A function must be defined here
  before it can be used in other places.
BDR For Design Standard Product
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