FDF (Field Data File) Format

FDF (Field Data File) is a data file format to store finite element field data. An FDF file is a simple text file containing any scalar or vector field that is defined node by node or element by element or side by side. A user can either implement himself another procedure to read his finite element field data or develop a simple program to convert his favorite field file structure to an FDF file.

An FDF file contains a series of fields given either by nodes, elements or sides. Each field is identified by a time value (the fields correspond typically to different time steps in a transient calculation.

The main principle here is that any information in the file is contained in a line and is defined by a keyword following the rules :

Node-By-Node Field Files

• The first line must contain at the first columns the string #NODE_FIELD!
• All other lines contain keywords and other parameters separated by any number of spaces following FFI rules.
• An FDF file can contain any number of fields
• Keyword Name starts a line that gives a name to the given field. A string giving this name must follow.
• Keyword NbNodes starts a line that gives the number of nodes A string giving this name must follow.
• Keyword NbDOF starts a line that gives the (constant) number of degrees of freedom by node. An integer number must follow.
• Keyword Time starts a line that gives the time value for which the field is given after. A real number giving the time value must follow.
• Keyword Data starts a series of exactly NbNodes lines giving the field. Each line must have the following format :
  
  

  label	Label of node (integer)
  v[1]	First degree of freedom of field at given node (real number)
  ...	... ...
  v[nb_dof]	nb_dof-th degree of freedom of field at given node (real number)

• The last line of the FDF file must contain the keyword EOF (as End Of File).

Element-By-Element Field Files

• The first line must contain at the first columns the string #ELEMENT_FIELD!
• All other lines contain keywords and other parameters separated by any number of spaces following FFI rules.
• An FDF file can contain any number of fields
• Keyword Name starts a line that gives a name to the given field. A string giving this name must follow.
• Keyword NbElements starts a line that gives the number of elements A string giving this name must follow.
• Keyword NbDOF starts a line that gives the (constant) number of degrees of freedom by element. An integer number must follow.
• Keyword Time starts a line that gives the time value for which the field is given after. A real number giving the time value must follow.
• Keyword Data starts a series of exactly NbElements lines giving the field. Each line must have the following format :
  
  

  label	Label of element (integer)
  v[1]	First degree of freedom of field at given element (real number)
  ...	... ...
  v[nb_dof]	nb_dof-th degree of freedom of field at given element (real number)

• The last line of the FDF file must contain the keyword EOF (as End Of File).