Once you have generated the mesh, and assigned the conditions and the materials properties, as well as the general problem and intervals data for the solver, it is necessary to produce the data input files to be processed by that program.
To manage this reading, GiD is able to interpret a file called problem_type_name.bas (where problem_type_name is the name of the working directory of the problem type without the .bas extension).
This file (template file) describes the format and structure of the required data input file for the solver that is used for a particular case. This file must remain in the problem_type_name.gid directory, as well as the other files already described - problem_type_name.cnd, problem_type_name.mat, problem_type_name.prb and also problem_type_name.sim and ***.geo, if desired.
In the case that more than one data input file is needed, GiD allows the creation of more files by means of additional ***.bas files (note that while problem_type_name.bas creates a data input file named project_name.dat, successive ***.bas files - where *** can be any name - create files with the names project_name-1.dat, project_name-2.dat, and so on). The new files follow the same rules as the ones explained next for problem_type_name.bas files.
These files work as an interface from GiD's standard results to the specific data input for any individual solver module. This means that the process of running the analysis simply forms another step that can be completed within the system.
In the event of an error in the preparation of the data input files, the programmer has only to fix the corresponding problem_type_name.bas or ***.bas file and rerun the example, without needing to leave GiD, recompile or reassign any data or re-mesh.
This facility is due to the structure of the template files. They are a group of macros (like an ordinary programming language) that can be read, without the need of a compiler, every time the corresponding analysis file is to be written. This ensures a fast way to debug mistakes.