Creo Simulate > Running Solvers > FEM Solvers > Determining a Run Method > Outputting to a User-Defined Solver
  
Outputting to a User-Defined Solver
If a solver can accept input and generate output in the FEM Neutral Format, you can use it to solve a model. You can include the name of the desired solver in the Solver option menu by setting the pro_solver_name configuration option. To enable the solver, you need to specify the path to the solver executable by setting the pro_solver_path configuration option.
A user solver should work as follows:
path_to_solver_executable input_file output_file
where:
input_file—input file in the FEM Neutral format with the extension .fnf.
output_file—solution results file in the FEM Neutral format with the extension .fnf
For example:
/abc/def/fea_solver model.fnf model_res.fnf
If it finds a solution, the user solver should return a zero value upon termination.