Hi, This thread is for discussing the design of the value.write user function to handle outputting the spin.model variable values. This was brought up as part of the thread: http://thread.gmane.org/gmane.science.nmr.relax.devel/4372/focus=4585 It should be possible to modify the value.write user function to handle the model. The user function call should look like: value.write(param='model', file=... It would be best to set up a dedicated system test for this. It could consist of two lines - simply loading the relax state at test_suite/shared_data/dispersion/KTeilum_FMPoulsen_MAkke_2006/acbp_cpmg_disp_101MGuHCl_40C_041223/relax_results_trunc/final_state.bz2, and then running the value.write user function. For the implementation, in the relax prompt, type: relax> help(value.write) In the parameter tables for the analysis types, 'model' could be added for the dispersion analysis. It may then be possible to add 'model' to self.PARAMS in the specific_analyses.relax_disp.api.Relax_disp.__init__() method. That might be sufficient to implement this and allow the system test to pass. Regards, Edward