Stress Output

We can output nominal ( engg ) and logarithmic ( true) strain but I recently realized that there is no such distinction between true and engineering stress. Say I include material plasticity, are the stress I am looking at e.g vonmises, principal or components, are they wrt true stress or are they engineering. I tried searching but couldn't find it. I also haven't studied the FEM theory related to plastic analysis and stress/strain measures ( apparently there are different types such as piola stress, green strain etc. which I am starting to study ) Any pointers are appreciated.

Thanks.