<%= form_for @plan do |form| %> <%= form.fields_for :routines do |routine| %> <% if routine.object.id == @routine.id %> <%= routine.fields_for :routine_workouts do |rw| %> <%= render "plans/routines/workout_fields", child: rw, routine_id: @routine.id %> <% end %> <% end %> <% end %> <% end %>