do you need to get how much time each user spend on creating his drawings? or do you want to calculate how many drawing were created by each user? or something else&
To control and manage the time used per drawing since it is crated some pml functions must be put behind the draft module. That would be the best and most reliable way to manage. Functions should write some log files or do some simple time calculations. Other not so reliable way is to check sessions and elements in them. I would choose first solution if I would have been on your place.