Hello Jonathan and Steve
For all that have or had the "Recovering from invalid parameter values by cutting step size" problem, this does not necessarily stops the optimization but makes it sooooooo slowly that is a lot quicker do to some optimization "by hand" - meaning changing the values and do a own optimization based on what was obtained after each run.
This annoying problem was never fully solved by PTC in any WF Promechanica version.
I agree with Steve that Simulate (Creo) has improved (considerably) optimization speed.
It is quicker but not yet free of the "old problems". Sometimes it stuck in some parameters values (this means that iteration after iteration there is no change) but does not stop with “best value found”. Instead out of the blue it decides to run the simulation all again using the other algorithms - that like magic converges in a lot less iterations!!!
I also saw our old friend "Recovering from invalid parameter values" but in this case it was most likely a real construction geometry problem but it did not slowed down the optimization as before. And this is good!
In general I would agree that the easier solution would be to use optimization with Creo - what may be a bit unfair for those users that have to work with a previously Mechanica version that so far do not have yet a solution for this problem.
Best regards
Rodolfo