Chris Price has been pushing the limits. Check it out:
“What I found was Revit would crash at around 580 conditional statements in a single formula… Surely Autodesk should know someone would try and do this, lol!
So how to get around this limitation, my first thought was to try and use “And” and “OR” conditions to try and reduce the number of required conditions. However, this was going to be extremely tedious and there would still be 168+… So then I decided to simply split across a couple of parameters. EG: I had 500 conditions in one parameter then linked to a different parameter with the remaining conditions. SOLVED!
I did note a large performance hit when changing parameters in the family editor. Changing any values would take 5-15 seconds. However, testing in a project and the changes are instant! So not sure why performance is fine in a project.”