Staad pro should have an option to model each and every type of staircase like single flight (straight)stairs,dog ledged strair, spiral stair, U shape stairs,L shape stairs,winder, double winder, 2 quarter winder, 2 quarter landing,curved staircase, circular staircase, combined staircase,Z staircase etc.so that modelling time for staircase is reduced and better analysis results obtained....
Moreover these staircases should be designed in either in RCDC or RCDC FE or any else....
Thank you for posting your idea. However whilst an interesting proposal, this is really not a capability that would suite a generic analysis and design application, but you are looking for a specialist staircase solution. I would suggest that you should consider the logic in defining the model and using the macro tool to create these to your requirements.