Extension of Transactional Fiori App using Business Application Studio

Hi Experts,

I don't find any option to extend transactional fiori apps by creating an extension project in BAS like we had in sap WebIde full stack. The only option i see for extension is adaptation project.

Could you please suggest on this. Are we using adaptation project only for normal extensions of view and controllers *like view replacement * controller replacements.

Thanks,

Rakesh