Andrew,
that depends on a type of your project you are working on. All is pretty much locked to BCA. Class 1 and 10 buildings require BASIX however check for all specifics in regards to states and territories. Class 2 to 9 requires Section J (in BCA) that needs to be addressed.
First one (BASIX) you just go to the website and follow the guidelines... it is a pretty much straightforward procedure.
Second one (Section J) is more difficult because it is really hard to meet deem-to-satisfy requirements. In other words all parts of the structure must meet BCA requirements but that practically means you would be able to build a wool shed or similar simple structure at most. However it allows for a compliance based on ESD modelling.
My experience is to get ESD fellas on board and liaise with them (in regards to AC data in/out) because the tricky part is they all use bespoke software to do their mambo-jumbo.
Personally I would not do those calculations by my self (as an architect) to simply avoid any PI issues as they can be great.
Anyway as far as I know ESD needs a greatly simplified model. The most recent project proved that ESD consultant was quicker to actually model his own model than importing and cleaning down our model exported from AC.
Unfortunately I cannot remember any of software names used for ESD thing at all but any of ESD consultants would give you some software options.
::rk