There is a new concept in AX 2012 called model. Model is a container of metadata elements, like AOT objects, sources, label files, etc. The main benefit of models is the possibility to easily export and import them from\to AX. This means that model is a very convenient deployment mechanism – you can develop your feature in a separate model, export it and then deploy to production environment or distribute it to your customers.
New command line tool AxUtil.exe is shipped together with AX 2012 and allows to perform operations with models in a very easy way.
AX development workspace supports models very well. It is possible to see to which model any AOT element belongs to, move AOT elements between models, create project from model, etc. AX version control system integration has model support as well. For example, it is possible to store xpos for different models in different folders in the file system.
You can read more about models in the great series of posts by mfp:
AX models – Part 1 – Deploying models
AX models – Part 2 – Manifest and signing
AX models – Part 3 – Multiple models per layer
AX models – Part 4 – Working with models inside MorphX