Import own formats with asset importer

Hi! I would like to import my own formats. These are to then emerge also in the Project folder and also the characteristics them have to point out. For example Xpresso tags or simply only dependence of each other. I have already tried with the function AssetDatabase.AddObjectToAsset () to get ahead. however unsuccessfully. Can someone help me? Thanks a lot.

Look at the OBJ importer examples in the script wiki and asset store for importing. You can make custom Editor classes to help your stuff probably.