Here is a very useful tool from Autodesk Labs to recognise parametric features from base solids or translated model.

I remember looking at an early version of feature recognition for MDT 6 back in 2002.

This gave the potential to recognise features automatically but in practice was quite limited

as you could not choose specific parts of the model to work on.

The latest offering from Autodesk Labs has taken this concept further by allowing many more advanced tools for selecting specific faces on the model to convert to features or a fully automated mode. In practice, it is better just to recognise the features that will need changing. In the fan example I just convert the holes, which takes just a few seconds. If you work with translated data or want to modify or rework some of your older 3D designs then this tool could prove to be a very useful addition to Autodesk Inventor.

http://labs.autodesk.com/utilities/feature_recognition/

Enjoy,

Lawrenceh