Revit parametric modeling

I have been trying to do more with Revit massing and parametric family creations. They are useful in creating custom objects that can be "stretched" in many different ways.

I managed to use them in some limited ways like building precast panels and custom steel shapes. I feel there are so much more I can do with these tools. There are books and tutorial materials on this subject but it seems they cover more on the theory parts, less on examples or applications. For example, the confusing concept of "constrain" within families (or I guess my lack of understanding of it) has been one of the sources of my frustrations.

I thought webcast or webinar would be much better since it would allow people to see live action and listen to instant comments.

After the scouring the internet and AUGI forums, I found a good webcast tutorial at design reform (http://designreform.net).

The tutorial covers basic and more advanced family creations, among other things. The company apparently provides consulting services to businesses who want to get better in integrating or implementing multiple softwares/ technologies into more efficient design platform. The founders used to work at SHoP Architects, a well known New York architectural firm.