Revit MEP - Should we model the Existing?

These are my favorite types of posts... The posts in which my readers get to comment and add all their input to drive the subject.  So please, comment your little hearts out!

We are starting a very large project at my firm and, of course, using Revit.  All disciplines are in house (MEP and Structural).  As I am on the Architecture side of things I am modeling the existing building as I type this post.  In a meeting last week the topic was introduced about do we or do we not model the Existing MEP...

The project will have many construction phases with the existing MEP systems being used during the first one or two major phases.  Then, depending on what the engineers decide, the existing MEP will be demolished completely or bits and pieces demolished.

I would like to ask you, my readers, who may be experienced with Revit MEP and renovations/additions... Do you model the existing MEP components?  Or maybe just the HVAC portion?

Any and all feedback is welcome... I think this will help my readers as much as it will help me.

Revit 2012 - New Architecture Features!

Revit Architecture 2012 is just around th corner and there are two notable features (that I am the most excited about).  Of course, there are more and I will be filling you all in soon...

• Parts
  Being able to break a wall apart by components and push, pull, and manipulate many system elements is a huge enhancement in my opinion.  For me, a student and intern architect, I am excited to use this for stunning and "WOW" factor visualizations...
  
  More to come..
   
• Visualization Enhancements
  Again, the enhanced visualization you will find in Revit 2012 is going to make Revit presentations look incredible.
  - Ambient Allocation in ALL VIEW TYPES!
  - Semi-Transparent Elements
  - Enhanced edges.
  - Shadows in "Consistent Colors" style.
  - Ability to Create your own templates for visual styles.

Those two features alone make it worth it for me...

Of course, I do not have to go through all the details because there are plenty of blog posts about it already out there.  I actually watched the invite only Blogger webcast in the back of class... shhhhhh... Don't tell my teacher. So I couldn't get any great screen shots...

Head over to David Light's blog for the best post on Revit 2012 so far....

And boy is it a great post.  David, I am sure all the bloggers thank you for the post...