Tuesday, April 01, 2008

Tale of a Round Trip - Revit MEP Family and RAC

Attended a local user group recently and an attendee asked if it was possible, and/or useful, to use a Revit MEP (RME) family in a Revit Architecture (RAC) model, for example a toilet. The answer given was yes, but we would lose plumbing engineering functionality of the toilet while working with it in RAC.

First the greatest advantage to using a RME toilet in a RAC project is if the RME team is going to actually work on the same project file. While this is certainly possible it might not be very likely for at least two reasons, separate firms doing the work and model/Revit performance (based on project size).

A second possible advantage is that RME users can Copy/Paste elements in a linked RAC file into their project. If it is already a RME toilet, using the same example, then it is now ready for pipe. The RAC user can decide if they want to keep their toilet or let the RME version stand in now, much like Revit Structure (RST) columns ultimately replace the ones the RAC user placed originally.

It was suggested that Revit might change the family if it was used in RAC and then returned to RME. I didn't think that would be the case so tonight, just for grins, I did two different tests:

1 - RME Toilet round trip between RME and RAC in the project environment to see if Revit did anything unkind to the family. Answer - no!

2 - RME Toilet round trip between RME and RAC in the family editor environment to see if Revit did anything unkind to the family. Answer - no!

The primary difference in both cases was that most of the RME specific features were visible but inaccessible to the RAC user. Here's the dialog box captures for each sequence, starting with the project environment.

RAC Project - Properties

RME Project - Properties

RAC Family Editor - Connector Properties

RAC Family Editor - Family Types

RME Family Editor - Connector Properties

RME Family Editor - Family Types

You can see that the family survived being opened and saved in both RAC and RME without harming the usability of the family in either version. In fact in RAC a few of the parameters, like Flow Pressure is still editable, while other engineering criteria are simply inaccessible.

So the question remains, what benefit is there to use RME families in RAC if you are not working within the same project file? Well apart from the Copy/Paste tool letting your RME consultant use your fixtures, I suppose not much!

Well that was fun!


Dave Baldacchino said...

Thanks for testing this in detail. As you pointed out, there's not much benefit to re-creating families in RMEP just because of connectors. RMEP users can still copy toilets into their project from the RAC link and quickly substitute them with their own families. This means that the two disciplines need to coordinate their content so it can be exchanged easily without unnecessary shifting (common origins), which might be easy in-house or if you use the same consultant over an over, but be quite challenging otherwise. On the other hand, I really do like the idea of a "liason" between the RAC families and the RMEP ones (rough-in connectors). That makes the blurry line that defines who-does-what blend in quite nicely.

Paul Jordan said...

Why not just use all the Revit MEP families in Revit Arch.. Why is there a difference in the two?? If the Archie wants to put toilets in, let him, then when you take it to Revit MEP, they're already there, all you have to do is plumb them. Sounds simple to me.

Steve said...

I guess my post didn't explain it clearly enough then...

If the architect puts RMEP fixtures in their model the engineer cannot connect to them if using a linked file strategy. The connects are "out of reach" in the link.