Inside the System

Thermodynamic Fun With Math

This Revit MEP wiki-help article digs into computing water flow requirements based on air flow and design assumptions.  It gets into interesting topics such as 'cancelling units', and adding and subtracting temperatures.  I'm sure this is just what you were pondering this Friday AM.

Have a good weekend!

Multiple Circuit Device in AutoCAD MEP

In the Discussion Forums, a user inquired about how to tag both circuits on a multi-circuit device, such as a quad receptacle with two connectors, with a tag like P1-1,3.

The Device's automatic circuit property only reports the information about the first connectors.

The trick to annotating such a device is to use an 'invisible' wire, wire the two connectors together, then tag the homerun.  See this brief video. 

For some reason, when the second connector is added, the original device instance doesn't seem to 'read' the second connector into the wire... however, new instances of the Device work as expected.  This issue has been logged with the development team.

TIP: Creating Pipe/Duct Fittings in Revit MEP

One frequently overlooked requirement when creating fitting families (specifically elbows) in Revit MEP is that the vectors from the connectors, if extended back into the family, must intersect at the intersection of the Left/Right and Front/Back reference planes.  Otherwise, strange behavior will be observed when routing elbows with the pipe or duct tools.

 

There is a comprehensive tutorial for building a pipe fitting from scratch available here: http://usa.autodesk.com/adsk/servlet/item?siteID=123112&id=13376617  The documents available at this link are the Revit MEP 2010 Families Guide.  The UI may be slightly different in current releases, but all the same concepts apply.

New Duct User Interface in AutoCAD MEP 2012

As you may have found by now, AutoCAD MEP 2012 introduced a new user interface for ducts.  The goal of this was to move the interaction to the Properties Palette for adding and editing duct, similar to the changes made to pipe and conduit in prior releases.

For the most part, you will find that the settings in DuctPreferences have been moved onto the Properties Palette, making most configuration settings available everytime you add a duct, instead of having to dig into a separate set of windows. 

The following series of images shows where the DuctPreferences settings in 2011 (image on left) correspond to the settings on the Properties Palette in 2012 (on the right).  In a couple of cases, settings are still found in the DuctPreferences window, and some settings are now found in StyleManager.

Click on an image to enlarge.

Routing

 
 
Ducts

 

Vanes and Flanges

 

Flex Ducts

 

Parts

 

Connections

 

Adding Duct