Graphics Programs Reference
In-Depth Information
Now you have complete model information set up to be read by a simulation
program without issue and without any further manipulation, right?
Unfortunately, that is not the case.
A major issue with the exported data deals with the building construction.
Revitbreakslargerelements,suchasafloorslabinlargeorcomplex-shaped
spaces, into smaller polygonal elements for computation. This means that a
single floor element is broken into several individually tagged and defined
floor elements in the same space. Revit MEP also has a tendency, depending
on how the architectural link is modeled, to assign exterior wall values to
interior walls that bound a space, or roof values to ceilings that bound a
space.
If your design space has an unusual or atypical geometry, such as a curved
wall, the number of individual elements within a single type can grow to the
hundreds. This is a prevalent issue when trying to import your gbXML file
into an outside simulation program. There simply is not enough capacity
in the third-party programs to handle large numbers of building
surfaces—sometimesstoppingatthefirsteightsurfacesandcausingyou,the
designer, to have to examine each space individually to delete and remodel
any surfaces in error.
Also, importing errors may occur when parameters such as the construction
data U-values fall outside a common range predefined by your simulation
software. Often it will prompt a warning message, but at other times the
gbXML data will fail to import completely. Most of the time, the remedy,
again, istocheck each individual building element construction orassembly
to make sure that the appropriate U-values are modeled. Otherwise, you
are forced to create the assemblies manually from scratch. In addition to
checking the construction, make sure your simulation program has properly
read the internal load data—manually adjust or enter the data as required.
Do not be discouraged. Yes, you may experience some drawbacks when
exporting and importing gbXML data from Revit. As a designer, any effort
you make to reduce the time-consuming process of modeling each space of
the building in your simulation program will be worth the effort. Although
there are some shortcomings, with Revit MEP 2015 you have the ability to
examine the model geometry and data within the space prior to analysis,
which can save time on your projects and improve coordination.
