Wednesday, April 23, 2008

Revit Architecture 2009 to gbXML – Problematic Structure

Last week, one of the students in my course on BIM tools for sustainable design created a model that had an excess of shading surfaces and as such was rejected by Green Building Studio as invalid geometry. In order to remedy that I suggested that the same model could be processed within Revit Architecture 2009 since, as I have mentioned before, it has the ability to strip the model of excess shading surfaces. At that point this seemed like a good idea, right? Wrong. The model, which had been 4 MB in size, grew to be 48 MB in size and needless to say it was not applicable for simulation. We submitted the XML file to GBS for their analysis, and this is what they found:

RAC 2008RAC 2009
raised floor183650

This morning I decided to put a simple model created in RAC 2008 to the test and, since I suspected that having the structural elements might have something to do with XML output, I placed a simple round (pay attention to the word “round”) concrete column in the center of this test structure. Analysis of the 2008 XML file did not show anything unusual, so I proceeded and opened the same file in RAC 2009. Not to my surprise the newly generated 2009 file quadrupled in size and these are the findings:
RAC 2008RAC 2009
The round column is being defined with 32 segments, and just for the future reference when modeling curvilinear geometry think of the polygon count, as even in these BIM days it still matters.
The conclusion is that the structural element is subtracted from theroom volume, the void is therefore tessellated, and surface type enumerators are assigned to the newly generated surfaces. Interestingly the enumerator for the vertical faces is the exterior wall, and this poses an alternate problem related to the overall calculated mass of the analytical model. Now, although in both versions of RAC the structural element is designated as Room Bounding, somehow RAC 2008 was semi-smart about it and it was ignoring them, where RAC 2009, possibly due to the enhancements with the room object, is quite happy in exporting those structure bound faces as well as exponentially increasing the size of the gbXML file.
In order to make previously created RAC models applicable, one should declare all of the structural elements as non Room Bounding and by simply doing this the gbXML output from RAC 2009 will be almost identical to the one from RAC 2008. This will increase the usable room area within the project, but we can all agree that this is the small price to pay for being green, or maybe not?
The only slight difference in the file size will be caused by the changed nomenclature within the 2009 generated XML file that is used for more eloquent description of exported surfaces.You can download both the 2008 and 2009 samples and their corresponding XML files by following this link.

Tuesday, April 22, 2008

Green Building Studio - Ingenuity Point Winner

Green Building Studio helps designers, architects and contractors build energy-efficient structures with as small a carbon footprint as possible. Its web-based analysis services gives architects and other building industry professionals an intuitive way to take a building design from carbon-positive to carbon-neutral in a matter of minutes versus weeks.
(Read more)

DOE - Launches Website with Energy Saving Tips

The U.S. Department of Energy (DOE) today launched a new internet feature which provides tips to consumers on how to make everyday Earth Day by making smart energy choices to save money while protecting the environment. The interactive web page shows consumers steps to use less energy with household electronics, lighting, and appliances to save on monthly bills and how to avoid wasting energy by improving the energy efficiency of their homes and cars.

Wednesday, April 16, 2008

ecoDriver - reducing your CO2 footprint

ecoDriver suite of products have been specifically developed for companies and institutions who are keen to reduce their utility costs but who are primarily concerned with improving their organisation’s sustainability.

  • Monitor energy & water usage, business travel, etc
  • Alert consumers when consumption exceeds targets
  • Prompt action to reduce consumption
  • Provide feedback on success of action taken
  • Engage employees in sustainability endeavours

Tuesday, April 08, 2008

Energy Design Plugin for Google SketchUp

The Energy Design Plugin is a free plugin for the Google SketchUp 3D drawing program. The plugin makes it easy to create and edit the building geometry in your EnergyPlus input files. The plugin also allows you to launch EnergyPlus simulations and view the results without leaving SketchUp.

Monday, April 07, 2008

Review of the development and implementation of IFC compatible BIM

One of the most comprehensive, and the least "cool aid drinking", reviews on implementation and interoperability of BIM complaint platforms in European AEC industry.

Sunday, April 06, 2008

Are Highly Efficient Buildings Sustainable?

An intriguing article by Dr. Marsh (Ecotect) in which he juxtaposes the benefits of design versus operational efficiency.
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Friday, April 04, 2008

Big Green for Deep Blue

IBM Builds Green Data Center for GIB-Services; Innovative Technology to Heat Local Public Swimming Pool....
(Read more)

Tuesday, April 01, 2008

Green Buildings in Google Earth

"What are "green buildings"? This KML showcases buildings across the United States that are included in the Department of Energy's High Performance Buildings Database, which features buildings that meet certain energy and environmental performance guidelines. Be sure to click the "View 3D model in Google Earth" link to see a 3D virtual representation of the building."