Friday, December 21, 2007

DWF - Design Options with Design Review

Thanks to RobiNZ and his blog post this great tip did not go unnoticed. For quite some time I have advocated and used DWF - Design Review as a communication and design tool, but not knowing the fact that rearranged objects can be captured in their location via user defined views, made me rely on creation a snap shoot sequence.
This technique described in Beyond the Paper blog is the right way to do it...

Thursday, December 13, 2007

IES Revit Architecture 'Plug in' Now Available

IES is pleased to announce it has developed a free plug-in to Autodesks Revit Architecture which provides a direct link to its software and to the companys new architect-orientated Toolkits.
(Read more...)

Download the plug-in....

Wednesday, December 12, 2007

Transstudio and Transmaterials

Great resource for everyone that is trying to operate within the evermore demanding field of performance based design.
Watch the video, and subscribe to the free material newsletter...

Wednesday, December 05, 2007

EnergyPlus for Google's SketchUp

DOE plans to release an EnergyPlus plug-in for Google's SketchUp at the end of 2007. This free EnergyPlus plug-in will integrate building simulation functionality into the SketchUp drawing environment. The plug-in stores EnergyPlus input data on SketchUp surfaces as they are drawn by the user. An EnergyPlus toolbar provides a way to create zones and surfaces with only a few mouse clicks. Construction assignments are 'painted' onto surfaces using a palette of EnergyPlus wall, roof, and window constructions. Users will be able to execute an annual simulation from within SketchUp. Watch the EnergyPlus web site and email for more information.

(Read more in the latest edition of Building Energy Simulation newsletter...)

Friday, November 30, 2007

Autocad Architecture LEED EQ 8.1 update

After some positive feedback and a few constructive suggestion here is the updated LEED EQ 8.1 Daylight Factor interactive schedule that takes into account Net Area and Door/Window Assembly objects.

Thursday, November 29, 2007

Revit to gbXML - What does the window want to be?

As I was finishing my tutorial on manually placing shade devices as part of Revit's model envelope, I stumbled across this rather interesting "feature" that was exhibited while translating geometry into the gbXML file format. But before I continue to describe that particular Revit to gbXML behavior I need to make a correction to a statement in my previous article where I was testing Revit's ability to model shading devices by using In-Place families.

"Shading devices, constructed or planted, exterior or interior, can be approximated in Revit's BIM model via the persnickety use of a variety of modeling objects, but within Revit Architecture there is no identifier that designates any such improvisation as a valid gbXML compliant Shade surface. Someone might ask, but what about using a roof or a slab family to create exterior shading devices? Sounds like a good idea, but unfortunately to export such an element, the same one should be a part of a room bounding enclosure."

I need to praise Kyle Bernhardt for pointing out that this statement needs to be revised as follows: In Revit Architecture one can use Floors or Walls (stick with generic) to represent the shading surfaces. The Walls and Floors that are of the System Family type will get exported, but if you attempt to model them as In-Place families they will be ignored.
This means that any articulated solid extrusion made as an In-Place Wall or Floor will not be exported to the gbXML file.
Nevertheless in order to successfully export the objects mimicking Shading surfaces into the gbXML file, the warning message stating that a particular Room Bounding element is ignored should be disregarded and one can proceed with saving a new gbXML file.
Now back to glazing.
In order to test the available Window families and their corresponding operational (descriptive) parameter within the Revit Building Model, place an array of different window families along one wall in a sample model in order to see if the translated output will properly identify these windows according to the Window Type identifiers that are outlined within gbXML schema version 0.34.
Those Window type identifiers are as follows:

  • FixedWindow
  • OperableWindow
  • FixedSkylight
  • OperableSkylight
  • SlidingDoor
  • NonSlidingDoor
  • Air

When building a model, if you resort only to Window families for facade apertures it really does not make any difference what type (Casement, Fixed, Awning, Glider etc.,) is used, as all of those will be translated with the "OperableWindow" gbXML type identifier.
The opposite in this glazing interpretation is that all of the Wall Family based glazing (Curtain Walls, Storefronts) is always translated with the "FixedWindow" gbXML type identifier.

The ability to eloquently articulate glazing performance in any building submitted via gbXML for analysis can not be regarded as accurate if the designer does not have the utmost control over the ventilation character of glazed surfaces. Unfortunately, within Revit Architecture we do not have the capability to designate windows operational descriptor, which means that the Curtain Wall family based glazing will always be simulated as non operable, whilst the Window family based glazing will always be characterized as operable type glazing.

One quick way to remedy this is to identify an element's ID and use it's value to parse and edit the gbXML file before is submitted to Green Building Studio for further analysis.

To mimic the sentiment of people that are trying to use Revit Architecture for Building Performance Analysis, it is quintessential to make some functionality changes to Revit's Room Object and make it behave more like the eSpace objects in Autocad Architecture where all of the relevant gbXML type identifiers can be directly assigned to the analytical space and its bounding elements such are walls and openings.

Google’s greenbacks power green RD

This week, Google announced it expects to invest hundreds of millions of dollars in renewable energy over the next few years, and that it's setting up a research and development initiative called Renewable Energy Cheaper Than Coal...
(Read the entire article...)

Tuesday, November 27, 2007

Digital Pen for Autodesk BIM platforms

Adapx (, the company that is changing the economics of field data management, today announced that the first public demonstration of Capturx for Autodesk(R) products will be held at the Autodesk University Conference in Las Vegas, November 27-29. Attendees can get a sneak preview of the Capturx enterprise-ready digital pen ...
(Read the entire article on marketwire)

Thursday, November 22, 2007

LEED EQ 8.1 Credit (Daylight and Views) for ACA 2008

(Real time daylight design tool for AutoCAD Architecture 2008)

In 2005 when my article on BIM and knowledge management was published, I indicated the opportunity within BIM as a methodology that has the potential to capture cumulative knowledge that aggregates within a firm and to implement the same within any BIM compliant platform.As we all understand the need to evaluate the performance of our buildings, the need for this knowledge integration is even more evident, and one avenue via which we can explore this methodology is in the integration of LEED credits compliance within the BIM model.
The Importance of LEED certification and its necessity for the creation of a sustainable built environment can be debated from several perspectives but considering the integration of real time evaluation tools should be a prerequisite for the creation of any expert system that will be used for instantaneous knowledge (code / rule) feedback.

I have to admit that, besides a few scheduling screen shots in Revit Architecture and some in articles that were relevant to AutoCAD architecture, I have not seen any serious attempt to tie in more closely any application with the concept of LEED credits take-offs or any LEED scheduling framework provided by the software manufacturers.

Now some of you could ask the question why this example is not available in Revit Architecture, and the answer to this is quite simple. I do not know how to make it work, and in this instance I will blame this on my own ignorance unless some one out there can actually explain to me why one has to calculate the area property of an room object as a result of volume by unbound height division as this, in spaces that have a sloped ceiling, will produce an unacceptable inconsistency.

So in order to have an interactive real time daylight factor analysis tool one should work with these ingredients:

Window use classification
Window style
Property Set Definition
Space style Property Set Definition
Display Theme for DF (Daylight Factor)
One not particularly customized schedule
And a few lines of VBS code slowly brewing in the background.

First we start by defining a window object classification category that defines any instance of a style as either an EXTERIOR or INTERIOR window, where only those that the user marks as EXTERIOR will contribute to the EQ8.1 calculation.

The second step is to define three different List Property Definitions whose values represent different window factors that are required for DF calculation. Those factors are:
GF – geometry factor
HF – height factor
TVmin – minimum visibility factor
TV – visibility factor

which are all dependent on window type, location and current glazing visibility as presented in this table.This method assumes that values are associated with a particular window style and in order to vary them from instance to instance one should copy and assign style in place and change the style based property definitions in order to accommodate for these variations.

On the other hand the Space Objects Property Set Definition has been modified in order to perform a required DF analysis by querying the current file for all of the windows that have matching location ID with the space objects for which the calculation is executed. The matching ID within every window object is placed within the Window Styles Property Set Definition via Location Property Definition and thereby the logical spatial link between two objects is established.

For the sake of differentiating from the OOTB Property Set Definition I decided to create two new PSD one for Window Styles and the other one for Window Objects.The object based one is labeled as 01_LEEDWindowObject and this is the one where the link to the Space Object is documented through the “WindowSpaceID” property definition while its relevance for DF calculation is established by the “001WinLocation” classification based property definition. The space based PSD is labeled as 01_LEEDWindowStyles and this is where the previously described window variables are hosted.

LEED_GF”, “LEED_HF”, “LEED_TV” and “LEED_TVmin” are all style bound and this is where the associated space object reads the relevant values for its daylight formula.To visualize DF in real time I have included a basic Display Theme that is providing for a graphical feedback based on the calculated DF.
Tying all this together was executed within Space Objects PSD and in particular within the formula property definition that taps into two ADT libraries in order to make this work.

Set acadApp = GetObject(,"AutoCAD.Application.17.1")

Set AecBaseApplication = acadApp.GetInterfaceObject("AecX.AecArchBaseApplication.5.5")
Set SchBaseApplication = acadApp.GetInterfaceObject("AecX.AecScheduleApplication.5.5")
Set ActiveDoc = AecBaseApplication.ActiveDocument
DF_win = 0
DF = 0
PropValue_GF = 0
PropValue_HF = 0
PropValue_TV = 0
PropValue_TVmin = 0
WinArea = 0
For Each obj In ActiveDoc.ModelSpace
objName = TypeName(obj)
If objName = "IAecWindow" Then
Set objPropSets = SchBaseApplication.PropertySets(obj)
Set objPropSet = objPropSets.Item("01_LEEDWindowObjects")
objWinLocation = objPropSet.Properties.Item("_WindowLocation").value
objWinSpaceID = objPropSet.Properties.Item("_WindowSpaceID").value
If objWinLocation = "EXTERIOR" and objWinSpaceID = "[ObjectID]" Then
Set PropSets = SchBaseApplication.PropertySets(obj.Style)
Set PropSet = PropSets.Item("01_LEEDWindowStyles")
PropValue_H = objPropSet.Properties.Item("Height").value
PropValue_W = objPropSet.Properties.Item("Width").value
WinArea = (PropValue_H * PropValue_W) / 144
PropValue_TV = PropSet.Properties.Item("LEED_TV").value
PropValue_TVmin = PropSet.Properties.Item("LEED_TVmin").value
PropValue_GF = PropSet.Properties.Item("LEED_GF").value
PropValue_HF = PropSet.Properties.Item("LEED_HF").value
DF_win=(WinArea/[BaseArea])*PropValue_GF*(PropValue_TV/PropValue_TVmin )*PropValue_HF
DF = DF + DF_win
End If
End If

RESULT = DF * 100

Without going into a lengthy discussion about what this VBS is doing, I just want to point out that the main loop is using SchBaseApplication object to access the property set of each window instance in ModelSpace object and compare its “_WindowSpaceID” property to the [ObjectID] property of the current Space Object.If the match has been confirmed within the first If statement of the outer For Each – Next loop and the examined ModelSpace object is indeed of IAecWindow type, then the second If statement is comparing “_WindowLocation” and “_WindowSpaceID” properties.
When both of these requirements are met than the set of relevant variables is accessed via SchBaseApplication object and are being channeled to DF_win formula that is being compounded within the primary loop to create the final DF value for this given Space Object.

In order to evaluate the final daylight value for a floor plan I have created a schedule that does it, but similar compounding and property extraction code could have been used to calculate the final result within a Space Object.

The prerequisites for this DF real time calculation method are the following:
ACA 2008 or ADT 2007 due to their capabilities to apply classifications to an AEC object and their use of List definitions.
This code can be retrofitted to operate within ADT 2006 and 2005 in a slightly less sophisticated way.
The code within a Space Object can not query window objects within a x-ref file and therefore both the envelope and spaces have to be part of a same construct, or a plain independent file. It is worth mentioning that the code within these customized SpaceObjects is taking a toll on ACA’s performance, but as I have tested it on a 60000 SF project with the acceptable performance the entire process can be even more streamlined during the initial design by having a zonal approach to DF evaluation.

After downloading this sample file the user should try to rescale the windows associated with their spaces and observe the change in color as the DF for this space crosses the threshold of 2%. It is worth noting that in order to create a window with the different performance values the existing style should be copied into a new style and those values should be adjusted within this new style based Property Definitions.

For any of you that have ever driven a certain French car, and you know the connotation, and especially those that were made between 1955 and 1979 by a company which I will not name but whose creation was closely connected with the architecture of Le Corbusier, you will understand my enthusiasm with this, not officially BIM like, Swiss army knife application that is still quite a useful BIM tool if you know which buttons to push. Thanks to the inspiring work of several people, like David Koch, Jimmy Bergmark, Jay Moore, Robin Capper and few others that are not yet ready to give up on the potential of embedded code within BIM compliant objects, this application proves that a good amount of intelligence can be placed behind a comprehensive BIM model.
For myself, I can not but wonder if ADSK is really listening, as I am quite sure that a few skilled programmers, and ADSK has enough of those, can crank out this code in a matter of minutes and have it become an integral part of the AutoCAD Architecture. The bigger picture is that ADSK should at least make an honest attempt to add the tools so needed in this “non BIM” application so that we can really take the full advantage of the outdated “object” technology.

This file includes all of the above described elements and I am encouraging you to test it on your own LEED projects. Being aware that there is a ton of room for improvement to this proposed code as well as that this can be far more efficient code if executed via VBA or VB, I am looking forward to get some constructive feedback.

Wednesday, November 21, 2007

Green Building Studio - Support Pages

For all of you using Green Building Studio's web service, a new resource describing the knows issues is available at this location.

Wednesday, November 14, 2007

Solar Heat Gain control in Revit's gbXML model

As some of us have ventured down the road of Building Performance Analysis (BPA) it is to clients' benefit that we fully understand that the path between BIM compliant, or want to be a compliant model and the simulation model doesn't have to be a black box. Thanks to the visionary (read common sense) approach in interpreting virtual building objects and to the creation of a standard language of building, one can regard gbXML format as the first line of defense against inaccurate modeling or translation results.

When exporting a model into an ASCII compliant XML file or examining the same model via its VRML incarnation, one can quickly validate the integrity of the model translation, or manually modify the same file with a very basic text or XML editor. This to a certain extent can compensate for the current software shortcomings or one's unwillingness to purchase another $5K software package.

Let us see what the average user can do to enhance the quality of the preliminary model interpretation, and what are the basic elements of the gbXML file that we as architects should understand in order to approach schematic design modeling with realistic expectations. To do this, knowledge of BIM compliant model structure is the key component, and reflecting on how this model is put together will yield to greater appreciation for the simplicity of its analytical counterpart. The BIM model as such, appropriately so, is distilled down to its basic analytical geometry by treating each major construction component as a 2 dimensional surface (plane) with its associated information, and this associated information is what really distinguishes the building's components in their analytical environment.

The purpose of this geometrical interpretation is the functional and data rich translation of the somewhat superfluous BIM supporting platform geometry, and to emphasize the irony of information modeling, only the spatial components and functional labels of BIM model objects are conveyed to the simulation software. So instead of true information modeling that incorporates usable physical and temporal data ,the grunt work is done after the model is submitted and from that perspective that famous "Information - Cost" BIM diagram becomes somewhat questionable.

Once we establish this common understanding of BIM's model capacity we should find a way to manipulate the purpose built model and its information after it is being exported to gbXML.
Now let's get to the very basics and learn what are the "building blocks" of a gbXML file. Not to be surprised, but the basic Euclidean surfaces are what defines the space and consecutively the building within the analytical model, and those surfaces are defined as follows within the gbXML schema;

  • InteriorWall
  • ExteriorWall
  • Roof
  • InteriorFloor
  • Shade
  • UndergroundWall
  • UndergroundSlab
  • Ceiling
  • Air
  • UndergroundCeiling
  • RaisedFloor
  • SlabOnGrade
One could ask why even mention these surface types as your BIM application can easily translate any model into a comparable gbXML file that can be sent for analysis. Therefore through a simple iterative process, the architect/designer should be able to optimize a design toward finding the most viable sustainable solution. Or is it so?

The short answer is not at all. Yes, indeed the basic building geometry focusing on slabs, roofs and walls will be generated as it defines the spatial boundary conditions, but several of the quintessential passive sustainable strategy elements get entirely neglected.

Shading devices, constructed or planted, exterior or interior, can be approximated in Revit's BIM model via the persnickety use of a variety of modeling objects, but within Revit Architecture there is no identifier that designates any such improvisation as a valid gbXML compliant Shade surface. Someone might ask, but what about using a roof or a slab family to create exterior shading devices? Sounds like a good idea, but unfortunately to export such an element, the same one should be a part of a room bounding enclosure, and besides extending slabs beyond the buildings envelope, the aperture shading definition does not comply with Revit Architecture's capacity for model translation to gbXML.

Following is the technique I use to circumvent the above described deficiency and append my own shading surfaces to the analytical model, and for its implementation a good XML editor and any VRML browser are must have tools. The editor I prefer (read free) is XML
Marker , and the VRML browser I prefer is Cortona by Parallel Graphics.

As indicated in the previous article that was dealing with the ambiguous interpretation of different glazed opening types, in this one we will also rely on the gbXML surface type and its child object opening.
In order to manually indicate the location of a shading device, it is important to locate the surface which is hosting an opening, bringing us to an interesting modeling concept in which we assume that main building elevations are perpendicular to coordinate axis substituting for sides of the world and where by the convention we assume that North is in the positive Y direction. We can certainly model any structure to reflect its true site orientation and this would not pose a particular problem, but explicitly specifying building's orientation angle is something I like to avoid at this point, especially when considering the fact that GBS can rotate the world around any structure.
So go ahead and export your Revit Architecture model and make sure that all openings are properly translated by verifying their location within the VRML file. If you adapt the translated VRML file so that it can be used within the VRML client as shown in this example, it is quite easy to identify which opening's location will be used to manually place the new shading devices.

To find the appropriate surface and the associated opening one should parse the gbXML file and look for the Surface-Opening Parent-Child pair. To verify its association with the original Revit's entity one should always compare CADObjectID value of the surface with the entity ID value in the model. Once you find this, look for the Cartesian point that determines the location of the child object in relationship to its parent.

As indicated in this code example

This same point will be used to intentionally place the shade surface in relationship to the opening object. As we are examining the opening object ,it is worth taking a second look at Revit Architecture's translation of its window families into the gbXML file as some inconsistencies will become apparent. It is always up to the user to double check the interpreted definitions and manually modify the gbXML file in order to assure for the correct window operational type translation. One major improvement to Revit's gbXML output would be the ability to to pick the appropriate gbXML type definition and have it as a parameter within the relevant family, but circumventing this problem is a topic for the next post.
Confirm the type and the location of an opening with its vertices and its parent exterior wall surface. When this is done, adding a shade object is a relatively straightforward exercise, which consists of appending desired number of shading surfaces at the end of the gbXML file and naming them incrementally as shown in the example below.
While parsing the gbXML you will notice several definitions within the surface element such are "RectangularGeometry", "PlanarGeometry", "Azimuth", "CartesianPoint", and "Tilt" where the explanations for all of them are given within the
gbXML schema, and the accompanying documentation.
So whether a shade device is aligned with an opening or located relatively to an exterior wall surface, all you have to do is to identify the opening vertices within a surface or the vertices of the surface itself, and use those to locate, orient and size the corresponding shade surface.

Save your gbXML file and submit it to the GBS web site under the same project name as the original file and compare the results. You will notice that specifying windows' operability value, as well as introducing the correctly placed shading device will make a difference in the total energy picture of your project.
As I mentioned in my previous article, it might be prudent to eliminate all of the unwanted shading surfaces that are artifacts of Revit's model to gbXML translation, and then introduce a new set of deliberately placed Shading Surfaces / Devices whose syntax is described below. Make sure that you assign an unique Surface ID and associated surfaceType as "Shade".

As indicated in this code example

Unfortunately the lack of an existing native gbXML editor makes this process labor intensive but the insight into the future performance of a new design, in my opinion, makes this entire exercise quite valuable.

Monday, November 12, 2007

BLAST FROM THE PAST - (----- Architecture 1962-72)

How much are you willing to pay for forty five (45) year old technology?
Well, to see what parametric modeling looked like in 1962, and what is still to be desired after all these years, everyone that is mildly interested in BIM and BIM compliant applications should watch this video.

Saturday, November 10, 2007

SketchUp goes Green

Greenspace research has just release a new beta version of Demeter plug-in that expands the benefits of using Google SketchUp for preliminary design process. This plug-in provides the ability to perform the early energy design analysis within minutes, as well as the ability to import and export the gbXML files.
Some of the features are:

  • Properties assignable to surfaces
  • Enclosed space identification
  • Boundary surfaces assignment
  • Contiguity checking
  • Integration with USA and UK version of Green Building Studio (This is BIG!!!)
  • Import and export of gbXML files
  • Direct export of SketchUp model for the Whole Building Energy analysis

The only question that remains to be answered in whether we are witnessing the rise of low cost BIM application and how effective is this more than welcome integration with Building Performance Analysis software.

Thursday, November 08, 2007

Green Building Studio 3.0 - Released

The Green Building Studio has recently announced the release of GBS Version 3.0. This new version is designed for architects to use on all their design schemes on each project to ensure every building they are designing is carbon neutral ready. Exciting new features include:

  • Carbon Neutral Building Check – Automatically estimates the feasibility for each building to achieve carbon neutral status using local grid emission data. US EPA ENERGY STAR Score – Computing each building's US EPA ENERGY STAR score or Architecture 2030's targets.
  • Water Use Analysis - Estimates the water needs, savings associated with efficiency measures, rain capture potential, and LEED credits for the building.
  • Daylighting with Energy Savings – Automatically determines LEED Daylight Credit and room by room glaze factor analysis.
  • Natural Ventilation Potential – Automatically determines if the building location and loads are well suited for naturally ventilating the building.
  • Local Weather Data – Providing access to over 50,000 weather locations, ensuring the design team uses local hourly weather data within 9 miles (14km) of your building rather than selecting from the typical 230 airport locations.
  • Onsite Renewable Energy – Automatically analyze every exterior surface to determine all the best performing photovoltaic surfaces. Discover annual energy generated for your building from a wind turbine.
  • Corporate Accounts – Providing firm-wide management of users, building designs, building templates, and review of corporate wide CO2 emission, energy and water use analyses. Leverage key staff on every project no matter which office they are in.
  • Passes Industry Standards – ANSI/ASHRAE Standard 140-2004, Qualified Software for Energy Policy Act of 2005, & Microsoft Platform Test for Hosted Solutions (Platform test was conducted independently by VeriTest).

See the video, which demonstrates how to design a building to be carbon neutral in five minutes using GBS Version 3.0!

Wednesday, November 07, 2007

Smart Sustainable - Environment Driven Geometry

Intelligent skin, adaptive structures, mathematical and mechanical interpretations of nature generated forms, and much more in the work of HOBERMAN TRANSFORMABLE DESIGN studio... (link)

Smart Geometry 2008 Conference

The SmartGeometry Conference features a day long agenda focused on advanced computational and parametric design.
Hear from industry leaders as they discuss the issues of design, technology, and methodology through their presentations. Parametric design tools and consequential manufacturing technology are allowing new forms of architectural and structural expression which are changing radically the world of the built environment....(link)

Monday, November 05, 2007

Visualizing Thermal Transfer Data in AutoCAD Architecture

This example focuses on a presentation technique that architects could use to clearly communicate their decision in the choice of building envelope composition. The wall object in AutoCAD Architecture (formerly ADT) can convey a vast amount of information, both automatically generated and user added, but in respect to physical properties and the way those can be visualized does not provide for any analytical depiction. Yes, we can add an array of information to individual wall layers, and if we get really adventurous we can use ACA's powerful and mature API to access those wall sub components and through material definitions assign values like thermal conductivity and embedded carbon footprint, but this would be a topic for a different post.

Click to see DWF model

What I tried to accomplish here is to visualize the thermal transfer data within this particular wall/window detail with a help of a really amazing free analytical tool the Steady State Heat Transfer, Therm 5.2. To achieve this I have modeled a fairly accurate window sill condition in AutoCAD Architecture, by using custom end caps and strategically placed Mass Element objects.

After cutting the section through this assembly and detailing it by using the Detail Component Manager , this drawing was exported to a DXF file for the purpose of bringing it in as the background into THERM 5.2. In this application, that is available from
LBNL, the appropriate materials and boundary conditions were, so to speak, "painted" over the imported CAD underlay. This means that for every polygon that represents a different material in section we have to assign the appropriate material definition, and for those polygons / materials that are exposed either to the exterior or to the interior we need to assign the set of boundary conditions. In order to do the meaningful approximation, adiabatic boundary conditions are assigned where the top and bottom section cuts occur.

It is worth mentioning that even though THERM 5.2 comes with an extensive material library, you will still have to do your due diligence in order to define some of the missing construction materials, if approximation is not an option.

The pseudo IC thermal images can be exported into an image editor of your choice and applied as the bitmap within a ACAD/ACA material that will be mapped onto a Region object generated from 2D section object. After a few tweaks in respect to mapping of the newly created material thermal image is assigned as the diffuse map and its inverted B&W image as the opacity map. Enabled live section of this model has been exported as the DWF file for an easy share with anyone that is interested in the thermal performance of a building's envelope on any given project.

In this example even though the analytical data does not reside within BIM compliant model, we can use the very same model as a link to the external data and more effectively communicate or justify the design intent.

Friday, October 26, 2007


In these days of BIM this often overlooked, but still very relevant, organization is an excellent source of a vast theoretical knowledge on the implementation of digital technology in architecture. It is definitely worth joining, even in the case that you only want to get their annual conference proceedings. If you really want to know where BIM is coming from, ACADIA is the place to start.

Monday, October 15, 2007

Clerestory - or not so clear....

It is undisputable that glazing is a crucial element of a building's envelope and from that perspective the kind of glazing that is implemented on a project can greatly contribute (or not so) to the overall thermal and day lighting characteristics of a building.So what do we have to do within Revit in order to be able to depict the most accurate aperture configuration of one’s preliminary design? First we need to take a look at the way Revit is interpreting objects like Windows, Store Fronts and Curtain walls when embedded within a wall opening and exported to a gbXML file. When you start modeling in Revit, do yourself an enormous favor and forget about anything else bur Generic Family types, and for all the practical purposes stick with generic walls, slabs, roofs, windows and doors, as none of their construction characteristics are conveyed to GBS via gbXML. One of the undocumented idiosyncrasies of Revit’s interpretation of openings is that any glazed component of a buildings skin is being exported to gbXML as an OPENING of a “FixedWindow” type, and nothing would be wrong with that at the schematic design analysis if that interpretation was modeling style (family) independent. Well it is not.While modeling a series of case studies for future training material based on several past projects, the quintessential architectural element the clerestory window became a point of confusion for Revit’s gbXML translations.Take a look at these two models. In both cases the overall size of the structure and the relative position of the building objects was unchanged, but in the first case the clerestory glazing has been represented by an object from Store Front Curtain Wall family ands in the second case it has been represented by an object from Window family.
When the Store Front Curtain Wall object is used in the same location it is ignored by gbXML translation and the host surface does not contain the opening child element associated with it.

Launch this VRML model file to highlight and examine its surfaces in order to visualize clerestory inconsistency.

In the second model I have replaced the Clear Story element with a window object and it has been correctly translates as the child opening surface to the hosting exterior wall

Launch this VRML model file to highlight and examine its surfaces and see that clerestory is reported correctly.

The recommendation of this finding is to use the Window Family objects as often as possible in order to represent the glazed openings in building skin, and the only modification that I would suggest is to modify the generic window family and assign height and width as the instance parameters. This will allow you to manipulate a stretchable element within the walls as a very good modeling alternative to Store Front style curtain wall.
It is worth mentioning that the first floor store front was in both instances reported correctly as 4 different glazed surface which also can be used as an additional argument to use the Window object , as none of the mullions are exported to gbXML, and the more analytical surfaces are pushed to GBS simulation site the more complex and slower simulation will be.
A very good reference for anybody that is building a model suitable for the preliminary energy analysis is the
GBS manual and following the best practice procedures that are outlined there one should, from the start, avoid building intricate models with complex skins, as well as most of the geometry such as overhangs, brise de soleil, or double skin facade.
In the next post I will explain how to modify gbXML file in order to compensate for Modeling Software shortcomings when shading elements are the essential part of a building envelope.

Monday, October 08, 2007

CompliCAD / BIM

This article is a bit on a cynical side, but maybe, just maybe the cynicism is what we need for a sober look at which path to take before a commitment to the change has been made.
Again, understand your process before is rendered obsolete!

CompliCAD by Scott Meckenzie

Tuesday, October 02, 2007

ACA - Ductwork - Part II

Even though there is an excellent tutorial on creating ductwork out of structural elements, posted by Archidigm, I could not resist and give ACA (former ADT) walls a chance to prove their versatility.
With little bit of profiling and sweeps manipulation, one can easily modify a wall style that allows for some rather convenient placement of the proxy ductwork within a BIM compliant model.
As with any other ACA object that employs curve liner shapes, its representational quality will greatly depend on FACETDEV variable setting.
Download the sample file and see if this technique could work for you as well. Needless to say that with some additional classification and the creative use of Property Set Definition, these ducts can go a long way.

Click on the image to launch Design Review

Even though there is an excellent tutorial on creating ductwork out of structural elements, posted by Archidigm, I could not resist and give ACA (former ADT) walls a chance to prove their versatility.
With little bit of profiling and sweeps manipulation, one can easily modify a wall style that allows for some rather convenient placement of the proxy ductwork within a BIM compliant model.
As with any other ACA object that employs curve liner shapes, its representational quality will greatly depend on FACETDEV variable setting.
Download the sample file and see if this technique could work for you as well. Needless to say that with some additional classification and the creative use of Property Set Definition, these ducts can go a long way.

Sunday, September 23, 2007

Revit – a "Shade" too green - Revealed !

Well the shades are still there but thanks to Revit’s management and development team, the explanation for their occurrence was given promptly. In this instance Revit’s team (I just do not like to call them the factory as in my view programming is anything but a metaphor for Modern Times), has proven once again that they pay the attention to their product and the people using it. So “Shades”, here we go. From now on you can think of them as a “negligible” artifact that is the result of overlapping polygonal geometry when host and hosted elements interact.

(image courtesy of AutoDesk)

Think of this “negligible” factor within gbXML file as your comfort level threshold when it comes to the accuracy of GBS simulation results. As illustrated these shade surfaces are formed from the centerline of Revit’s wall to the exterior surfaces of either walls or roof eaves.
Their depth depends on the construction type and the amount of overhang, meaning the thicker the exterior wall the deeper the shade surface, and the wider the overhang the larger area of that roof's surface will be designated as the Shade surface.

(image courtesy of AutoDesk)

Therefore the difference in the amount of applicable shading will be different with respect to the construction method as a 12” wide wall over 10 feet will produce an additional 5 SF of shading, and a 24” thick wall over the same distance will generate 10 SF of shading surfaces. For now, if you seek for a no questions asked simulation model, go ahead and get rid of all of the Shade surfaces that are not functional from the designer's perspective by manually deleting them from the gbXML file.The good news is that Revit's team is working hard to streamline the gbXML translation tool even more by increasing its accuracy and flexibility.
It is also important to emphasize the relationship between the Room object and its upper boundaries.
This subject is covered in
Revit’s MEP white paper and it deals with a limited range of roof forms and the required relationship with Room objects.
To make this long story short, one should ensure that the Room object’s upper boundary extends above the highest vertex of the roof. The analytical volume that is reported to gbXML file is not the one that reflects Room object's volume but the one that is encapsulated by the boundary surfaces of the adjacent building elements.I would encourage everyone to open their gbXML file and examine its content from time to time and verify that all of the model elements are correctly exported from Revit’s model. If reading XML is not one’s cup of tea, the GBS client has a convenient tool that translates the gbXML file into a VRML model and indicates the potential conflicting analytical surfaces. This model can be easily shared online and in order to visualize it the user should install a VRML viewer such as Cortona by Parallel Graphics.

In the next post I will illustrate some basic building forms and the best strategies for schematic design zoning in order to achieve quick and usable comparative results from GBS simulation.

Sunday, September 02, 2007

Revit – a "Shade" too green !

Over the last few years we have used a variety of the available tools to conduct basic energy analyses of our designs. At the scale of building components a valuable tool of the trade has been LBLN’s Therm 5.1 (6.1), which was able to relatively accurately predict the thermal transfer relationship among various building components and materials. On the whole building scale the two tools of choice were Ecotect and Green Building Studio.
Recently, due to its format’s legibility, it became evident that Revit Architecture has some issues when it generates the gbXML file.
The first one is that if a user attempts to poke through the Light Fixture schedule this somehow partially triggers Revit’s MEP mode where it starts outputting Light Fixture and Equipment Loads in a room, but does not assign value to those and they are being reported to GBS as zero values, making your building internal loads no believable.

The second issue that we ran into was the inaccuracy of the gbXML file in terms of additional building components being added by Revit. I am taking about “Shade” devices that are showing as part of the gbXML file for every Wall and Roof object within the Revit model. It is interesting that the same Object ID from Revit’s model is used on both Polygons describing Wall and Shade respectively.

As a result the output from your simulation can be skewed as being more or less energy efficient depending on the building’s location and construction method.
The only way to circumvent this problem is to manually open a Revit generated gbXML file and look for “Shades” that are not supposed to be here as the part of the original design. Identify them, delete them and rerun the simulation and compare your results.

Here is the example of what I am talking about. This extremely simple model where the generic 8” wall, Generic 12” Slab and Generic 12” Roof are used with the Room volume calculation enabled and with the Room object having enough offset to be picked up by Roof planes.

The output file was than examined and the intriguing addition of the addition surfaces is quite evident. The additional “Shade” surface type enumerators are not part of the original design as they do not relate to any “floating” wall geometry.

What is even more intriguing is that when Object IDs are compared throughout the gbXML file, one notices that a single Revit object was interpreted twice: once as a building object designated by surface type enumerator whose value = "Exterior Wall", "Roof" "Slab on grade" etc.) and simultaneously as the non design existent “Shade” object.
To check the validity of the object's ID number I have used the number from the same gbXML file to select an object within the Revit model.

In this day and age when so much focus is directed toward BIM compliant software ‘s ability to be used as an appropriate analytical tool it is quite disconcerting when these glitches occur. Most of the results that are obtained from these models might have embedded errors that were not design envisioned but software altered, and the confidence that architects can have in their design by expressing it in an quantifiable way should not be compromised by launching software that claims more than it can deliver.

Furthermore, it is high time for software developers to start thinking as architects and engineers do, and unlocking the potential that BIM has as the methodology should extend beyond visual aspects of those applications. A unified library of materials with their real physical properties including embedded energy, carbon content, and thermal conductivity coupled with the ability to quantify building materials in addition to the assemblies, should be top priority if any of these tools want to reclaim their analytical competency.

The conclusion is that when one accounts for all of the complexity associated with the realization of the built environment, we all have the responsibility to critically examine the tools and methodologies that software companies present as “their” best solution and maybe, just maybe this will make them think less about marketing and more about delivering stable and reliable products.

Monday, August 06, 2007

Ameri-CAD Aquired by ITW

Ameri-CAD, the company that has created one of the most comprehensive residential BIM solutions on the market, VisionREZ, has been acuired by ITW. This could be very good news and the validation of ACA as a viable BIM platform. To learn more about VisionREZ check out the following links;

Sunday, July 29, 2007

Building Performance Analysis and Carbon Footprint

Green Building Studio is launching a BIM platform independent training course focusing on hands on approach in integrating the existing available software within the context of Building Performance Analysis. The name of the course is “Carbon Neutral Building Design” and if you long to find more about it, the course outline is posted on their web.
I am really looking forward to this event, and just in case that any of ACA (former ADT, still can't get used to it!) users are wondering what happened to their gbXML plug-in, the word is out that it will be released in a couple of months.

Thursday, July 26, 2007

Where did BIM go?

At the center of SOM’s visionary design process was AutoCAD®. “AutoCAD was incredibly valuable, and not just from a final documentation standpoint,” says Frechette. “We took individual parts of the building, modeled them in 3D in AutoCAD, extracted the information, and imported that data into a variety of other programs for analysis. It offers a common language that can be used in so many different areas.”

Reed the entire article...

© Copyright 2007 Autodesk, Inc. All rights reserved

Thursday, July 05, 2007

Revit Architecture 2008 - Review is important for BIM vendors like Autodesk to continue to invest some of their resources into broader R&D efforts rather than on simply improving what they have developed so far. The latter is undoubtedly important for day-to-day usability but it is the broader research and development that will lead to real innovation and ultimately shape the future of BIM.

Reed the entire article

by Lachmi Khemlani, 27th of June 2007

Tuesday, June 12, 2007

BIM Buzz

Another unbiased article that tries to shed some light on the methodology whose definition is still quite illusive, Behind Building Information Modeling Buzz .

Friday, June 01, 2007

Nurbs Surface in Autocad Architecture

Approximating Nurbs Surface in Autodesk Architectural Desktop... the article was published in Hagerman & Co. Technology bulletin in June of 2005

Sunday, April 08, 2007

Learning how to walk.....

I would definitely recommend this article to everyone that contemplates their position and role in the brave new world of BIM. Nigel Davies is one of the very few people out there that manages to circumvent BIM hysteria and deliver a sober and measured view on how to adopt the new methodology while maximizing its capacity within the boundaries of one’s true need assessment...(Mis)understanding BIM

Saturday, March 17, 2007

BIM a porter

In over twenty years of implementing and using digital technology, both as an engineer and later as an architect, the most valuable lesson I have learned is the one of “critical practice”. Unfortunately, even though BIM as a methodology is nothing more than a transplant from more advanced areas of industrial production, it is truly amazing to see the extent to which acceptance, without scrutiny, is being preached over the last two years. Due to the nature of my work I happen to be more or less aware of the current status that BIM has in a large number of architectural firms of various size, and the datasets that are in circulation within those same offices, as well as in between different disciplines on the same job, are a far cry from being BIM compliant. Isn’t it high time to slow down and try to focus on core functionality and interoperability, versus creating this more than ideal picture of “shall” before “have”. Let us see a benchmarked project, completed and fully exposed in the public domain as a case study that can be dissected and scrutinized for the benefit of the entire AEC community. Implementing BIM should be a learning process that transcends the individuality that is still admired as a defining characteristic of any architectural office. Such methodology should create a solid foundation for not only more efficient design but also that which has achieved its materialization through iterative analysis and has proven the test of time. In today’s culture of blitz marketing and short lived commodities, it is hard to become a believer in “sustainable” when methodology itself has become prĂȘt a porter.

Thursday, February 22, 2007

Parametric Ceiling in ADT 2006/2007

Unfortunately I did not have the pleasure of attending the last AU for various reasons, of which being busy was the most important one, but a presentation handout was delivered to me by a colleague, titled Extreme Architecture.... Interesting concept, almost like Microsoft marketing Word for Extreme Poetry. I just hope that there will be some more thoughtful attempts to depict what we as architect can do when converting an abstract thought into a materialized reality, regardless to which tools we use.

Back on tangent.

Here is an example of a not so extreme but quite useful application of the parametric capability the ADT has. The anchoring tools in conjunction with walls, mass elements and grids will be used to create adjustable (parametric) coffered ceilings.
First I would like to begin by mentioning the AecCellAnchor command which can be used to distribute an AEC object by placing it within the AEC grid object's cells. This turns out to be a quite useful and obscure command that exploits the parametric nature of ADT 's database functionality by enabling the user to link object location and AEC grid location including spacing and scaling. After reading a really interesting tutorial by Archidigm on how to build a coffered ceiling by using the Curtain wall object , I had an opportunity to try this technique on a project with a beautiful cast in place concrete ceiling in an existing historic building. The Client interest in obtaining a rendering of the new program and depicting this ceiling as accurately as possible was essential for us to start thinking about the most flexible and fastest way to create and possibly tweak the new geometry.

The idiosyncrasy of the previously mentioned technique that did not work quite well in this particular case was the rather structured procedure for adjusting a curtain wall based grid to match the irregular grid of the existing building. And then this idea was born...

For a long time I have been using AEC anchor tools for controlled distribution of miscellaneous MV blocks, seating assemblies and parametric relationship between walls in ADT projects.

Combining AEC anchoring tools and extremely versatile Mass Object on non printable layer (s) via interference condition that can be applied to AecWalls became the standard for creating complex volumetric relationships between building skin, partitions and structure.

As this example was written for ADT 2006 it uses a variable with wall object in lieu of slab object that acquired interference capability in ADT 2007, but in 2007 version of this tutorial one can have a multi - material version of a coffered ceiling.

The first step is to create a new wall style and for the sake of this tutorial I
named it AecWallCeiling that should be associated with a new Wall Cleanup Style named AecCeiling.

If the ceiling in your project is at 9' create a wall style that has the Wall Baseline offset set at 9' and default wall height of 10'. When this is accomplished, place a new wall based on the previously mentioned style, in between the walls that are representing room's boundaries, and adjust its width to match the width of a room.

The next step is to create a mass object that will represent a "negative" of the that
particular coffered ceiling that you are working on. For this purpose I have created a relatively simple mass object an in order to control its polygon count and ability to approximate smooth radius I have adjusted the FacetRes Variable to 0.0625.

When this is completed go ahead and align a parametric AEC grid with the location
(height) and boundaries of AecWallCeiling Object.

Now before you anchor the Mass Object negative to the grid, let's stop for a moment and think what could be an added bonus feature of this technique. AEC Grid has the ability to scale the AEC Mass object within the boundaries of the each individual cell, but what if we intend for this object to be just a little bit more interactive and grid independent, let's say that we would like to change its dimensional characteristics and appearance and propagate that change through each object instance within that AEC grid defined pattern.

Here is the point where ADT can surprise you again. Its ability to create a reference of an object in a similar way to VIZ or Max , is quite a tool in your arsenal of ADT skills, and especially when you work with multiple repetitive objects, like trims and moldings.

Locating Mass Element Negative in respect to the grid.

Go ahead and type AecEntRefAdd, use the center (m2p) of your mass object as the insertion point and create a new reference object. This new object will now have to be associated with the AEC grid in the following manner. Type _AecCellAnchor and first select the reference object that will be anchored to a cell within the layout grid, and then select the grid to which we will anchor this object. While the command is still active and after the first cell has been populated, type "C" for copy and again select the the same reference object and then the grid. When prompted whether to skip those cells that are already populated, chose Yes and let ADT will do the rest.

Place the "negatives" in the desired location within the AEC grid. Select the wall
object that is being used as a ceiling slab, chose the interference option from the context short cut menu and select all of the "negative" references of the original mass object. Turn the nonprintable layer that is hosting "negatives" off. The layer approach was the quickest solution for the sake of this tutorial. Better results can be achieved by creating a Mass Object Style whose corresponding material will be invisible in reflected ceiling plan or model view, but that is a topic for another tutorial.

I need to mention that all of these tools have existed as the core functionality of ADT in one way or another since version 3.3, but like with any other application it takes some time and dedication and some creative thinking to make them work. Now if you think that your project requirements have outgrown the capacity of the software you currently use, think again and see if there are some other features or techniques that were neglected over time that are worth implementing, before your reseller tells you that it's shopping time again.

This is the rendering depicting the effectiveness of previously mentioned procedure and if you think that this example is of any use, feel free to download this sample file and test it on one of your projects.

Until next time….