Friday 21 September 2012

Lighting Analysis - The great BIM interoperability Debate!


With the project focus on BIM, this provided an interesting opportunity to look at the issue of what software is classed as BIM. As most know, Ecotect is BIM and very typically used to calculate daylighing analysis, however 3ds Max is not. This presented an opportunity to compare the two processes.



Let me first start by explaining that there are essentially two ways of going about this proccess of using ecotect, the first ( which I took and have documented) is to import your file as a DXF into ecotect. This proccess isnt BIM as exporting the project as pure geometry looses the vital information essential to BIM. I learnt this the long way.


This proccess of exporting as DXF had another major implication- many faces = complex + really really realy slow calculation, I mean really Slow! All of this is without materials as well- so the accuracy of this analysis is down the drain- or is rather a study of light levels based off uniform material surfaces..








 The second second proccess ( and essential the correct proccess ) is to Export as a GBXML file which uses room data allocated in revit to calculate basic room geomerty. This also exports basic information such as object data and awareness ( it knows a wall is a wall, and glass is glass). However this is as detailed as it gets, with some vital geometry such as working planes ( desks etc) omitted. This means it has limited capabilities in the later design stages.  It also fails to translate any more detailed material information which poses me to ask the question of how well this integrates with the BIM process if it only brings across basic information?
In addition to this, the program is quantitative based with the only way to acquire qualitative data ( basic at the most) is to import to radiance.

This brings us to the second analysis method used for the project- linking into 3ds Max Design.


 What is great about using 3ds Max Design is its accuracy in both a Quantitative and Qualitative manner; it can measure Illuminance and Luminance using false colour images as well as using the lighting analysis assistance to measure lighting levels at any point in physical space using the light meter tool.




 3ds Max Design calculates all this from material data carried over ( and updated by a linked file) from Revit meaning much more accurate results than Ecotect. In addition to this, photometric data is carried across for artificial lighting analysis. 



 Measuring light levels in the apartments



 Measuring lighting levels from Atrium 


 Illuminance Psuedo Colour Output Image



As mentioned previously, Max also measures light in a qualitative manner based of the material selection made in Revit, including surface properties such a reflectance, colour and transparency, all critical to designing accurate task lighting.

After comparing the two, the question must be asked, could 3ds Max be classed as BIM considering it contains the same amount of data as an ecotect file, while providing a more detailed analysis and using a constant link to the revit project? If not what is needed for this to become BIM integrated?



No comments:

Post a Comment