New Member
Posts: 1
Registered: ‎04-02-2012
Message 1 of 3 (354 Views)

Rooftop PV assessment

354 Views, 2 Replies
04-02-2012 11:01 AM

Hi everyone


I have a .dxf file of a city I am examining.


I want to assess the rooftop potential for photovoltaics using Ecotect for all the buildings of this city. Therefore all I am trying to achieve is effectively a map of this city with the layout of the rooftop solar potential. Keep in mind this city has several thousand buildings in it!!


I have tried several of the tutorials but am still confused and have not managed to do this and not even sure of the correct method of how to do this, also I dont know whether the data I have (.dxf file of city) is sufficient for what I want to do!


therefore I was hoping if anyone has done something like this before, a solar assessment (just for the solar as a resource and not further into  energy generation etc) of all the rooftops in a city.

Hope my question is clear



New Member
Posts: 1
Registered: ‎05-11-2014
Message 2 of 3 (132 Views)

Re: Rooftop PV assessment

06-01-2014 07:57 PM in reply to: andreas.alkiviades



당신은 나에게 DXF 파일을 보내 ???


내 이메일

Posts: 155
Registered: ‎04-23-2010
Message 3 of 3 (124 Views)

Re: Rooftop PV assessment

06-04-2014 04:04 PM in reply to: andreas.alkiviades

Hi Andreas, 

Yes your question is very clear.

I was actually involved in rooftop solar radiation assessment about a decade ago, using image recognition software to pick up roof areas from aerial photographs and sending that to some solar radiation software...

You can do it in Ecotect, without too much assles depending on your dxf model.


1. make sure your model is clean - look at it in side view and select all the walls and makes sure they are assigned as walls and their surface normals pointing out.  Do the same for the floors (sn pointing down) and roofs (sn pointing up).  This is to make it easy for you to select only the objects you want (roofs).


2. Once that is done, go to the select menu > By Orientation > Up ( note that you can also select By Element Type > Roof) as per #1 above.


3. You can now run the Solar Access Analysis under the Calculate menu. I would select Incident Solar Radiation > For Specified period (year) > Average Daily Values > Only use selected objects > {Perform Detailed Shading Calculations > Low Surface Sampling, fast calculation and Medium Sky subdivision for starter.


You have so many roofs that it might be just accurate enough for your project to have the calculations done on a per roof object basis as outlined above.  If larger roofs were to be analyzed at a more descreet level (more accurate but much longer calculation time), you could subdivide the geometry of these roof using the Modify menu > surface subdivision option.  But for an entire city, that would not be time efficient.

Run it as per above; if it does not take too long to calculate, you can increase the Surface Sampling to increase accuracy - instead of looking at a single point in the middle of your roof objects, the calculation will average over several points calculated on that object.  Of course it will take much longer to calculate...


I hope that helps.



Autodesk Ecotect Support Specialist
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