[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[EnergyPlus_Support] IFC to IDF, Geometry, Relative coordinates



I wanted to see how IFCtoIDF performs, so I drew a small building and tried to write extra parameters for EnergyPlus run. I have the following results.  


Description of the building:

Origin of the building is at (0,0,0) in line with True North. Dimensions are: 6m (inclusive), 6m (inclusive), 2.7m(Height). Inclusive means that the dimension is from one face to the opposite one. No System is defined at the moment. I am interested to see how Geometry is transferred.



Drawing done in ArchiCAD v7.0 -> File saved as IFC 2.0 -> IDF file written via BS-Pro IFCtoIDF utility->Simulation ran in E+ to see DXF file.



DXF Output file looks like figure 01. Please note that, yellow line is for roof slab outline, Gray is floor slab, Green is wall and Turquoise is for windows. From first observation it seems that –



Figure 01 – DXF output from IFCtoIDF after E+ Run.

a.       Walls are not connected but have an offset of 0.19m (Half the width of the Wall – 0.38 m).


                  Will that be a problem in E+ simulations, if walls are not connected? There’s a gap of 0.19m between walls and floor/ roof. My understanding is that, EnergyPlus is not like nodal simulation (like CFD), so it probably takes in only Area and Volume to calculate. In this case it does not matter if the walls/ slabs are not connected to each other. Am I right?

NOTE: I tried to define zone in different ways (ArchiCAD has 3 ways to define a zone) – Every procedure gives me the same result.


b.       If you take a closer look at figure 2 (bit rotated in AutoCAD to view the triangulation), you will see that both the slabs (floor/ roof) are triangulated instead of rectangular profile.


Is that a glitch in BSPro/ IFCtoIDF? Just curious. Did anybody face similar problem?

Figure 02: Rotated using 3D Orbit in SW Isometric view. Note the traingulation


NOTE: I guess, BSPro took wall centreline (cL) as the wall plane. But zones are created from inside dimensions of the wall.


I have corrected the coordinates (vertices) manually so that it looks like figure 03. Well, changing tens of coordinates for this file was tiresome but possible. What if – I have a big building, consisting of a number of zones and hundreds and thousands of vertices?


Figure 03: Vertices are edited manually so that the walls and slabs are all connected.


Will I have any trouble if I use the IDF file (figure 01, 02 - without any editing) and use it in simulation/ Do I have to edit the vertices so that they are connected?


Thanks in advance.




Monjur M Mourshed


Informatics Research Unit for Sustainable Engineering

National University of Ireland CorkIreland.

Web:   http://www.ecaad.com/monjur


Email : m.mourshed@xxxxxxxxxxx




Yahoo! Groups Sponsor

To unsubscribe from this group, send an email to:

The primary EnergyPlus web site is found at:

The group web site is:

Your use of Yahoo! Groups is subject to the Yahoo! Terms of Service.

SPAM: ------------------------ Spamnix Spam Report -------------------------
SPAM: Spamnix identified this message as spam.  This report shows which
SPAM: rules matched the message and how many points each rule contributed.
SPAM: Content analysis details:   (5.3 hits, 5 required)
SPAM: SMTPD_IN_RCVD      (2.1 points)  Received via SMTPD32 server (SMTPD32-n.n)
SPAM: FORGED_RCVD_FOUND  (0.0 points)  Possibly-forged 'Received:' header found
SPAM: DOUBLE_CAPSWORD    (1.1 points)  BODY: A word in all caps repeated on the line
SPAM: SPAM_REDIRECTOR    (1.7 points)  URI: Uses open redirection service
SPAM: MAILTO_LINK        (0.8 points)  BODY: Includes a URL link to send an email
SPAM: WEB_BUGS           (-0.4 points) BODY: Image tag with an ID code to identify you
SPAM: --------------------- End of Spamnix Spam Report ---------------------

Email file not found:
Email file not found:
Attachment not found:
Attachment not found:
Attachment not found:
Attachment not found:
Attachment not found:
Attachment not found:
Attachment not found:
Attachment not found:
Attachment not found:
Attachment not found:
Attachment not found: