Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
Since the surfaces and subsurfaces in EnergyPlus are defined by using the four corner vertices, it is very easy for the subsurface (doors and windows) to not be on the same plane as the surface (wall, roof or floor) that they are supposed to be part of. The outward facing angle is the imaginary vector that points outward from the surface or subsurface. If the subsurface and surface are on the same plane, the outward facing angles would be equal. The warning message is saying that these angles are not the same.
The second portion of the warning message is saying that you can put the Output:Diagnostics object in the file with the first field being Display Extra Warnings. This will give you a little more detail in the warning message and name the surface and subsurface that are causing the problem along with the title and azimuth angles for each surface. This will help diagnose the problem.
As Amir suggested, you might want to use a tool to visualize your IDF file such as the Legacy OpenStudio plug-in to SketchUp.
