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Base surface does not surround subsurface

asked 2015-10-09 13:46:05 -0600

updated 2020-01-26 11:49:28 -0600

I'm working on an OS/E+ model that has some tricky geometry with many non-rectangular and non-vertical walls. I have punched windows located on these surfaces and I'm receiving the following warning(s) on many of the subsurface windows...

** Warning ** Base surface does not surround subsurface (CHKSBS),

The warning is then followed by either Overlap Status=Partial-Overlap or Overlap Status=No-Overlap

I am still able to run a successful simulation and the results do not appear to be way out of line. Everything appears correctly in the SketchUp rendering as well.

Does the warning above impact the simulation in any significant way?

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Comments

I expect this is just a rounding error creating an inadvertent warning. To confirm the surfaces are where they are expected you could use the view model or view data measures in the OpenStudio applciation, or export a DXF from EnergyPlus.

  • When you view the model in the SketchUp plugin do you see the surfaces in SketchUp or does the warning prevent them from being drawn?
  • Do you have any doors, or do you have any windows that go very close to the edge?
  • Did you draw geometry in SketchUp or import from another tool?
David Goldwasser's avatar David Goldwasser  ( 2015-10-09 15:48:27 -0600 )edit

The SketchUp plugin shows the surfaces correctly and there are no input file errors and warnings when opening the model in SketchUp. I also ran the 'view model' measure as suggested and the surfaces show up in the web browser view of the HTML.

I do have windows (subsurfaces) that touch 1 edge of a surface in some situations.

I imported 3D DWGs in SketchUp and traced the necessary elements in SketchUp.

Lyle K's avatar Lyle K  ( 2015-10-09 16:15:26 -0600 )edit

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answered 2015-10-12 10:52:04 -0600

The OpenStudio SketchUp plug-in is sensitive to windows sharing an entire edge (or corner) with their base surface because SketchUp divides this into two faces instead of one face with an inner loop. However, this is just on the input side and it sounds like you are not having an issues there. This might be an EnergyPlus issue, OpenStudio and EnergyPlus do not share geometry processing routines so it is possible that EnergyPlus has an issue with windows on slanted surfaces. I'm not aware of any issues currently and I'm not sure what the implications on simulation results would be, someone from the EnergyPlus team should chime in here.

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Asked: 2015-10-09 13:46:05 -0600

Seen: 813 times

Last updated: Oct 12 '15