#36 Error with subsurface sharing outside edge with its base

[Peter Ellis]

ERROR:
ArgumentError
At least three points needed to fit a plane

BACKTRACE:
E:/Projects/Development/OpenStudio/application-SU7m1/Plugins/OpenStudio/lib/Geom.rb:334:in `fit_plane_to_points'
E:/Projects/Development/OpenStudio/application-SU7m1/Plugins/OpenStudio/lib/Geom.rb:334:in `plane'
E:/Projects/Development/OpenStudio/application-SU7m1/Plugins/OpenStudio/lib/Geom.rb:300:in `normal'
E:/Projects/Development/OpenStudio/application-SU7m1/Plugins/OpenStudio/lib/Geom.rb:452:in `normal'
E:/Projects/Development/OpenStudio/application-SU7m1/Plugins/OpenStudio/lib/interfaces/DrawingUtils.rb:49:in `detect_attached_shading'
E:/Projects/Development/OpenStudio/application-SU7m1/Plugins/OpenStudio/lib/interfaces/DrawingUtils.rb:42:in `each'
E:/Projects/Development/OpenStudio/application-SU7m1/Plugins/OpenStudio/lib/interfaces/DrawingUtils.rb:42:in `detect_attached_shading'
E:/Projects/Development/OpenStudio/application-SU7m1/Plugins/OpenStudio/lib/observers/SurfaceGroupEntitiesObserver.rb:45:in `onElementAdded'
E:/Projects/Development/OpenStudio/application-SU7m1/Plugins/OpenStudio/lib/observers/SurfaceGroupEntitiesObserver.rb:22:in `initialize'
E:/Projects/Development/OpenStudio/application-SU7m1/Plugins/OpenStudio/lib/AsynchProc.rb:13:in `call'
E:/Projects/Development/OpenStudio/application-SU7m1/Plugins/wxSU/lib/wxruby/lib/wx/classes/evthandler.rb:133:in `acquire_handler'
E:/Projects/Development/OpenStudio/application-SU7m1/Plugins/wxSU/lib/wxruby/lib/wx/classes/evthandler.rb:133:in `call'

Steps to reproduce:
1. Draw a rectangle on the ground.
2. Draw a trapezoid on the south side of rectangle that completely shares the south edge with the base surface.
...OS identifies the surface as a window.
3. Erase the south edge so that the window is erased.
4. Reconnect the south edge to close the subsurface again and ERROR.

Also works on walls, but the subsurface must completely share one edge with the base surface.
Does not happen for subsurfaces that only share a portion of the outside edge.

It appears that the newly closed subsurface is being drawn inside out.