So you completed the SketchUp Plugin process and are ready to export. You click the export button and get this error: undefined method '+' for nill:Nilclass (below), what do you do next?
This error is the result of geometry being unable to separate elements into the required fields of the geometry page. To troubleshoot, first check for non vertical (upright) geometry in the exterior walls and windows layer. Geometry in these layers are immediately separated by the plugin into the 8 cardinal directions (N, NE, E, SE, S, SW, W, NW) fields. However, when horizontal geometry like window frames and wall edges end up in these layers, they crash the export command because they have no cardinal direction inclination. See example below of a layer wall in SketchUp which may cause the export command to error out. Users can decide to delete or move these elements to the roof/floors layers, or place them in a non cove.tool generated layer.
If your layers do not contain the problematic geometry as stated above, then the second most likely situation is reversed faces. Using the "Reverse Faces" button in the cove.tool plugin tool bar, activate a custom view style which will apply a high-contrast material property to all the front and back face building geometry in the SketchUp window. White surfaces representing front facing planes and green surfaces represent back facing planes. It is crucial to have all building envelope geometry displaying front facing surfaces outwards, and all horizontal plane geometry having their front planes facing upwards. If your export command gave the error at the top of this article, it is most likely your floor objects are facing downwards which would be incorrect for creating the energy and daylight model in cove.tool. Select incorrectly facing geometry in order to reverse them, then when done attempt exporting again. See examples below.