In models grid lines are used to align walls and other element. This Add-in searches for all grid line angles and check all elements if they are parallel or orthogonal to a grid line. If not the element is displayed in a list and if the user double clicks on the element, the element is highlighted in the model. This element allows a designer to quickly identify problems in the model even if the model has a complicated grid structure.
This plugin is also for sale, use the download link below for a trial version. For licensing details contact me at tom@tnux.net.