ElumTools creates a 3D view in every project called the ElumTools_WorkingView.  When the Filter by View Visibility setting is set to True, ElumTools will only consider elements which are visible in the ElumTools_WorkingView.  When 'Filter by View Visibility' is set to 'False' all elements which intersect the calculation volume (Room, Space, etc.) will be included, regardless of its visibility (in any view).

Here is how to take advantage of "Filter by View Visibility".

1. Go to the ElumTools Settings and set Filter by View Visibility to True.

2. Locate the ElumTools_WorkingView and hide unwanted elements using any method. This will exclude them from the calculation as long as the Filter by View Visibility setting is set to true.  Modifying the Visibility Graphics settings of the ElumTools_Working View can be an easy way to exclude entire categories.  

Also see this blog post for some alternative work-flows.