I would place a sphere into the model location. then run toolscheckinterference2.
it will get you the following results.
Array of components where interference has been found
Array of faces where interference has been found
swAssy.ToolsCheckInterference2 nSelCount, (vCompArray), bCoincidentInterference, vIntCompArray, vIntFaceArray
As I understand in your method I can use not only sphere but also cube. If I am not mistake this method has error on height of sphere.