I use MoI quite often to work out tricky constructional details. Here is an example where I was trying to figure out exactly how the wall cladding would meet the roofing in a timber framed building and how the junction would be made water-tight. I was then able to import the model into my arch program and use it to create line drawings (although that part was not so straight forward).

This is the less glamourous side of architecture, but MoI is very useful to solve such problems.