I use the Cut List plug-in and have just discovered that it gets its knickers in a twist if you have a model (like my lantern) with a component that is on the diagonal like a hip rafter. Cut List seems to give the dimensions of the bounding box (if that's the right word) rather than the actual component which goes from the top of one corner of the box down to the opposite diagonal bottom corner.
Of course, it could be down to me using an out-of-date plug-in and/or version of SketchUp !