There are a few situations where creating windows and then surface matching would be problematic
- If you plan to use a WWR script/measure vs. manually drawing then you really want surface matching done first so the script/measure can identify interior vs. exterior surfaces.
- If you are going to have interior sub-surfaces and you use the measure based intersection vs. the SketchUp plugin then you will want to intersect/match and then add the interior windows. The measure based intersect doesn't find sub-surface intersections. Only base surfaces.
Can you provide some more details on the performance issue doing your full model vs. the test?
- How many spaces did your test model have?
- How many spaces is the full model? I would expect a model twice as big to take more than twice as long to intersect.
- How long did you wait for the full model intersect to run? And did you get any feedback while it was working?