Question-and-Answer Resource for the Building Energy Modeling Community
 | 1 | initial version |
When working with thick wall plans you are probably fine if you pick outside, inside or middle, but for best practice, you should use the outside edge of exterior walls, and the middle/centerline for interior walls. Here are links to two videos on the subject. While most people don't think about it this same logic would apply to floors and ceilings, but it is rare that I have ever seen a model where the interior floor location represents the middle of the floor construction, typically I see the finished floor as the modeled location, probably so the relationship between the windows/doors and the floor are in sync.
This video shows you how to model from plans
And this video continues on the same model to model fenestration from elevations
