How to see if a door faces outside

I'm working on a pathfinding program in revit. In order to get this to work I need to know what doors face the outside, in order to find this I have several ideas but am unsure how to get any of them done.

1 something with topolegy and looking at how close the topolegy is to the door, anyone know if this can be done?

2 something with looking at every wall and every door, won't this be slow?

3 some secret property I have yet to find in doors.

Solution

I would say that it depends on whether you can demand specific "IsExterior" kind of parameters be applied to the door (or not). Obviously that approach would work.

Beyond that, the other approaches might be:

You can look at the Door.FromRoom and Door.ToRoom (by phase), and see if it only has a room on one side of it
- This presumes that all rooms are modeled.
- This presumes that certain "outdoor" rooms, like "Deck", "Patio" are not modeled.
You can look at the geometry, intersecting the door vector with other walls in the model. The performance varies. Sometimes it's not as bad as you think.
- This might get into how to properly handle linked models (and what geometry is in those linked models - core/shell, surrounding buildings, etc).
- The simple shapes are easy, but more complex cases (courtyard, alleyway, etc) can be complex.

Good luck, I'd love to know what you come up with... -Matt