Floor Finishes with Threshols from Rooms

Revit
,
12
  1. Get a location line of the wall, get it’s total witdh.
  2. Build wall lines, using location line and offset (wall’s width)
  3. Get facing vector of the door.
  4. Project points to wall line according to facing vector of the door.
  5. Build lines from points.

In short, you just move thershold line to opposite wall’s line, using door’s facing vector.