dRofus and Revit differ in the methods they use to determine which Family Instances are located within which Room. dRofus uses the position of the Family Instance "Room Calculation Point" of the Family to determine if it falls within the boundaries of the Room. Because of this difference of behaviors between Revit and dRofus, there may be discrepancies between the schedule :
Schedule of Family Instances in Rooms as reported by Revit
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dRofus listing of Family Instances in Rooms within the "Items in room", "Items in level/model" or "Items in level/model (spaces)" dialog windows.
For example Example: if the "Room Calculation Point" of a Family Instance falls within a bounding wall then it is not counted as it falls outside of the Room boundary. This method of calculation
Set Room Boundary Tolerance
Room Boundary Tolerance can be used to advantage where there may be an item located outside the Room (eg: LASER IN USE sign) which would still need to be considered as belonging to the Room. The Family Type could be modelled with a Room Location Point that extends to within the Room.
In the Options you can adjust the settings to consider Family Instances that fall outside of the Room boundary by entering a tolerance value (in Feet) against "Room boundary tolerance":
include objects in Room that are located outside the room.
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Step 1. Open “Options”
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Step 2: Set Tolerance measured in feet.
a. Room ceiling tolerance:
Set the boundary tolerance for detecting ceilings and the Items within or above the ceiling.
b. Room floor tolerance:
Set the boundary tolerance for detecting floors and the Items within or below the floor
c. Room boundary tolerance:
Set the boundary tolerance for detecting walls and the Items within or outside the walls