ACA: Interference Condition vs Subtraction in Area Calculations

For all of the work I have done with the Schedule Feature of AutoCAD® Architecture over the years, I have not done much with trying to produce accurate Space Schedules, particularly where Interference Conditions and/or Linework Subtraction is involved.

A question came up the other day about this, and I was surprised to learn that even though an Interference Condition “removes” any visible Hatch Component from a Space in a plan (Top) view, it does not have any effect on any of the reported Area properties of a Space. I did discover that using the AecLineworkSubtract command, the area removed does affect the reported area. I cannot speak to the reasons behind this, but given that an Interference Condition (SpaceInterferenceAdd command) only affects the Floor/Floor thickness of a Space, whereas the AecLineworkSubtract command removes the projected 3D volume of a selected 2D Polygon from bottom to top of a Space, perhaps that would be considered to be “by design”.

Some additional…
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