It may be caused by stretching 1 duct to create the next
try double clicking on the duct to open up the edit part take-off page, and then close it down and see if that fixes it
does it still show as o.oo area?
its a common issue when creating straight ducts by stretching them and it wont show any area until you open the part up or change the specifications.
there is a post previously regarding this which explains it better than me
hope that fixes you issue
Thx
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