Calculate correct room area under roof

[jekabs.smits]

How to calculate room area that is below sloped roof with ceiling height at least 1600 mm? Do I need to draw room separation lines manually or is there a better option?

Thanks!

[barthbradley]

Yes. Use Room Separation Lines divide it up it need be.  

[barthbradley]

Area? I assume you mean Floor Area in Attic.  Same deal.  

[Anonymous]

Give Roombook, Buildbook and Areabook extensions a shot. It will help you out greatly to achieve what you want and give you great control over the process.

[ToanDN]

Set the level's room computation height to that line and set room
computations to area/volume.