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Zones gross and net


I do a lot of work early on when it comes to working out how many apartments we can get on a site with zones. We are of course always asked for net and gross areas. We can get the gross external areas easily of course from the zones, but does anyone know how I can get gross internal areas (GIA). All I need is to be able to take off a notional external wall thickness of each zone to give me the gross internal area. I can see you can reduce by a percentage but that just doesnt seem accurate enough for my liking.


Barry Kelly

I assume you want to do this without actually modelling the walls?


If so then maybe this will work - I have not tried anything like this.

Maybe properties with expressions can work.

Create a property that multiplies the perimeter of the zone by a wall thickness and deducts it from the zone area.

This assumes all zone edges will have the same wall thickness.


If they don't then the only way I can think to do it accurately is to model the wall.

Then you will have a gross and calculated area automatically for the zones.



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Thank you - I will try that. I'm not great at expressions so I might come back with a few more questions!

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