Calculate using expression; Zone - columns

[dominicus]

Hi,
In Finland we have a regulation to be able to deduct certain types of columns from the main area (m2)
The main area is calculated using a Zone that extends from the outer walls inner surface 250mm - so you have to draw the Zones by hand.
We use these zones to calculate the overall area/floor

I want to create an expression that deducts certain columns from the specific Zone

I have made an expression using the "zone area" - "column area" but it does not produce any results.
What am I doing wrong?

To make it easier I have chosen to show only the layers showing the specific zones and the specific columns
(and to make the calculation faster also - right?)

And to make this more difficult - can the expression be written to deduct only the columns inside the Zone parameter? - not a necessity but would be cool

Thanks,

Dominicus


PS. Archicad 22 latest build

[felcunha]

Hello,
You can make a solid operation to subtract the columns you want from the zones.
Therefore your net, reduced and calculated area will take this into account.