Wall area for a particular zone?

[Anonymous]

hi all,

i've been reading up on schedules/element info and zones but can't seem to get a particular set of data without some major workarounds.

there is a lot of info on this but i'm still not sure whether what i want to do is possible or not - apologies in advance if this has already been discussed.

i would like to do the following (please see attachment): for the highlighted zone (shown green) i select Element Information. The info is set up so it displays the Wall Surface (yellow highlight). I assumed that this number would be the area of the walls 'touching' (surrounding) the zone (based on zone level and height) less the area of all the openings, but after calculating the actual surface area, the result is very different. I also notice that if i change the Zone Height, the Zone Volume updates but there is no change in Zone Wall Surface.

So my questions are:

can i determine the surface area of the walls surrounding the zone (based on the level and height of the zone)?

how does Element Information calculate the Wall Surface area?

TIA

[Karl Ottenstein]

Derek wrote:
can i determine the surface area of the walls surrounding the zone (based on the level and height of the zone)?

how does Element Information calculate the Wall Surface area?

Hi Derek,

If you have used one of the auto-fitting zone geometry methods, and updated the zones to fit any wall editing - then any wall that touches the zone is included in the area value shown. The height of the zone does not affect wall surface, only zone volume.

Any openings that I insert subtract the correct amount of surface from the walls.

The wall surface issue is an interesting one now that we have had multistory walls in AC and the floor plan cut plane for a few versions. It seems to me that one might want an option to include only the surface that touches the zone. (In the 'old' days, a wall only showed up on one story, and so it could not be part of a zone on another story anyway.) Lacking this, it is too easy to accidentally include the same wall surface multiple times in a schedule.

Cheers,
Karl

[Anonymous]

thanks for the reply Karl.

Karl wrote:
any wall that touches the zone is included in the area value shown. The height of the zone does not affect wall surface, only zone volume.

so the only way to get the correct surface value to show is to adjust the height of the walls to the zone? kind of defeats the purpose doesn't it - or am i not using this feature properly?

for example - i'm trying to automate the calculation of quantities of plasterboard required for a house.

an 'easy' way to do this would be to assign a zone to completely fill each room and then create a schedule to display the 'side surface area' and the 'top surface area' and then deduct the area of any openings and add it all up. i can almost do this but unfortunately the schedule adds up the entire surface area of any wall touching the zone even if the wall is only partially touching (weirdly, the wall area IS correctly deducted if it is longer than the zone, but IS NOT deducted if it is taller than the zone). so, to have the schedule work the way i want it to, i would have to adjust the height of all the walls to match the height of all the zones.

this would be an ok workaround in theory, but unfortunately, working this way means that all my elevations and renders will look wrong because they have lines/contours on them where the different height walls meet!

i'm only just starting to learn schedules now though, so i hope there is a better solution.

Karl wrote:
It seems to me that one might want an option to include only the surface that touches the zone.

i guess all that is really needed (in my case at least) is the ability to calculate the surface area of the zone itself (top, sides, bottom) disregarding the walls completely. the schedule can already calculate the area of any openings so deducting these from total surface area would be a simple calculation.

[Karl Ottenstein]

You do not have to do any math yourself - ArchiCAD does subtract the area of openings from the surface area.

But, the problem is the wall height vs the zone height as you note. Depending on how your building is framed, the result will be close (off by the thickness of the ceiling gyp). If you have a suspended ceiling, or tall walls with floor systems attached to ledgers, or other things going on, then the easy way won't do the trick.

You can use complex profiled walls and component lists to generate gyp only where it is needed and get the correct gyp surface numbers. In principal. But, perhaps not by zone. Have not tested it.

Karl

[Anonymous]

in the end i used the info available and exported to excel for final calcs and managed to get everything i needed quite quickly. not perfect but much better than calculating from scratch.

however, it would be nice if the schedules could calculate the surface area of the sides of the zone (less the openings). is it worth putting this in the wishlist?

[Erika Epstein]

Derek wrote:

however, it would be nice if the schedules could calculate the surface area of the sides of the zone (less the openings). is it worth putting this in the wishlist?

You can already do this. Set up the schedule based on zones, trim zone(s) appropriately. There is a parameter that will give the the net surface area of the zones i.e. what matches the the wall area less openings.

[Anonymous]

Erika wrote:
There is a parameter that will give the the net surface area of the zones i.e. what matches the the wall area less openings.

Erika, i believe we discussed this above with the conclusion that the surface area of the zone includes the area of any wall touching the zone even if these walls are higher than the zone that they touch (e.g. the zone is 2.4m high, but is within a room that has an external wall with a height of 2.65m (wall + floor thickness). in this case the surface area of the sides of the zone will be overestimated.

or are you saying there is a way to get just the surface area of the zone sides?

[Erika Epstein]

Yes. Create a schedule based on zones, not walls. The wall surface parameter will give you the surface of zone abutting a wall less openings.
In my example I created a simple box. I dragged a copy. To one I added doors and windows. The schedule shows the actual wall area less the openings.

[Anonymous]

Erika, take a look at the attached.

i've made the example as basic as possible to make my point. there are 4 walls. each INTERNAL wall is 1m long x 1m high, so the total wall surface area is:

1m x 1m x 4 walls = 4m2

the zone i created is within the walls but is half the total height (the zone is 500mm or 1/2m high) so the surface area of the zone (sides of the zone) should be:

1m x 0.5m x 4 walls = 2m2.

however, as you can see, the calculated area is 4m2 - the total area of the walls touching the zone. this is the problem. AC does not trim the height of the wall to the zone. the same result comes out of the schedules. i used Element Info because it's quicker for this example.

even if i trim the walls to a roof which is at the same height as the top of the zone, the zone still calculates the total height of the untrimmed roof (see attachment in next post)

does it work for you?

[Anonymous]

even with trimmed walls, the calculated surface area is still 4m2. these walls are now only 1/2m high x 1m long so the toal area should be 2m2.

the UNTRIMMED height of the wall is 1m and this is the height used for calcs...