topic Re: How to calculate areas of the partition walls for the bill of quantities in Modeling

How to calculate areas of the partition walls for the bill of quantities

Isaac Newton — Tue, 09 May 2023 12:19:39 GMT

Good time of the day, gentlemen.

I'm trying to create a schedule to determine the areas of the interior partition walls. I need that for the German so called "Leistungsverzeichnis", i.e. the bill of quantities. There are special rules in Germany for calculating wall areas for the bills of quantities. For an instance the openings smaller than 2.5 square meters should be ommited, and the wall area should be calculated as if it didn't contain that opening. These rules, I believe, are listed in the set of rules for calculating wall areas in ArchiCAD:

It's not quite clear to me what does "conditional" mean in those rules though. There are lots of various parameters to determine the wall area in the schedules, but I'm not quite sure which one I should pick:

Most of all it's not clear to me what's the difference between "(conditional)" and "(brutto)".

And it's also not quite clear to me what part of the wall does the schedule calculate. According to the German bills of quantities rules, it's the exterior wall area that should be calculated. That means that on the corners the walls should always be measured on the longer side:

Is there a way, however, to make sure that the schedule would always recognise that the exterior side of the wall is the one with the longer linear measurements? Or, in case if the wall was created the way that is shown on the picture above, the schedule will calculate it's area along the shorter side?

Also, if I select the brutto exterior wall areas as a parameter in schedules, it seems that it also calculates the parts of the walls that intersect the massonry exterior walls:

Therefore I'd like to ask whether it's absolutely certain that no such things happen when I select the conditional parameter?

Re: How to calculate areas of the partition walls for the bill of quantities

Stefan Videnov — Fri, 03 Mar 2023 08:58:20 GMT

Hi,

You already have the conditions set up so it seems like you need
Conditional Surface Area on the Outside Face

These 2 links will help you understand how the parameters work:
https://helpcenter.graphisoft.com/user-guide/76908/
https://helpcenter.graphisoft.com/user-guide/136662/

Lastly, It might be a good idea to do small test in a separate file.
Model a few walls and include all the tricky aspects of your main model - connecting walls, smaller and larger openings, etc and calculate the area manually. Then you can check which parameter gives you the same value.

Good luck!

Re: How to calculate areas of the partition walls for the bill of quantities

Isaac Newton — Fri, 03 Mar 2023 10:34:14 GMT

Thank you very much! I think I've got what was wrong in my calculations. Underneath the doors I have finish floors joining each other together:

Now the doors themselves are raised above the associated level on value equal to the thickness of the floor finish. Therefore they create an opening underneath of them:

But that would be alright, cause the door and this opening together occupy less than 2.5 square metres of area, which is set to be omitted by the rules. The problem is that the a part of the finish floor (namely the XPS sound insulation) has the priority larger than the partiotion wall, and therefore it cuts right through it. I couldn't see that while the door was in place, cause it created this opening anyway, but as I deleted the door, I could see that at once:

Therefore I wonder, if you perhaps know, whether it's possible to make ArchiCAD omit those cuts somehow as well in its calculations, because they all also have the areas of less than 2.5 square metres