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Modeling
About Archicad's design tools, element connections, modeling concepts, etc.

Zone Area Reduction for Low Ceilings Not Applying

Heftor
Booster

Hi,

I'm having trouble getting the automatic area reduction for low ceilings to work and would appreciate some guidance.

This is my ceiling:

Heftor_0-1760453241716.png

 

 

Here is what I have done:

  1. In Project Preferences > Calculation Units & Rules, I went to the Zone Area Calculation section and defined a Reduction for Low Ceilings (e.g., reduce areas with a height below 2m by 50%). 

    Heftor_1-1760453269751.png

     

  2. I then created a zone in a room with a ceiling height lower than my defined limit.

The Problem:
Despite these settings, the "Reduced Area" in the Zone Stamp shows the same value as the "Gross Area." No reduction is being applied.

Heftor_2-1760453382757.png

and there is only the reduction of the walls but nothing else.

Even on the 3D i can see the zones not being right.

 

Heftor_3-1760453494508.png

 

Is there a specific way the ceiling height is measured for this rule to work (e.g., from the active story level, from the floor)?

Are there any common pitfalls that would prevent this rule from triggering?

Do I need to use the "Calculate Zones" command for this to update?

 

Thanks in advance, 

Hector

 

Operating system used: Windows

 

7 REPLIES 7
Barry Kelly
Moderator

I believe you need to trim the zone to the roof (ceiling) for this to be calculated.

 

Barry.

One of the forum moderators.
Versions 6.5 to 27
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Olivier-IDAO
Enthusiast

After you trim the zones, don't forget to update them for re calculation...

 

OL

Interior designer, Former & Bim expert
Archicad 6.5 to 29
MacStudio 2023 Apple M2 Max powered by MacOS Sonoma 14.7.4
Heftor
Booster

Hi @Barry Kelly and @Olivier-IDAO ,

 

OK, I have done what you advised:

 

Screenshot 2025-10-15 115313.png

 

Trimmed to the roof:

 

Heftor_0-1760522178566.png

 

before update:

 

Screenshot 2025-10-15 115351.png

 

After update:

 

Screenshot 2025-10-15 115426.png

 

 but the definitions from the zone doesn´t match:

 

Screenshot 2025-10-15 115437.png

 

 still there is no reduction in the lower part and the crop is almost 1m more deep that the 2m height

 

Heftor_1-1760522381119.png

 

Thanks in advance, 

Regards,

Hector

Hi Heftor,

Wouldn't you have drawn lines as Zone Boundaries where the zone stops?

Or an other idea, you have walls in your ceiling defined by default as Zone Boundaries...

Otherwise I don't see what redefined the zone in this way?

 

Let me know

Olivier

 

Interior designer, Former & Bim expert
Archicad 6.5 to 29
MacStudio 2023 Apple M2 Max powered by MacOS Sonoma 14.7.4

Trimming (or SEO) would not modify the floor plan display of your zone.

What you see is what you maximally get.

Looks like there is something (probably a line with the attribute of zone boundary) in the way, and when you updated the Zone it shrinked to it's current size.

Another reason could be due to Reno: The Zone can only react to what it sees. E.g. if the Zone is set to new, it won't "see" Walls that are set to TBD.

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Laszlo Nagy
Community Admin
Community Admin

@Heftor,

 

Can you select this trimmed Zone (R 5.13) in the Floor Plan and display it in the 3D Viewpoint so that we can see exactly how it looks after trimming?

 

TrimmedZone.png

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Heftor
Booster

Hello all, 

 

I have to isolate the room to find that there is an error, unfortunately I cannot find which is the "line" that´s messing with the room calculation.

So far this is what i did:

Substract the ceiling from room:

Heftor_0-1760609680428.png

Recalculate the room:

Heftor_1-1760609713074.pngHeftor_2-1760609729131.png

and it works

Heftor_3-1760609779752.png

on the real model, I have to find why when i do this steps something is wrong and it was wood structure on the floor plan, I have to hide that layer.

Heftor_4-1760609931697.png

because when i recalculated 

it goes from this:

Heftor_5-1760610005111.png

to:

Heftor_7-1760610490557.png

Because of the wood structure on the floor plan, was cutting the zone, hiding that layer it working fine:

Heftor_8-1760610755582.png

 

Heftor_9-1760610776304.png

 

Thanks again for all the help, we are still fairly new to the archicad workflow 🙏

 

Regards,

Hector

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