How to Get Room Areas With and Without Plaster Reduction Using the Room-Coverings Add-On

There is no easy, out of the box way to get zone areas both with and without plaster area in Archicad. You could achieve it by modeling the plaster walls as separate simple walls and setting them up to reduce the room area. But to model all plaster manually instead of using composite materials is horrible! With the Room Coverings Add-On you can automate a big chunk of that modeling work. In this post I’ll demonstrate how to use the Add-On to model the separate plaster walls automatically and how to get the room area with and without the subtraction of the plaster area.

Step-By-Step Guide

  1. Setup a room with Construction Method: Inner Edge

    Screenshot of used construction method “Inner Edge” for the zone element.

  2. Setup your plaster wall with Relation to Zones: Reduce Zone Area Only and store it as a favorite

    Screenshot of plaster wall settings. Highlighted setting “Relation to Zones:” with value “Reduce Zone Area Only”.

  3. Use the plaster wall for the wall settings in the Add-On palette, select the zone and execute Add Room Coverings

    Screenshot displaying Room Coverings Add-On palette and created plaster wall covering.

  4. Update the zone with Design -> Update Zones...

  5. Finally setup the zone stamp to display the different area values. The area subtraction due to the new plaster walls happens between Measured Net Area and Reduced Area. You can check the details of the calculation in the AREA CALCULATION section.

    Screenshot of zone stamp settings. Area display options are turned on for “Measured Area” and “Reduced Area”.


And here’s the resulting zone stamp displaying both reduced and non-reduced room areas:

Screenshot of the treated room with the zone stamp displaying two room areas.

Calculation Note

There’s a zone calculation setting in the project preferences which has an effect on this calculation. To get the most accurate calculation, you can decrease the lower limit for Wall Subtraction to 0.00 m² as shown in the following screenshot. You will need to update the zones after changing this setting.

Screenshot of zone calculation settings. Wall subtraction is turned on. It’s value for “If larger than:” is set to 0.00 m² and the subtraction percentage is set to 100%.

Try It Yourself

  1. Download and install the Room Coverings Archicad Add-On. You can add coverings to two rooms with the free demo version!

  2. Follow the step-by-step guide above to create the plaster as walls and show the room areas in a stamp

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