Example: Wall Volume Calculation

An example of the power of MyBimApi.

This page shows two examples of how to calculate quantities in IFC: analyzing the raw geometry or looking up pre-calculated properties.

The reason we show this example is to highlight the flexibility of MyBimApi. It also shows how you can fine-tune the structure of the response to your needs.

Method 1: Calculation from Geometry

This method uses the ifcopenshell.geom engine to create an explicit shape from the wall's definitions and calculates the exact volume. It is accurate but computationally more expensive.

import ifcopenshell
from ifcopenshell.geom import *
from ifcopenshell.util.shape import *

def run(ifc : ifcopenshell.file):
    def volume(elem):
        # Calculate from geometry
        shp = create_shape(settings(), elem)
        return get_volume(shp.geometry)
    
    return sum(map(volume, ifc.by_type('IfcWall')))
OR

Method 2: Property Lookup

This method relies on the data (Property Sets) attached to the element. It is very fast but depends on the quality of the data in the model (e.g., if the volume was exported correctly).

import ifcopenshell
from ifcopenshell.util.element import *

def run(ifc : ifcopenshell.file):
    def volume(el):
        # Look-up property value
        for di in get_psets(el).values():
            for k, v in di.items():
                if k.lower() == "volume":
                    return v
        return 0
        
    # Sum up volumes found in properties
    return sum(volume(w) for w in ifc.by_type('IfcWall'))

Looking for more examples?

We offer a wide range of example Python scripts in the editor's 'Samples' dropdown menu on your Dashboard.

Use them as a base to fine-tune your own BIM analysis logic.

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