Convert units to project settings when guessing quantities

src/ifcopenshell-python/ifcopenshell/util/unit.py

@@ -62,3 +62,37 @@ def get_unit_name(text):
     for name in unit_names:
         if name in text.upper().replace('METER', 'METRE'):
             return name
+
+def convert(value, from_prefix, from_unit, to_prefix, to_unit):
+    """Converts between length, area, and volume units
+
+    :param value: The numeric value you want to convert
+    :type value: float
+    :param from_prefix: A prefix from IfcSIPrefix. Can be None.
+    :type from_prefix: string
+    :param from_unit: IfcSIUnitName or IfcConversionBasedUnit.Name
+    :type from_unit: string
+    :param to_prefix: A prefix from IfcSIPrefix. Can be None.
+    :type to_prefix: string
+    :param to_unit: IfcSIUnitName or IfcConversionBasedUnit.Name
+    :type to_unit: string
+    """
+    if from_unit in si_conversions:
+        value *= si_conversions[from_unit]
+    elif from_prefix:
+        value *= get_prefix_multiplier(from_prefix)
+        if 'SQUARE' in from_unit:
+            value *= get_prefix_multiplier(from_prefix)
+        elif 'CUBIC' in from_unit:
+            value *= get_prefix_multiplier(from_prefix)
+            value *= get_prefix_multiplier(from_prefix)
+    if to_unit in si_conversions:
+        return value * (1 / si_conversions[to_unit])
+    elif to_prefix:
+        value *= (1 / get_prefix_multiplier(to_prefix))
+        if 'SQUARE' in from_unit:
+            value *= (1 / get_prefix_multiplier(to_prefix))
+        elif 'CUBIC' in from_unit:
+            value *= (1 / get_prefix_multiplier(to_prefix))
+            value *= (1 / get_prefix_multiplier(to_prefix))
+    return value