Measurement ----------- .. currentmodule:: flow360.component.simulation.measurement .. autofunction:: projected_area .. autofunction:: oriented_bounding_box .. currentmodule:: flow360 ``projected_area`` returns a concrete value immediately, which makes it useful for inspecting a geometry or comparing candidate surface sets. The result is the silhouette union of the selected surfaces: overlapping surfaces are counted once, and duplicates in the input are ignored, so there is no need to deduplicate first. It accepts a single ``Surface``, a single ``SurfaceSelector``, a list mixing the two, or an ``EntityList[Surface]``. For a **reference area**, prefer the recipe: assign :class:`ProjectedArea` to ``ReferenceGeometry.area`` instead of computing a number and storing it. The recipe keeps the surface selection in the uploaded ``simulation.json``, and it is the only path that accounts for half-body meshing automatically -- see :doc:`Reference Geometry `. The result is rasterized rather than integrated exactly, so it carries a small discretization error -- on the order of 0.1% at the default settings. .. admonition:: Half-body domains :class: warning ``projected_area`` measures exactly the surfaces it is given and knows nothing about the meshing settings. With a ``half_body_*`` domain its result therefore describes the geometry as uploaded, not the half that gets meshed. Use :class:`ProjectedArea` rather than scaling the returned value by hand. ``DraftContext.compute_obb()`` remains as a deprecated wrapper around ``measure.oriented_bounding_box()`` and is scheduled for removal in release 26.