'IFC' is a 3D construction-industry file format for modelling buildings and venues. It is different from the other CAD formats that LEGION Model Builder handles in that its form is designed to mirror the fabric of a real building, meaning that is uses real-life elements like storeys, walls, doors, windows, seats, and so on, rather than layers and polygons. IFC files are constructed hierarchically along the lines of:  model → storey → building elements → sub-elements. Because LEGION Model Builder is a 2D programme, new import procedures are required to translate IFC files into 2D CAD for use in LEGION models.