Cost estimating with Archicad and TCQ: from the IFC model to the budget

A session in Spanish devoted to cost estimating from an IFC model, presented jointly by SIMBIM and by the ITeC, the Catalan Institute of Construction Technology. Martina D'Andrea works through the preparation and export of the model in Archicad, and a technician from the ITeC continues the workflow in TCQ, the institute's time, cost and quality programme, through to the budget. The level is introductory and everything rests on a single example, the Maison Dom-Ino, with columns, slabs and stairs. The first part insists that Open BIM is a process and not a file format, and that the end use conditions how you model: the same column resolved from slab face to slab face or continuous in height gives different volumes, and the criterion decides the measurement. On that basis, three recommendations are given before exporting: ask what information is needed and filter the model in a view, decide how it should come out by defining a translator, and check the result in a viewer before sending it. The work in Archicad is seen live: a general IFC translator is duplicated to create a dedicated one, the IFC 4 schema is chosen, BREP geometry and the export of the elements taking part in detection are switched on, and in the data conversion the quantities and the properties of building materials, elements and components are ticked. The file is generated from the publisher and opened in Solibri Anywhere to check geometry and metadata, where the difference can be seen between an element classified only in Archicad and a slab coming from the ITeC's eCOB standard. The second part takes place inside TCQ. The possible working schemes are explained, with IFC, with BC3 or with Excel, and the BIM Vision viewer is opened from the programme. In the window for linking BIM objects to work items, items are assigned to each type, copied between identical elements, and the property set is used to indicate which IFC datum feeds each measurement, with formulas where needed. The GUID maintains the link between model and budget, and on the eCOB elements a button is shown that associates the items with the BIM type. The measurements are then imported and the degree of BIM implementation is reviewed, which flags the items that carry a GUID. The session closes with the export of an IFC enriched with budget data, which was not opened live owing to a technical problem, and with a round of questions on platforms, units, translators and databases from other countries.