In this chapter, you will learn how OPEN BIM projects are shared among architects and structural engineers. You will see how you can save time and money by implementing the OPEN BIM collaboration workflow using AxisVM and ArchiCAD, AutoDesk ADT, Revit, Nemetscheck Allplan, Tekla Structures and other architectural programs.
Let’s summarize the main features of IFC data exchange file format in brief.
→ IFC describes the precise geometry of a 3D building element. For example, in case of a column, its height, width and cross-section.
→ Not only the geometry, but all additional element properties can be stored. For example, for a building element, its material, fire rating, acoustic rating, and function.
→ Ability to filter a large database. You can choose to access or display only the data you are interested in.
→ Ability to use the reference model concept to see and check models of other disciplines.
→ IFC scheme and code are open for all design software. For example, ArchiCAD and AxisVM can collaborate not only with the major but also the local (country leader) applications. Since the IFC scheme is more than 15 years old, it is a highly refined data format.
→ An easy-to-use interface, such as a one-click model export and import. The content of the IFC file can be also read by a simple text editor.
→ Although the official language of the IFC standard is English, its interface can be localized, enabling its use worldwide.
An overview of the main steps of the architectural programs and AxisVM workflow:
1. Let’s start with the architectural model. Architects create an initial model version based on the client’s request and the given site.
2. Architects filter the structural elements by using element classification, layers, layer-combinations, display settings, selection modes and so on to prepare the model for export. Of course, the entire project, without any filtering, can also be exported.
3. The architectural model is exported in IFC file format.
4. Engineers receive the architectural model and open it.
5. Engineers define the structural and so the analysis model and its details based on the referenced architectural model. Engineers can query the initial profiles and materials defined by the architects.
6. They add loads to the structure and run analysis and design calculations according to the required country standard and material definitions.
7. The ready structural model - derived from the analysis model - can be exported back to the architects in IFC file format.
8. The architects can either merge the structural model into their current architectural project or open it as a totally new file. Filtering is also available for the import, and imported elements can be placed on given layers. By default, newly imported elements will be protected from modification, in keeping with the reference model concept. Architects may compare two view sets: one of the architectural model and the other of the imported structural model.
9. Architects can query the profiles and materials used by the engineers and modify their project to match the imported reference model, or they can accept imported elements by using them as real elements.
10. Architects export a new IFC file based on the project’s new status.
11. The new architectural model version can be compared with the previous architectural model version. Changes can be double-checked by the engineer.
12. Based on this comparison, engineers can make changes in the project.
Both engineers and architects can repeat the above-described process of model exchange, comparisons and updates in additional cycles. Finally, the two disciplines make their own or combined documentations.