NextFEM Designer allows to import and export models in IFC file format, commonly used in projects based on the BIM method, promoting collaboration between designers and reducing the time for designing. The current capabilities offered by Designer will be described in the following.

 

The so-called "BIM", an acronym for Building Information Modeling, is a design method that is becoming established in the building and construction field. Operating with this method means creating virtual models (3D) which, in addition to visual characteristic (solid model with realistic graphic (render) or conceptual representation), contain also information related to geometry, materials and their properties, construction phases, maintenance operations, as well as the features entered by each designer involved (architectural designer, systems designer, structural engineer). The project file can be shared between the various actors in the design process, who interact and integrate the model quickly and congruently with the information already present, thus avoiding interferences and recalculations that often waste a lot of time. The result is an integrated design that proceeds in parallel with everyone's decisions, providing immediate and shared feedback.

In structural design, the BIM operating flow is represented by the continuous iteration between the architectural designer, who generates the geometric model of the project on the basis of the Client's indications, and the structural designer, who calculates the structure and modifies its components to adapt them to the calculations.

 

 

The work of both figures is carried out on a single model, which on one side decreases the probability of errors, on the other it improves data management, the quality of information and promotes the collaborative approach between the different designers, detecting and solving any inconsistencies and errors.

The standard file format for promoting collaboration and information exchange in BIM-based models is the IFC (Industry Foundation Classes). It is an open file format that defines an object-based entity-relationship model. For example, a wall is registered as a "wall" entity but also as belonging to the "windows and doors" category, located on the ground floor, responding to certain thermal characteristics, etc.

 

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The IFC format is used to give the possibility to various software currently on the market to view and modify the same project, even if created with other platforms.

NextFEM Designer supports the automatic import of the models described in IFC format in two distinct ways, using the File/Import ... command.

Importing a structural IFC model (exported from another calculation program or from dedicated software) will import the entire mesh, the load cases and the loads defined inside.

For architectural IFC models (the most common, coming from Revit, All Plan, etc.) the following features are supported:

- IfcBeam (Swept Solid body, Curve2d and Mapped body representations)

- IfcColumn (Swept Solid body, Curve2d and Mapped body representations)

- IfcWall (Swept solid representations)

- IfcSlab (Swept solid representations)

- IfcFooting (Swept solid representations)

- IfcReinforcingBar for longitudinal reinforcements and stirrups

- IfcStructural classes.

 

For slabs, walls and foundations, the program automatically creates a structured mesh, formed by regular quadrilaterals. This feature makes it a valuable and fundamental aid to maintain the accuracy of the structural model.

 

In addition, NextFEM Designer is able to export structural models to IFC files. For example, consider a simple rectangular structure with dimensions 3.00x5.00m, height 3.00m, consisting of reinforced concrete pillars and IPE 180 beams, made by S275 steel, anchored to concrete section C25/30, 18cm thick. For demonstration purposes, the pillars have a rectangular section 40x40cm and a circular one with a 30cm diameter. Once the geometry has been modelled in the Designer and the reinforcements have been assigned, the model is exported in IFC format using the File/Export... command and selecting IFC model (* .ifc) from the drop-down menu.

 

 

To visualize the result, let's try to open the newly created file with an IFC viewer, which allows you to show on screen the data contained in the BIM interchange files. In our case we will use the free software BIM Vision.

The reinforcements are clearly evident in the model, and each element is inserted hierarchically in the constitutive diagram of the BIM (Project - Building - Structural elements), as shown by the IFC Structure panel at the top right.

 

 

 

For example, by selecting the square section pillar you will have access to data such as IFC profile, dimensions and location in the model space. Thanks to this information, the model can be interpreted by other software and exchanged between all the professionals involved in the project.