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12.5.2 Formats for Data Exchange
Formats for Data Exchange
If CAD programs or programs for structural analysis can create files of the types *.stp, *.dxf, *.fem, *.asf, *.dat, *.cfe, or *.ifc, the data can be used as a template for RFEM. Conversely, RFEM is also able to create files in formats suitable for other programs.
To open the dialog box for importing a file, use the menu option
- File → Import.
When the Import as background layer option is selected, RFEM only shows a line model that can be used to set nodes, lines, etc. (see Chapter 11.3.10).
To start the export of an RFEM file, use the menu option
- File → Export.
When using the product interface of the DSTV (German Steel Construction Association), the transfer is not performed with framework files reduced to wireframe models; files contain all model and load data that is necessary for efficient processing. Dlubal Software, like many other software developers, works on the development of this interface. It enables the exchange of data with a variety of programs such as Bentley ProStructure, Tekla Structures, Intergraph Frameworks, Advance Steel, CIS/2 CIMSteel, or cadwork.
The interface generally covers structural and CAD data. RFEM, however, supports only the structural format with specific "entities" that can be found in a description (German only, PDF download at http://www.dlubal.com/de/download/pss_dstv.pdf).
The interface transfers information of nodes, members, and cross-sections including member eccentricities and cross-section rotations. Furthermore, nodal supports, load cases, load combinations, and result combinations are transferred with nodal and member loads as well as imperfections. The results of the calculation can be stored in the exchange file as well.
More settings for the data exchange can be specified in the DSTV (.stp) dialog tab.
RFEM can import and generate tables as *.xls files. Exchanging data with MS Excel is described in Chapter 11.5.6. However, the described option is only available for the active RFEM table. The function described below covers all data of the model at once. Thus, user-defined, external generators for model and load data can be used.
To import an XLS file, open the file in MS Excel first. Then you can use the Microsoft Excel option in the RFEM import dialog box (see Figure 12.44) to open the following dialog box.
Select the Workbook and Worksheets that you want to import. Description, sequence, and structure of worksheets must match the data in RFEM exactly, so that imported data can be correctly written into the RFEM tables. If you are not entirely sure, you can create an XLS file from the current RFEM file for test purposes.
In the Options tab, you can specify if worksheets are imported with or without headers and how formulas are handled in the worksheets.
When exporting a file, it is not necessary to open MS Excel; the program starts automatically.
In the Export of Tables dialog section, select the tables that you want to export. When you activate the Only selected tables option, RFEM enables the corresponding button. Click the button to open another dialog box for specific settings.
In the Formulas and Parameters dialog section of the initial dialog box (Figure 12.48), you can specify whether stored formulas are also transferred between RFEM and Excel during the data exchange.
The RFEM tables can also be exported into the CSV format. The procedure is similar to the export into the MS Excel format (see above).
The DXF format only transfers general information regarding the lines used in the model. RFEM is able to import a line model created in, for example, AutoCAD, as well as to create a DXF file from the current model. A layer is used for each cross-section. Nodal supports, loads, etc. cannot be transferred.
More settings for the data exchange can be defined in the ASCII Format DXF (*.dxf) dialog tab. It is recommended to check the parameters, especially before the import.
It is also recommended to check the length units of the DXF template. Optionally, you can enter an Offset to place the DXF model at a certain distance to the origin. Select the Import 3DFACE as surface option to automatically create 3D surfaces from the DXF template as surfaces in RFEM.
If you want to Import from a specific layer, use the button on the right to select the DXF file. The individual layers are then available for selection in the list.
In most CAD programs the Z-axis is directed upwards, but in RFEM it is normally directed downwards. If you now switch to the second dialog tab in the import dialog box, Detail Settings, and select Down in the list for the Z-axis, weight loads can be entered as positive values in RFEM.
The DXF export also includes values. However, only one value or one group of values is possible. If several values are specified, the first value is always exported and a corresponding message is displayed.
For the DXF export, it is also recommended to check the orientation of the Z-axis.
The Industry Foundation Classes (IFC) are a global standard to exchange data for model-based approaches in the construction industry and are developed by the IAI (International Alliance for Interoperability). The IFC are structured in domains (architecture, design, structural analysis, electrical engineering, etc.). Dlubal Software supports the domain for structural engineering, which allows for the transfer of structural data such as nodes, members, supports, load cases, and loads. The IFC are still under development.
You can find a description of the interface at https://www.buildingsmart.org.
When you export an RFEM model as an IFC model, an analytical model is created in the version IFC 2x Edition 3.
This interface allows you to exchange data with the CAD product MicroStation. You can both import model data and export RFEM files, thus using the possibilities of interoperability. Therefore, a connection to all Bentley applications such as ProSteel is given on the basis of ISM (Integrated Structural Modeling).
The SDNF format (Steel Detailing Neutral File) is used for the data exchange of geometrical data such as nodes, cross-sections, and members with the program Intergraph.
RFEM provides an interface with the program Glaser by Isb Cad. This interface handles the exchange of geometrical and reinforcement data.
If you want to export reinforcement results of the RF-CONCRETE Surfaces add-on module, make sure that surfaces are defined as plane and horizontal, i.e. created in the plane XY.
In the Results - Glaser (.fem) dialog tab, you can specify the reinforcement results that are relevant for the export.
The reinforcements exported to Glaser can be realized graphically in grid points or FE nodes. As they are available as values, it is possible to use them in reinforcement drawings.
The Strakon format *.cfe supports the exchange of geometrical data such as surfaces with the CAD program system STRAKON produced by the software developer Dicad.
In the Results tab of the Export dialog box, you can specify the surfaces whose reinforcements you want to export (see Figure 12.53).
Data can also be exchanged with Nemetschek's Allplan program.
For the export of reinforcement results of the RF-CONCRETE Surfaces add-on module, please note that while surfaces may be defined in any position, they must be plane. During the export, RFEM creates one ASF file per plane surface. For example: When the RFEM model has 12 surfaces, 12 files are created that can be merged into a 3D model in Allplan.
In the Results dialog tab of the Export dialog box, you can specify the surfaces whose reinforcements you want to export.
This interface was developed for the program CADKON by AB STUDIO. It is possible to export plane surfaces with constant thicknesses including openings and material information. Furthermore, you can export the reinforcements of RFEM surfaces into the *.esf format (Engineering Structural Format).
You can use the DXF format for the data import; the ESF format is not supported.
Use the interface with the FE program ANSYS to import files available in the *.ans format. This way, you can also use the data of this multifunctional program for analyses performed with RFEM.
It is also possible to import model data from the structural analysis program Scia by Nemetschek to RFEM, provided that data is available in the *.xml format.
Use this interface to import DOS files from the Dlubal program Plate. Set the directory of the INP folder including input data in the Open dialog box.
To save RFEM files as XML files or templates, use the menu option
- File → Save As.
In the Save As Windows dialog box, use the list to set the desired file type in the Save as type dialog field.
The FT5 format saves the model as a template that can be reimported when you create a new file (see Figure 12.23).
When you save the model as the RFX file type, tabular data is converted into an XML format; the remaining data is saved in binary form. Data is stored in a compressed file that can be opened like a ZIP archive file. With it, it is possible to create files for CAD programs.