SDNF

Overview

Steel Detailing Neutral File (SDNF) was originally defined by Intergraph®, for electronic data exchange between structural engineer's analysis and design systems to steelwork modelling systems. Version 3.0 is the latest format supported by the software industry and this format has been used for many years for transferring even complex plant structures between system like Tekla Structures and plant design systems such as Intergraph’s PDS or Aveva’s PDMS applications.

SDNF format

As a quick overview the SDNF files are split into Packets and records. The main packets are defined as follows:

Packet 00 - Title Packet
Packet 10 - Linear members
Packet 20 - Plate elements
Packet 22 - Hole elements
Packet 30 - Member loads (not supported by Tekla Structures)
Packet 40 - Connection details (not supported by Tekla Structures)
Packet 50 - Grids (not supported by Tekla Structures)
Packet 60 - Curved members

If we look at a SDNF file and just concentrate on Packet 10 (linear member) items, you can see that there are ten lines of records. After the Packet 10 line, units and number of elements, a quick overview of the records would be:

Record 1 - Member ID; Cardinal Point; Status; Class; Type; Mark and Revision
Record 2 – Size; Grade; Rotation etc
Record 3 – Orientation vectors
Record 4 – Offsets information
Record 5 – Offsets information
Record 6 – Release information
Record 7 – Fabrication information
Record 8 – Connection information
Record 9 – Finishes information
Record 10 – Attributes information

Note - for links to specific systems see PDS and PDMS.

How to import SDNF file into Tekla Structures

1. In the Advanced Export Options to set XS_SDNF_CONVERT_PL_PROFILE_TO_PLATE to FALSE.
2. select File - Import – CAD



3. Select the Import model and select the properties button.


4. For the SDNF import only the Conversion, Parameters, SDNF and Report tabs need to be completed. If required the conversion tab can be completed. For more information see conversion file


5. Select the required SDNF file and ensure the Type is set to SDNF.


6. On the SDNF tab select the SDNF format type (2.0 or 3.0). See how to identify various industry files for more information.
Note - It is important that the Consider offsets is set to Yes and the Position Number Type is set to Universal ID in most cases.



7. An import report file can be requested if required.




8. The advanced actions then be set. All the normal values are set and there is no real need to change these settings.



9. Select the 'Apply' and 'OK' buttons and then the 'Import' button on the Import Model form.



10. An import model information dialogue is then selected. In the normal case the 'Accept All' button can be selected.



11. And then you need to confirm that you want to save the imported model for subsequent imports.



12. After importing a model it is recommended to right-click the model view and select the 'Fit Work Area to Entire Model' option, to ensure that the imported model is totally visible. Also if parts are missing then the View depth Up and Down values will need to be increased.

How to create SDNF file in Tekla Structures for PDMS

Firstly it is normally important in the Advanced Export Options to set XS_SDNF_CONVERT_PL_PROFILE_TO_PLATE to FALSE.



For the SDNF file creation only the Conversion, Parameter and SDNF tabs need to be completed..



Note - See Conversion file requirements for further information.



The output file name needs to be completed. It is normal conversion to use a '*.dat' or sometime '*.sdnf' file extension for SDNF files but any extension can be added.




Note - It is important that the Consider offsets is set to Yes and the Position Number Type is set to Universal ID in most cases. 

Once the form is completed then select the Apply and Create and the required file will be created within the current working folder.

Modelling notes
For openings to be transferred the cuts must be created with the 'cut part with polygon' option. In this case all the opening will be transferred as Packet 22 (opening) items, and all other cuts will be ignored.

Curved beams must be created with the curved beam option on the Position Property tab as the curvature for curved members created as polybeams will be ignored.

Also it should be noted that polybeams are unique to Tekla Structures and generally are not transferred. For example if a polybeam is created with a change of direction, when the SDNF file is created only the original straight length will be included within the file and the other elements will be ignored.

In some cases the fitting and connections are not included in the SDNF files. In this case the connection needs to be exploded before the connection parts are included within the export file.