DXF Import/Export Utility in S-FRAME Analysis - Tips & Tricks

DXF Import Utility in S-FRAME

If you are experienced with S-FRAME and happen to use AutoCAD or a similar CAD platform, you may have seen there’s an Import/Export Utility in S-FRAME to facilitate the exchange of model data between both software. This is particularly useful if you have a model in a CAD software and require to analyze/design it in a third-party software like S-FRAME.

Even though there are some video tutorials which show how to use the existing DXF Link in S-FRAME, and the steps users must follow, sometimes there are some extra steps depending on the type of model you have in AutoCAD.

This article will take you through some tips and tricks when using this Utility in S-FRAME.

Import DXF:

Some things to consider when importing the DXF Model intro S-FRAME:

  1. It is required to save the S-FRAME file (even if you have an empty file) before running the DXF Utility and importing the DXF File. 
  2. To run the DXF Utility, the user must go to S-FRAME > File > Import > and select ‘DXF…’.
  3. A new Window will open showing three different stages before proceeding with the import:
    1. S-FRAME Objects
    2. DXF Objects
    3. The Preview of your 3D DXF Model

As it can be seen in the image above, the import tool features:

  1. TIP: Layers in your CAD file can be useful not only in the CAD program, but also when importing data into S-FRAME.  It is possible to assign predefined sections, and materials on a layer, by layer basis to your imported CAD geometry, saving you time.
  2. TIP: It is important to note that S-FRAME will not recognize certain elements from the original DXF file (e.g., surfaces or polygons).   For this reason, the command ‘EXPLODE’ could come in very handy, which breaks the shapes into simpler entities, helping the user get around this situation in most cases.  For your information, the DXF link will support the following entities: Lines, 3D Faces, PolyLines, Solids, LwPolylines, Circles, and Arcs.  If you are not using the aforementioned elements in your model, you may not be able to import all objects successfully.
  3. TIP: S-FRAME uses the concept of Centerline modeling, where members and shells are modeled along their centerline, and then section properties, or thicknesses are assigned to those analytical objects, representative of their physical traits. If a model is imported that is not centerline modeled, S-FRAME will assume that each line in the model is at the centerline of a unique member, which may not end up in what the user has intended. In this case, the user may want to consider adding another layer to the AutoCAD file, which includes a member along the centerline of each element (stick model), or perhaps using the Revit Structure Import Link.

Below are some more examples of what we are referring to with Analytical v Physical Member Modelling.

  1. TIP: DXF files, by their nature, are not data rich file formats.  They are great for importing geometry, but will not retain information like section properties, materials, loads, etc. that may have been defined in the CAD software.  This information, however, can be applied through the DXF Import Utility.
  2. TIP: S-FRAME does not support Solid 3D Cad Models.   If you are working with Solid 3D CAD models, you may want to consider using SimSolid, which can directly read this geometry in several common formats.


Export DXF:

Some things to consider when exporting the S-FRAME Model to a DXF File:

  1. S-FRAME assigns the next default naming convention before exporting to the DXF File:

    1. Enter a name for each layer or accept the default.
    2. Choose OK, which opens the Save DXF File As dialog.
    3. Enter a filename and choose OK.
  2. Then, S-Frame converts:
    1. Members into AutoCAD line entities.
    2. Triangular and quadrilateral elements into AutoCAD 3D polygon mesh data.
    3. Section names into line entities.
    4. Joint, member and shell numbers into line entities.
  3. TIP: The name and number layers are frozen in AutoCAD, by default.