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WinTess3 and the DXF files

The DXF (Drawing Exchange Format) are for exchanging files in CAD drawings. It is a format created by Autodesk in order to import and export drawings created with AutoCad from / to other programs.

Without being the only interchange format, it is the most known and used, and consequently WinTess3 is it using to interact with other CAD programs.
However, the use of this exchange format can generate certain errors or problems since WinTess3 relates to DXF in different ways:

    1. Menu File | Export DXF
    2. Menu File | Import DXF
    3. Menu File | Create New | Mesh in the window Perimeter, Import DXF button
    4. Menu Auxiliary | Import DXF
    5. Menu Patterns | Draw patterns –> new window –> menu DXF

Menu File | Export DXF

The program exports the structure being analyzed. The program allows to choose which objects we want to export to the DXF file. Each group will be placed in a separate layer, so that it is very easy to enable or disable some layers and see only what we want on the CAD program into which is imported.

Export DXF

Menu File | Import DXF

The menu to import DXF is thought to be able to import the files that it has created WinTess3 across the menu to Export DXF . It is supposed that the user has realized some CAD operation and recovers the file again.

Import DXF

However, this is of little importance since the objects have been saved (nodes, bars, cables, tubes, membrane, etc) from being objects with certain properties to pure straight lines or triangles in space. Therefore, we will lose all the properties by importing them again and we have to assign them again manually.

If we import a file we have created directly in a CAD program, we are in the same situation. The only thing we can import are nodes (NODE), bars (LINE) and triangles (3DFACE).

NOTE:
If there are not known the layers that the file DXF uses, it is best to mark the checkbox “All layers” in order to read the maximum information. Otherwise, it is very possible that we find the unpleasant message that says:

File without data

In fact, WinTess3 is extending little by little the number of entities that it can read from a DXF file, but at the moment (version 3.102) it is not capable of reading arches, certain polylines, circles, etc.

Menu File | New | Mesh (Perimeter window, Import DXF button)

This is a very particular case of reading DXF files. When you click on the import DXF button in Perimeter window , a message appears reminding us that type of entity to be read. At the moment (3.102 version) the program only reads a closed polyline.

Reading of a polyline as perimeter of the mesh

The program allows us to use the Center of coordinates of the DXF file, but in the fairly common case that the user has drawn the polyline without paying much attention about the location of the center of coordinates, it is best to leave to the program that uses the one that suits the best.

Menu Auxiliary | Import DXF

This is another case. It imports a DXF file which does not form part of the tensile structure. Everything you import: points, polylines, lines, triangles, etc, will be part of the set of auxiliary lines (orange colored) that only serves as a reference when it comes to creating nodes, bars, geodesic lines, etc.

Import a DXF as auxiliary lines

In this case it is vital that the Center coordinates of the DXF file matches the Center coordinates of our structure, otherwise it will be chaos and will not serve anything.

The reasons of importing a DXF file as auxiliary vary:

    1. To be able to merge several forms created individually into a single one(menu File | Insert&Merge)
    2. Use the references of a real project
    3. Place the membrane in some coordinates that we have created with a CAD program which does not feel comfortable, etc.
    4. etc.

Menu DXF (Draw patterns window)

Finally we have the last case. It’s for exporting patterns we have created to a DXF file.

Export patterns

There are several reasons for this:

      1. At present most of patterns are cut with a numerical control (CNC) machine. This should provide a digital file with the pattern information organized in layers: cutting, drawing, folding, etc. The DXF format is accepted by almost all of the CNC cutting machines.
      2. Many patterns need to be manipulated for various reasons:
          1. Smooth edges
          2. Draw corners (corner plates)
          3. Make holes
          4. etc.

The easiest way to do this is to use any CAD program and virtually all CAD programs accept DXF files.

Patronaje en DXF

Pattern in DXF

      1. Save the pattern for later tasks without using WinTess3.

Ramon Sastre,
December 2012

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