Oasys GSA Documentation

# Import : AutoCAD

GSA allows you to open/import CAD drawings stored in DWG or DXF formats.

The way in which AutoCAD features are interpreted will depend on the user selections in the CAD Import wizard. The following points should be noted:

  • Layers – Layers can be mapped to element properties in the property tables.
  • Sections – Sections can be set up from layers. The section description must be given in the layer name enclosed in curly braces: { }.
  • Entity colours – Entity colours can be used to map to element group numbers.
  • Lines – These can be used to create 1D (two-noded) elements such as beams bars, ties, struts, etc.
  • Points – These can either be used to create nodal mass or spring support properties or specify pinned restraints.
  • Arc / Circle / Ellipse – These can be interpreted in the same way as lines, but are subdivided either by specifying an angle or a number of segments.
  • Polygon Mesh – These can be interpreted as 2D or 1D elements. Two options are allowed for the polygon mesh; this allows, for example, quad elements to be stiffened by beam elements on the grid lines.
  • 3D Face / Poly Face Mesh – These are interpreted as 2D (3-noded triangle or four-noded quad) elements.

Note: when importing from a Polygon Mesh or 3D Face / Poly Face Mesh and ‘Quad4’ is selected: where two of the four vertices are coincident, a Tri3 element is created; where more than two vertices are coincident an error is reported.

  • Other options – Other post-import options such as selecting units for import, tolerance for collapsing coincident nodes, tolerance for rounding node coordinates etc can also be specified.

CAD files can be imported into your model in 2 ways.

  1. Open a DWG/DXF file – Give the ‘File | Open’ command and, in the Open dialog, set ‘Files of type’ to ‘CAD Files (*.dwg, *.dxf)’. (note that the .dwg or .dxf file must not be
  2. Import an CAD file into an existing model – Give the ‘File | Import | AutoCAD (DWG/DXF files)’ menu command and, in the Import CAD dialog set ‘Files of type’ to DWG or DXF.

Selecting a DWG or DXF file will then open the CAD Import wizard. Follow the wizard instructions to import the drawing into a new GSA model.

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