# Export and Meshing¶

To export the geometric model and its assigned structural properties to SOFiSTiK for FE meshing and to use the model in all following downstream structural analysis tasks use the command _sofExportModel, the toolbar quick button or the menu action in the SOFiSTiK menu: SOFiSTiK ‣ Export.

If you trigger this export to SOFiSTiK for the first time, you will be asked to choose your desired SOFiSTiK project type, which can be either a SSD or Teddy project. In this step the associativity between the Rhino project archive (*.3dm file) and the SOFiSTiK project will be established by name matching.

For the actual export a dialog will show up in which general export and meshing parameters can be set. After closing the dialog, the geometry in Rhino with all structural attributes is transferred to SOFiSTiK and meshed.

The structural system can be exported as a whole or partially considering only user selected objects. In case you have defined all your export settings once and want to use them without any further modifications, you can run the model export also in quick and silent mode by right-click on Export in the SOFiSTiK toolbar.

## Meshing dialog¶

The export dialog to set the model export parameter looks as follows:

Within this dialog, the mesh generation can be controlled using a number of parameters:

Parameter Description
Element type
By default, the SOFiSTiK mesher tries to generate a pure quadrilateral mesh on surfaces. Curves will be subdivided into beams.

A generation of triangular FE elements is also possible instead, which is however not recommended as the linear triangular elements provide inferior numeric behaviour compared to the bilinear quadrilateral elements.
Mesh density
This parameter controls globally the size of the FE elements. It basically deﬁnes an upper limit for the size of a beam element or the length of a quad element edge. The mesher is allowed to reduce this size automatically in case of small geometry features or sharp corners according to a set of internal mesh density adaption techniques to guarantee a certain mesh quality.

In addition to this global setting, the size of the elements can also be set in a local scope for each point, line or surface individually.
Reﬁnement around short edges
In the neighborhood of short geometric edges in the model, the mesher reduces the overall mesh size in order to obtain well shaped triangular or quadrilateral elements with low aspect ratio. This parameter controls the ratio between the length of a geometry edge and the local reduction of mesh size.

Increasing this value will yield smaller and more regular quad elements in the vicinity of a local edge. Decreasing this value will result in less elements with larger aspect ratio.
Reﬁnement around structural points
Similar to the previous control the mesh size may also be reduced in the vicinity of the surface corners which results in elements with slightly better quality. This control allows to increase or decrease the effect of this behaviour.
Progression factor
This factor controls the inﬂuence radius within which a local mesh reﬁnement will be faded out to the overall mesh size. A higher value of this factor increases the inﬂuence of a local reﬁnement resulting in better element quality with the drawback of increasing the global element count.

Changing this value is only rarely required. In most cases it can be left at the default setting.

After closing the meshing dialog and starting the actual export by clicking OK, the focus of the screen changes to SOFiSTiK SSD or Teddy / WPS application and meshing of the system might be started automatically. Depending on the size of the structure, meshing might take some time. Upon completion, the resulting ﬁnite element model can be viewed using the SOFiSTiK-Animator. The SOFiSTiK Animator might be started from within Rhino at any time after a model was exported at least once. The resulting FE mesh might also be visualized directly within Rhino using the ‘show FE mesh’ command in the SOFiSTiK toolbar.