New FEM Model

Being more a wizard than a dialog, this window contains multiple pages following each other in a typical application. It is opened when choosing the New entry in the Standard toolbar or the File menu, i.e., when starting with a new modelling project.

The wizard is used to decide about the general meshing strategy, to define the geographical extent of the modelling area and the offset of global and local coordinate systems. For general information about the use of coordinate systems in FEFLOW please refer to the coordinate systems page.

Depending on the chosen method, there are up to four pages in the wizard:

Model Target Type

On this page, it has to be decided whether the model to be set up will be two-dimensional or using a layered meshing approach in 3D (2D or layered 3D mesh) , or whether a fully unstructured mesh consisting of tetrahedral elements will be used.

The latter requires the availability of a clean structure of geological units and potential mesh add-ins (surfaces, lines, points) in a suitable file format. No overlaps or gaps in the surface descriptions are tolerated.

Import Type Selection

In case that 2D or layered 3D mesh has been chosen on the Model Target Type page, it has to be decided whether the domain extent is defined manually (Manual domain setup), or by using information from one or a number of maps to be loaded in the next step (Supermesh import from maps). As an alternative, the finite-element mesh itself can be imported from maps (FEM mesh import from maps). In the latter case, an arbitrary number of polygon maps can be selected for import. All maps have to contain either triangles or quad elements, or a combination of both. Overlapping maps are not allowed. At common borders of two maps, the nodes have to match.

In case that the option Fully unstructured 3D mesh has been chosen, maps can be imported as elements for a 3D supermesh (Supermesh import from maps). Alternatively, one suitable map can be imported that contains a 3D mesh (FEM mesh import from maps).

Add maps

This page is shown for all options based on maps. It allows to load maps to the list via the Add map (s) button, and remove maps via the Remove map (s) button. When working towards a 2D or 3D layered mesh, for each map in the list you can choose whether to automatically convert the map features to supermesh elements. Maps with this option unchecked will be imported to the Maps panel and will be used for determining the size of the domain.

When importing maps for creating a 3D unstructured mesh, the two buttons to the right of a map in the list can be used to open the Join Maps and Map Table dialogs, allowing for map joining and SQL selection statements and for checking the map table. It can be chosen whether the maps converted to supermesh elements will also be imported into the Maps panel.

Initial Mesh Extent - Local coordinate system

In case that the manual input for the domain extent has been chosen, here the minimum and maximum x and y coordinates of the local coordinate system are set. Next leads to the definition page for the global coordinate offset, while a click on Finish leads to skipping this step and using identical local and global coordinate systems.

Initial Mesh Extent - Global coordinate offset

As a last step in the manual definition process, the global coordinates of the local coordinate system can be defined, leading to an offset of global and local system. The wizard is completed by clicking on Finish.