...

In this course, we will explore how to deal with this kind of models following some of these approaches.

Level curves

Ensure the default values of  'Automatic collapse' and 'automatic tolerance values' are set in the 'Import and Export' branch of preferences window, and import the file named 'level_curves.dxf' using 

...

After importing the file, we recommend to save the model, so as we can access always to the GiD model with the file already imported.

Creating separated surfaces

It is a model of lines, not of surfaces. Some lines could be used to build surfaces, but it should be a hard task.

...

With this procedure, we can create the three surfaces of the image. The surfaces will have only C0 continuity between them (normals between them are discontinuous), but the shape could be good enough to generate a surface mesh valid for some simulations (see the mesh of the image above).

Creating surface from a family of parallel curves

Another way of create surfaces based on level curves is from a collection of 'near parallel curves'. The surface created will interpolate the curves and will have continuity in normals inside it.

...

As can be seen this may be a manual and tedious procedure to re-build a surfaces model depending on the complexity of it, but in some cases this procedure may be very useful to simplify large models.

Cloud of irregular points

An interesting option is to create a single NURBS surface approximating (not interpolating) a cloud of points. It creates a rectangular shape projecting in a direction (in this case, z direction). To do so, use

...

This allow for example to create a 3D volume box for CFD simulations of the air around the topography.

TIN from points

A simple way to sample points is creating a mesh, and exporting the coordinates of the nodes as a simple text file. Create a new GiD project using

...

Note: It is possible to use collapse of points/nodes/edges to have less triangles

Regular grid from nodes

Create again a new model (Files->New) and import the XYZ file but now as mesh nodes, and without connect them with triangles

...

For instance, subsampling with increment=2 will take into account one of each 2 point data in each direction, like shown in the figure hereafter.

Grid from Internet

GiD 14 incorporates the possibility to obtain a grid from the place of the world we want using:

...