In the near shadings you can click on "File > Import > Import CSV ground data" in the menu to import a text file containing 3D coordinates of points.
Here is an example of content for the file you
can import this way :
0 250.01 0.19
5.55 247.2 0
10.05 269.66 0.29
15.63 267.05 0.09
17.56 246.27 0.82
Each line must contain the coordinates for one
point only, in the following order : X Y Z.
The unit is in meters (m), you should make sure that the origin
point is near 0 or the generated ground will appear far from the
scene origin. Anyway, you will be able to move it where you want in
the scene after it has been imported.
You can choose one of the following separators: [TAB] ; , [SPACE]
A ground object will be created as soon as at least three correct and distinct points are found in the file. A triangulation is automatically made in order to physically represent the ground.