(optionally tweak them manually or with third party tools)
Once you have collected the relavant tiles of your elevation in either DTED2, HGT, or BIL format, you can start working with SBuilders built-in conversion tools. The final map, which builds the basis for your mesh, is a special kind of BMP format containing height values – which is therefore supposed to appear mostly green (for details see Tweaking Your Heightmap).
The easiest way from your source format to the BMP depends upon your source format. For our "Gibraltar" tutorial, we will use BIL data.
Start SBuilder with a new project:
For this tutorial we'll use the project title “Gibraltar”. If you want to change the project title later, you can do that in the project properties (Menu "File --> Properties"). One thing to pay attention to is, that the project titel will not become the filename automatically. You can even have different "Gibraltar" projects by choosing different filenames when saving.
On the “Class Scenery” tab of the initial screen, center your area to the above Lat/Lon (35° 30’ N / 05° 30’ W will do). This will help that your area of interest wouldn't disappear from your screen all of a sudden.
Now we can start using SBuilders built-in conversion tools:
Creating your BMP heightmap from HGT or DTM2 data
Creating your BMP heightmap from BIL data (as used in our tutorial)
Both chapters show you the way to create a BMP heightmap file from your data. If you want, you can edit your scenery by tweaking the BMP heightmap before using it as mesh base file.