Creating a simple terrain
From Mod Wiki
For now a flat terrain is fine to drive and run around on. The example map already has a flat terrain set up. The terrain mesh was added to a map via the Terrain Editor. Here's how...
- Open the Terrain Editor inspector (SHIFTN)
- Right-click (RMB) on the empty field on the left side, and choose New > Tree...
- Select the new Root node. Scroll down the property list on the right until you find the "Model" field.
- Browse to the following terrain model: models/terrain/sdk/etqwmap.lwo.
Some guidelines on making your own terrain model can be found on here.